Lumbar MRI findings in the recumbent and the upright position A prospective observational study on type and frequency of differences by direct comparison

Lumbar MRI findings in the recumbent and the upright position A prospective observational study on type and frequency of differences by direct comparison | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Lumbar MRI findings in the recumbent and the upright position A prospective observational study on type and frequency of differences by direct comparison Klaus Doktor, Werner Vach, Henrik Wulff Christensen, Ulrich Fredberg, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8010874/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 14 You are reading this latest preprint version Abstract Background Recumbent MRI is the most widely used image modality in people with low back pain, however, it has been proposed that upright (standing) MRI has advantages over recumbent MRI because of its ability to assess the effects of being weight-bearing and thus, potentially add clinically helpful information. The aim of this study was to investigate the types and frequencies of differences in lumbar MRI findings, between the recumbent and upright positions, both at the disc level as well as at the participant level. Methods This prospective observational study included a total of 220 individuals, 69 low back pain patients without leg pain, 88 patients with low back pain and leg pain, and 63 no-LBP patients. All participants were first scanned in the recumbent position using 0.5T, 1.5T or 3T MRI units, and then scanned in the upright position using an open 0.5T unit. For a series of 22 common MRI findings of the lumbar spine, differences between the two positions were assessed by direct comparison. Types of differences were classified as “ appeared ”, “ disappeared ”, “ worsened ”, or “ improved ” from the recumbent to the upright position, and separately at the disc levels L3/L4, L4/L5, L5/S1. Results Differences in at least one MRI finding could be observed in about half of all low back pain patients and in one-third of participants without back pain. At the participant level, upgrading of findings, involvement of other discs, or appearance of new findings could be observed rather frequently, whereas downgrading, narrowing or vanishing was rare. Differences were most frequently observed for disc contour (bulge, protrusion, extrusion), lateral recess stenosis, central canal stenosis and annular fissure, and for findings at the L4/L5 disc level. Conclusions Direct comparison of a series of common lumbar MRI findings between the recumbent and the upright position, shows a systematic increase in findings in the upright position. This gives a more detailed and nuanced overall picture of the lumbar spine than previously suggested by studies investigating only single or few findings. The clinical value of this additional information requires further investigation. Upright MRI Weight-bearing MRI Lumbar spine Low back pain Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Background Imaging is often performed to identify potential pathology and degenerative findings in people seeking care for low back pain (LBP)(1; 2). Degeneration in the lumbar spine is also common in people without pain, and the clinical utility of diagnostic imaging is a source of debate(3). It has been suggested that conventional recumbent MRI may underestimate the presence and degree of gravity-dependent degenerative spinal pathology due to the dynamic nature of some degenerative entities such as disc herniation and scoliosis(4–7) . Upright, weight-bearing MRI may avoid this type of bias and suggest a higher diagnostic accuracy. In a recent systematic review of recumbent vs upright MRI of the lumbar spine it could be concluded, that the majority of findings aligned with expectations to be more pronounced or appeared at higher frequencies in the weight-bearing position (8). However, in most of the studies included in the review (6–21), the evaluation of the images was done in two separate steps, i.e., each image was evaluated without explicit reference to the other or explicitly in a blinded fashion. This does not reflect clinical practice for interpreting recumbent vs upright imaging, where the recumbent image is, usually, assessed first and the images from the two positions are then evaluated by direct comparison. In addition, most studies focused on one to five different MRI findings of specific interest, whereas in clinical practice MRI images are evaluated for the presence/grade of multiple/any degenerative differences found. Such a broad view allows to identify a greater overall structural burden on the spine, which could potentially increase the likelihood of pain. Consequently, there is a knowledge gap with respect to the frequency of differences between recumbent and upright position when performed in clinical settings characterized by the evaluation of all relevant findings and a direct comparison of the images from both positions. The current study seeks to fill this gap by addressing the following questions: What types and frequencies of differences are observed at the disc level, when directly comparing upright to recumbent lumbar MRI? Which MRI findings and disc levels are most likely to present a difference in the upright position? How do differences in single findings, at the disc level, impact the overall picture at the participant level? How many findings, with a difference, can be expected in a participant comparing upright to recumbent MRI? Methods This was a prospective observational study. The reporting in the manuscript follows the STROBE guidelines (9). 2.1 Participant populations and study flow Upright MRI may be relevant for different populations. Therefore, we included three populations of clinical relevance: 1) Patients with LBP and leg pain, 2) patients with LBP only, and 3) participants without LBP. All study participants had to fulfill the following criteria: 18–60 years of age; not part of a referral pathway to spinal surgery or another secondary care sector activity; no suspicion of serious pathology, i.e. cancer, infection, or inflammatory disease; able to stand up for at least 20 minutes; able to read and write Danish. Two routes of recruitment were used. Patients who were referred to the Radiology Department, Silkeborg Regional Hospital, for MRI from primary care (general practitioners, or chiropractors) with LBP with or without leg pain for at least 4 weeks were identified and consecutively recruited between February 26th, 2018, and July 6th, 2018. Upon receiving the referrals to conventional MRI, all patients were screened for eligibility according to the inclusion criteria and invited to participate in the study. Participants without LBP were recruited from a local nursing school, among employees at the hospital, or through announcements in workplace environments. They were also invited to participate in the study and were checked for eligibility. After the recruitment of study participants, they were MRI-scanned. A total of 242 individuals were initially enrolled. Six individuals were excluded because of age over 60 years, 6 were excluded because of technical problems with their baseline questionnaires and 10 failed to complete the MRI procedures satisfactorily due to technical or positional issues. The remaining 220 individuals defined our main study population (see Fig. 1 ). 2.2 MRI-procedures Participants from both LBP groups were scanned in the recumbent position in either a Siemens Avanto 1.5T or a Siemens Skyra 3T MRI unit, and all no-LBP participants were scanned in the recumbent position in a Paramed OpenMR 0.5T unit. Participants from all three groups were scanned in the upright position in the Paramed OpenMR 0.5T unit. MRI sequences for all three scanners were: Sagittal T1 and T2 as well as T2 axial at the three lowest lumbar disc levels, see Supplementary Table 1. In the following we refer to disc-levels L3/L4, L4/L5, and L5/S1 as L3, L4, and L5, respectively, for ease of reading. 2.3 Self-reported LBP questionnaire and participant groups All participants were asked to complete a questionnaire, and to give informed consent via REDCap (Research Electronic Data Capture) installed on iPads and used to collect and manage study data(10; 11). The questionnaires covered the following items and instruments: Pain intensity in the back and leg measured on the Numerical Rating Scale (NRS, 0–10), the Fear Avoidance Belief Questionnaire (FABQ, 0–42), the Roland Morris Disability Questionnaire (RMDQ, 0–24), sick leave (days/year), duration of current pain episode (with 8 prespecified categories), height, weight, age, and sex. Participants were assigned to one of three groups based on their self-reports: 1) Localized back pain (no pain below the gluteal folds), or 2) Low back pain and leg pain, radiating below the knees. 3) No-LBP with no functional disability in the past 12 months. 2.4 Selection of MRI findings and expectation of upright MRI difference. Not all MRI findings can be expected to change from a recumbent to an upright MRI. The upright, weight-bearing position generally implies a gravity-induced load on spinal structures. Consequently, we can only expect differences for MRI findings that are sensitive to such a load. The MRI findings selected in this study represented findings with biophysiological reasoning for the expectation of a difference and which have also been investigated previously. Two findings were included despite expecting no difference, as they reflect typical aspects considered in any clinical application of MRI, serving as some type of control finding. They are described in Table 1 , including information about our expectations on the direction of upright difference and reasoning for the expectation. Table 1 The MRI findings selected with expectations and the reasoning behind the expectation for the type of difference (“ no change ”, “ appear ”, “ disappear ”, “ worsen ” and “ improve”) when comparing upright with recumbent position. MRI findings Expectation of difference in upright MRI Reasoning Previous investigations(8) Annular fissure Facet joint morphology: Degeneration , Asymmetry Disappear/Improve Appear/Worsen No change As the weight-bearing load is suppressing joint cysts and fluids. Indicators of degeneration, e.g. subluxation or joint space narrowing, may become more pronounced. Not significantly affected by the vertical load. (7) (7; 12) Disc degeneration Disc contour Types of herniation Appear/Worsen As these parameters reflect the degree and extent of affected disc morphology, e.g. loss of disc height, we generally expect an increased frequency/upgrade. (7; 12) (7; 13; 14) Scoliosis Sinistro convex Detro convex Rotational Appear/Worsen These (semi-)quantitative parameters reflect a systematic change in the relative position of vertebral alignment. (7; 14) Spondylolisthesis Anterior direction Posterior direction Lateral direction Spondylolysis. Appear/Worsen As a measure of the extent of instability exaggerated by weight-bearing. (7; 15) Nerve root compromise Spinal stenosis Central canal Lateral recess Foraminal Appear/Worsen Indicators of neural compromise may become more pronounced as other parameters are affected/worsened, e.g. disc height narrowing, and disc herniations. (7; 13; 16) (7) (5; 14; 16) (14; 16; 17) Interspinous reaction Serious pathology Fracture Malignancy Inflammatory disease Infection Other pathology No change As these parameters are not significantly affected by the vertical load. 2.5 Assessment procedure and MRI findings Information on raters, training, reliability of the MRI assessment in the recumbent position and reliability of differences in MRI findings between the two positions has been published elsewhere (7; 18). The evaluation form was accompanied by an evaluation manual based on existing literature(19–27). The raters first assessed the MRI findings in the recumbent position, see Table 2 . After completing the evaluation of the findings in the recumbent position, the raters retrieved the images from the upright MRI and assessed the same findings relative to the recumbent images. For the evaluation of the differences between the recumbent and the upright MRI, each finding was evaluated at the disk level and, if relevant, separately on the left and right sides. Differences for each MRI finding between recumbent and upright positions were initially assessed, by a direct comparison, as “ no difference ”, “ probable difference ”, or “ definite difference ”, and in the case of the presence of a “ probable” or “ definite” difference , the finding was assessed as “ appeared ”, “ disappeared ”, “ worsened ”, “ improved ” or “ unspecified ”. 2.6 Analytical strategy The distribution of the study population characteristics was described by descriptive statistics. The types of differences observed by the raters at the disc level were described with respect to the distribution of the type and certainty of ratings. The distribution of certainty was compared across disc levels and findings. In all subsequent analyses, no distinction was made between probable and definite differences. To depict the impact of the differences assessed at the disc level for a single participant, we considered three ways of summarizing: 1) Summarizing the differences for single findings across disc levels, 2) Summarizing the differences for single disc levels across findings, and 3) Summarizing all differences in a participant across disc levels and findings. To approach this, we applied a classification system to describe the impact based on the observed differences. The types of impact were “ new ”, “ broader ”, ” worsened ”, “ stayed abnormal ”, “ mixed worsened/improved ”, “ mixed appeared / disappeared ”, “ stayed normal ”, “ improved ”, “ more narrow ” and “ vanished ”. Figure 2 exemplifies this system for the specific case of summarizing differences across disc levels for one finding. For example, “ broader ” refers to a situation where the MRI finding was classified as abnormal in the recumbent image and there was at least one difference classified as “ appear ” for another disc level and no difference classified as “ disappeared ”, whereas “ worsened ” refers to a situation where “ worsened ” was the only type of difference observed at the disc level. A verbal description of all categories of this system as well as an algorithmic description can be found in the Appendix. We applied the same classification system to summarize across all findings for a single disc level by replacing “disc level” with “finding” and for summarizing across all findings and disc level in a single participant by replacing “disc level” with “finding/disc level”. When determining the number of abnormal findings in recumbent position in a participant, the number of findings with a difference in a participant, or the number of participants with an abnormal finding or a difference in a specific finding, we always pooled over the three disc levels. This means a finding was regarded as abnormal if it was abnormal for at least one disc level and a difference was regarded as present if it was observed for at least one disc level. Due to the simultaneous conduct of reliability studies, some participants contributed with three assessments, one for each rater in the reliability study. In all analyses reporting the relative frequency in participants, each assessment contributed with a weight of 1/3. Findings assessed both at the left and right side were handled similarly by giving them a weight of ½. If two weights were present, they were multiplied. All analyses reporting relative frequencies in participants were stratified by participant group. It should be noted that in interpreting differences between the groups, in the no-LBP group we must expect fewer findings in the recumbent position and consequently also fewer differences in the upright position, as differences of the type “ worsened ”, “ improved ” and “ disappeared ” can only happen in case of abnormal findings in the recumbent position. Results 3.1 Study population characteristics including abnormal findings in recumbent position Sixty-nine low back pain patients without leg pain (mean age 42 [ 22 – 56 ], 34 women), 88 patients with low back pain and leg pain (mean age 45 [ 29 – 57 ], 43 women), and 63 individuals without LBP (mean age 36 [ 21 – 53 ], 33 women) were included, see Table 3 . All three groups were nearly balanced with respect to sex. The average age overall was 41.7 years, with the no-LBP group being about five years younger on average. Pain and disability scores were higher in patients with LBP than in the no-LBP group. Table 3 Study population characteristics: N, mean, p10, and p90, or absolute frequency and percentage by participant groups. Group LBP NRS (0–10) Leg pain NRS (0–10) FABQw (0–42) RMDQ (0–24) Sick leave (Days/yr) BMI (kg/m 2 ) Age (Years) Sex Female LBP only (N) Mean(p10-p90) 69 5.0(2–8) 68 1.5(0–5) 57 11.4(0–26) 67 41.4(4.4–82.6) 57 2.1(0–7) 66 26.8(21.9–32.9) 69 42.1(22–56) 34/69 (49.3%) LBP + leg pain (N) Mean(p10-p90) 88 5.6(2–8) 88 5.5(2–8) 78 13.9(1–25) 86 56.1(21.7–86.9) 78 3.7(0–15) 84 27.6(21.8–34.7) 88 45.2(29–57) 43/88 (48.9%) No-LBP (N) Mean(p10-p90) 48 .4(0–1) 49 .8(0–5) 36 3.2(0–15) 45 6.2(0–13.0) 62 .1(0–0) 63 24.1(19.7–28.1) 63 36.4(21–53) 33/63 (52.4%) Total (N) (mean) 205 4.2(0–8) 205 3.0(0–8) 171 10.8(0–24) 198 39.8(0-78.3) 197 2.1(0–7) 213 26.2(21.2–32.9) 220 41.7(22-56.5) 110/220 (50.0%) NRS: Numerical Rating Scale. FABQw: Fear Avoidance Belief Questionnaire (work subscale). RMDQ: Roland Morris Disability Questionnaire. In both groups of patients, about half had five or more abnormal MRI findings in the recumbent position. In participants with no-LBP half of the participants had less than two abnormal findings, see Fig. 3 . Pathologies were identified in four participants, all were classified as "other pathology" and represented incidental findings, e.g. hemangiomas. Supplementary Fig. 1 and Supplementary Table 1, in Appendix, provide a detailed overview of the frequency of findings in the recumbent position. 3.2 Type and frequency of differences observed at the disc level Out of 23,478 classifications of potential differences in MRI findings between the two positions at the disc level, the raters noted a difference in 475 (2.02%) of cases, see Table 4 . “ Worsen ” was the most frequent type of difference reported, followed by “ appear ”, together covering nearly 90% of all differences. “ Disappear ” and “Improve” were both reported in slightly less than 5% of all cases. The raters did not specify the type of difference in 3% of cases. Finding and disk-level specific frequencies can be found in Supplementary Fig. 2. Table 4 Frequency of the types of differences between the recumbent and upright positions at the disc level across all MRI findings. Difference Frequency (%) Appear 187 (39%) Disappear 21 ( 4%) Worsen 236 (50%) Improve 19 ( 4%) Unspecified 12 ( 3%) Total 475 (100%) Of the 475 differences reported, the certainty of the assessments of 270 (57%) were classified as “ probable ” and 205 (43%) as “ definite ”. The latter was chosen most frequently when a difference was classified as “ appear ” (52.9%), followed by “ disappear ” (42.9%), “ worsen ” (38.6%), and finally “ improve ” (21.0%). The raters used “ definite ” most frequently at L3 and least frequently at L5. Among the single findings, “ definite ” was chosen frequently for anteriorlisthesis (87.5%) and scoliosis (68.6%) , and “ probable ” was chosen frequently for retrolisthesis (100%) , facet joint degeneration (70%), nerve root compromise ( 73.1%), and disc degeneration ( 70.0%). Differences in serious pathologies were not observed for any of the groups and therefore are not included in the subsequent analyses. 3.3 Which MRI findings and disc levels are most likely to present a difference? Figure 4 depicts the frequency of the types of differences for each MRI finding. Overall participant groups (cf. totals at the lower right quadrant of the figure), the highest frequencies were observed for disc contour (21%) , lateral recess stenosis (17%), central spinal stenosis (15%), and annular fissure (15%). The lowest frequencies were observed for spondylolisthesis anterior direction (2.6%) , spondylolisthesis posterior direction (1.7%) , and facet joint asymmetry ( 0.15% ) with arcolysis and spondylolisthesis lateral direction never showing a difference between the two positions. Within each participant group, the highest frequency was observed for disc contour, lateral recess stenosis, central spinal stenosis , and annular fissure . Frequencies of differences were generally lower in the no-LBP group. Differences for central stenosis , lateral recess stenosis and annular fissures were observed more frequently for participants with LBP only than with LPB and leg pain. When relating the frequency of a difference between the two positions to the frequency of an abnormal finding in the recumbent position (Fig. 4 ), the MRI-findings with higher prevalences of abnormal findings in the recumbent position were also observed to be different more frequently in the upright position. However, there seem to be two exceptions to this rule: For facet joint degeneration and disc degeneration , differences were observed in less than 5% of the patients despite abnormal findings in more than half of the participants. For s coliosis differences were observed in more than 10% of cases despite a frequency of abnormal findings below 10%. 3.4 What types of impact can be expected at the participant level? “ Staying abnormal ” or “ staying normal ” was generally the most common type of impact at the participant level (70–80%) when summarizing MRI findings across the three disc levels, see Fig. 5 . For those findings with a sufficient frequency of differences, both completely new appearances (“ new ”), a broadening across more disc levels (“ broader” ), and (only) a worsening of findings across already identified disc levels (“ worsened” ) could be observed. For disc contour, “worsened ” was by far the most frequent type of difference (up to 20%), and for scoliosis “ new ” could account for more than 50% of differences, and “ broader ” was never observed. Otherwise, the distribution across these three types of differences was almost balanced. For both disc- and facet joint degeneration change frequencies were never above 5%, and almost entirely seen as “ worsened”. “Vanished”, “more narrow”, and “improved” were usually very rare. Generally, “ vanished ” was only observed for annular fissures , and this was the only finding where nine of the 10 possible types of difference were observed. Supplementary Figs. 3A and 3B in the Appendix provides information about the impact at the participant level when summarizing across all findings or across all findings and levels. According to Supplementary Figs. 3A, disc level L4 presented the most differences between the two positions. At this level nearly 30% of discs showed MRI-findings that either appeared or worsened, compared to approximately 15% at L3 and L5 levels. Seven percent of MRI findings either improved or disappeared at the L4 level compared to 5% at L3 and L5 levels. 3.5 How many findings with a difference between recumbent and upright MRI can be expected in a participant? Overall, differences in one or more MRI findings were seen in about half of the participants in the two patient groups and in about one-third of the participants in the no-LBP group, see Fig. 6 . In approximately one-third of the participants in the two LBP groups, differences were seen for two or more MRI findings compared to a little more than 10% among participants with no-LBP. In all three groups, the number of MRI findings that differed between the two positions was positively associated with the number of “ abnormal” findings in the recumbent position, see Supplementary Fig. 4. When stratified by the number of “ abnormal” findings, no substantial difference between the three participant groups could be observed, see Supplementary Fig. 5. Discussion 4.1 Summary of results This study conducted a direct comparison of common lumbar MRI findings in the recumbent versus upright position, analyzing a series of 22 distinct MRI features across three disc levels. The results led to three new key insights: Prevalence of Positional Differences: In approximately half of all LBP patients, at least one positional difference was observed— and typically there were several differences in a patient. A smaller proportion of differences between the two positions was seen in individuals without LBP. Variability Across MRI Findings: The frequency of positional differences varied substantially between MRI findings. This variation cannot be fully explained by the frequency of abnormalities observed in the recumbent position. Enhanced Diagnostic Insight: The use of both positions offers a more comprehensive and nuanced understanding of the lumbar spine, allowing for a more refined and richer impression in a substantial number of patients. In the following we further elaborate on these key findings and highlight specific observations. Nature and direction of positional differences When positional differences occurred in the upright position, they were typically unfavorable for the patient. In most cases, positional differences meant upgrading of findings, involvement of additional discs levels or appearance of new findings. Downgrading or vanishing of findings were rather rare and mostly limited to annular fissures . In interpreting the fact that there was at least one difference in half of the patients (and typically more than one difference), it should be noted that it is correct to interpret a difference mainly as a move towards a less favorable situation. On the other hand, the occurrence of such differences should not be misinterpreted as a dramatic change from a completely normal MRI to some abnormal MRI at the participant level. Such a change is very rare – which is simply a consequence of the fact that most patients had at least one abnormal finding in the recumbent position. Notably, for disc contour differences, 75% of observed differences represented upgrading of pre-existing findings, indicating that upright MRI may be particularly valuable for assessing the severity at specific levels rather than in detecting new instances at other disc levels. This is consistent with radiographic findings, where disc height reduction is more pronounced in the upright position (32) due to impaired disc resilience under load(33; 34). In contrast, “new” accounted for more than 50% of the differences in scoliosis as already discussed above. Relationship between abnormalities and positional differences Only already abnormal finding s present in the recumbent position can show differences such as “ worsened” , “improved” , or “disappeared” in the upright position. Therefore, the frequency of positional differences is inherently linked to the baseline prevalence of abnormalities as actually observed in this study. However, some findings deviated from this trend. For instance, despite being “abnormal” in more than half of the patients in the recumbent position, disc degeneration and facet degeneration showed rather rarely differences with position, possibly indicating that only advanced cases exhibit positional effects. Reversely, scoliosis “appeared” or “ worsened” in almost 10% of all participants, despite a prevalence of only 7% in the recumbent position. This may reflect the dynamic nature of the spine where curves are likely to be more “natural” in the weight-bearing(35). Also, some participants may have a pain-induced deviation of the lumbar spine rather than true scoliosis and that this pain-induced deviation is increased in the upright position. Interpretation of variability While variation in the frequency of differences across MRI findings has been reported in previous studies (8), cross-study comparisons are often biased due to differences in patient populations. Our study allowed for the first time an unbiased comparison of frequencies across many findings using a consistent cohort and uniquely demonstrates that positional differences were most seen in disc contour changes ( bulge, protrusion, extrusion ), annular fissures , and spinal stenoses (central canal, lateral recess, foraminal) . In contrast, differences in spondylolisthesis , disc degeneration , and facet joint degeneration were rare. The absence of differences for spondylolistheses in the lateral direction could be due to limited coronal sequences available in the upright position (only one coronal scout image) compared to the recumbent position where more coronal images were available. Also, spondylolysis can be challenging to identify on MRI, in general, and on low field MRI in particular. In general, the existence of differences corroborated the choice of MRI-findings, which was driven by the expectation to observe differences in at least some patients – except for serious pathology and facet joint asymmetry . Indeed, a new suspicion of a serious pathology was never observed in the upright position, and a difference in facet joint asymmetry was observed only in one patient. Group comparisons The study included three participant groups. No-LBP individuals showed fewer differences, likely due to fewer baseline abnormalities. Among LBP patients, those without leg pain exhibited more frequent differences in central and lateral recess stenosis and nerve root compromise compared to those with leg pain. This may be due to the latter group already presenting with more severe stenoses in the recumbent position, leaving less room for further change upon weight-bearing. Supplementary Table 2 confirms that LBP patients with leg pain had a higher prevalence of absolute stenosis. 4.2 Comparison with the literature As indicated by a recent systematic review of recumbent vs upright MRI of the lumbar spine, most previous investigations evaluated the two positions independently (8). Thus, direct comparisons with other studies are challenging due to this methodological difference. Hansen et al. is a notable exception, using an approach like ours(16). For five out of seven comparable findings, their results aligned with ours; however, they reported far fewer differences in disc contour and annular fissures. Detailed comparisons are available in Supplementary Table 2. In addition, previous studies have often reported positional MRI differences as rare, particularly in reproducibility studies where raters tend to be more conservative(7; 16). This contrasts with our findings, where half of LBP patients demonstrated at least one difference, and one-third showed two or more. This discrepancy may stem from earlier studies focusing on fewer MRI parameters, whereas our study evaluated a broader set of 22 MRI findings in all participants. 4.3 Clinical and research impact The findings of this study suggest that upright MRI may offer greater clinical value in the evaluation of low back pain than previously recognized. In contrast to earlier studies that focused on only a few imaging features, our comprehensive assessment revealed that positional differences were present in at least one MRI finding in half of all LBP patients. Upright imaging provides a more nuanced view of the lumbar spine revealing additional affected disc levels, making certain abnormalities more visible, or demonstrating increased severity of existing findings. However, it is uncommon for upright MRI to reveal only new findings, as signs of degeneration are generally already detectable in recumbent scans. The clinical value of this additional information is still to be investigated, especially the impact of upright MRI findings on clinical decisions and patient outcomes. Some insights can be obtained by studying whether differences in MRI findings between the two positions correlate, or improve the correlation, with patient-reported symptoms—both localized LBP and radiating leg pain. Further insights can be obtained from studying the impact of adding a recumbent MRI on management decisions and on the satisfaction of patients with respect to understanding their disease status. When it is clarified how clinicians can make the best use of the additional information, the benefit of adding an upright MRI can ultimately be investigated in randomized controlled trials assessing patient outcomes. Interestingly, our results showed that findings classified as “disappeared” were rare and mostly limited to annular fissures – a finding of limited clinical relevance (36). This raises the possibility that upright MRI might eventually replace rather than complement recumbent imaging in selected cases. Our study did not reveal clinically important findings that were missed in the upright position. However, a combined approach may still be preferred, as positional shifts can offer insights into pain mechanisms (e.g., dynamic instability), which would be lost if only one position was assessed. This study also reinforces the well-documented finding that MRI abnormalities may be present in asymptomatic individuals. Upright MRI enhances the visibility of degenerative differences not only in symptomatic patients but also in those without current LBP. Thus, it may aid in early detection of potentially pain-generating changes before symptom onset. Recent systematic reviews suggest that certain MRI features can predict future LBP and disability in asymptomatic patients, further emphasizing the potential prognostic value of upright imaging (37). To capture diagnostic uncertainty, raters were allowed to classify observed differences as either “probable” or “definite.” Over half of the differences were labeled “probable,” highlighting the inherent challenges in evaluating positional differences. This grading system proved useful, especially since “ worsened ” and “ improved ” findings were rated as more difficult to assess than “ appeared ” or “ disappeared ” findings. Unsurprisingly, disc level L5 posed the greatest interpretive challenges, followed by L4 and L3, likely due to its transitional anatomy and technical imaging difficulties. We recommend incorporating similar confidence assessments in future studies. In designing the assessment procedure, we made use of established criteria to evaluate single findings. It can be only speculated to which degree this has facilitated the findings of this study. To improve diagnostic accuracy and consistency, we regarded consensus-based criteria as essential for interpreting upright MRI. We recommend the use of standardized classification systems such as those proposed by Fardon et al. to improve reproducibility and diagnostic confidence(28). 4.4 Limitations of the study This study involved three raters, and a subset of 59 out of 220 participants was assessed by all raters for reliability analysis. Previous findings from this reliability study indicated greater inter-rater consistency for negative assessments compared to positive ones, and differences in rater thresholds for identifying abnormalities were observed(7). Such variability may limit the generalizability of our findings, although similar challenges have been reported in prior research(16). The selection and classification of MRI findings were predefined during the study planning phase. The assessment protocol, requiring 1–2 hours per participant depending on complexity, necessitated a limit on the number of features evaluated. Some potentially informative markers, such as Modic changes, disc bulging in the upright position, and ligamentum flavum contributions, were excluded. While these omissions may be viewed as limitations, they were necessary to ensure feasibility. Additionally, the ordinal classification system used to describe differences (e.g., “ worsened ,” “ appeared ”) may have resulted in a loss of information. Quantitative measures such as angles or distances could provide more precise assessments but would have added considerable time and complexity. Lastly, a potential source of bias was introduced by differences in imaging equipment. Participants outside the clinical referral pathway received recumbent scans on a 0.5T open MRI system, which differed in image quality and sequence parameters from those used for the other groups. As a result, raters may have been able to infer participant group membership, possibly leading to underreporting findings in asymptomatic individuals. We do not regard the use of a low field strength of 0.5T in the recumbent position in non-LBP patients as a problem in itself, as longer scanning times still allow us to obtain a proper image quality. In contrast, in the upright position the use of such low field strength and hence longer scanning times must be expected to have an impact on the image quality due to possible movements of the patient. 4.5 Outlook An upright MRI has to be seen as a promising modality due to its potential diagnostic gain, which still must demonstrate its clinical benefit for patients in well-designed studies. This requires careful considerations about its clinical use. As this study was based on unselected patient cohorts with or without suspected degenerative disease, we investigated the potential value when using upright MRI together with recumbent MRI as a first-choice modality. However, in the future we mainly see a role for upright MRI in LBP patients, where the patient history and clinical findings seem to mismatch the diagnostic imaging findings initially found in conventional recumbent MRI. Image quality may also be an issue to be solved by progress in image processing, as movement of patients can be less controlled in upright MRI. In any case, a potential benefit must be balanced against potential increased costs and stress to patients, as an upright MRI is more time-consuming to perform and may induce discomfort. Hence finally, careful risk-benefit and cost-benefit analyses will be necessary. It can only be hoped that the research interest in upright MRI is increased to clarify its role in clinical practice, which then may be followed by an increased use in clinical practice or its abolishment. Conclusion Direct comparison of a series of common lumbar MRI findings in the recumbent versus the upright positions, shows a systematic increase in findings in the upright position, compared to the recumbent position and may add more information regarding lumbar spine pathology than previously suggested by studies investigating only single or few findings. Further research is needed to investigate the clinical value of upright MRI. Abbreviations LBP Low Back Pain STROBE STrengthening the Reporting of OBservational studies in Epidemiology REDCap Research Electronic Data Capture NRS Numerical Rating Scale FABQ Fear Avoidance Belief Questionnaire RMDQ Roland Morris Disability Questionnaire BMI Body Mass Index Declarations 5.1 Clinical trial number: Not applicable 5.2 Ethics approval and consent to participate Written informed consent was obtained from all participants in this project. Local ethics committee approval was not required due to the methodological nature of the study according to Danish law: § 14, piece 1 in law on scientific ethical handling of health scientific research projects. A letter of exemption from the Scientific Ethics Committee in Region Southern Denmark, Damhaven 12, 7100 Vejle, Denmark, is available from the author on request (case numbers 48336/S-20172000-96). The Danish Data Protection Agency has also approved the project under reference number 2015-414037. All procedures performed in studies involving human subjects were in accordance with the ethical standards of the institutional and/or national research committee and with the Helsinki Declaration of 1964 and its subsequent amendments or comparable ethical standards. 5.3 Consent for publication Not applicable. 5.4 Availability of data and materials The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. 5.5 Competing interests The authors declared that they have no competing interests. 5.6 Funding Funding was provided from the Foundation for Advancement of Chiropractic Research and Postgraduate Education in Denmark and AGFA HealthCare, Belgium. The funders did not have a role in role in the conceptualization, design, data collection, analysis, decision to publish, or preparation of the manuscript. 5.7 Authors' contributions All authors: made substantial contribution to the conception, approved the submitted manuscript and agreed to be personally accountable for the authors own contribution and to ensure that questions related to the accuracy or integrity of any part of the work, even ones in which the author was not personally involved, are appropriately investigated, resolved, and the resolution documented in the literature. Individual contributions: Klaus Doktor – design; acquisition, analysis and interpretation of data; drafted the work or substantively revised it. Werner Vach - design; acquisition; analysis and interpretation of data; drafted the work or substantively revised it. Lau Brix - drafted the work or substantively revised it. Mark Hancock - interpretation of data; drafted the work or substantively revised it. Jan Hartvigsen - design; interpretation of data; drafted the work or substantively revised it. Tue Secher Jensen - design; acquisition, analysis and interpretation of data; drafted the work or substantively revised it. 5.8 Acknowledgements The authors would like to thank radiographers and others participating in the organization of the project: Annette Kryger Jensen, Jonas Knudsen, Birgitte Hornbæk Korsholm, Maria Jendritska Randlev, Brian Højgaard, and Hanne la Cour Ginnerup, Diagnostic Centre, Silkeborg Regional Hospital; Orla Lund Nielsen, Chiropractic Knowledge Hub, and University of Southern Denmark, for support in data handling. Line Thorndal Moll, Department of Public Health, Aarhus University, Denmark, kindly shared her research. References Wang YXJ, Wu AM, Ruiz Santiago F, Nogueira-Barbosa MH. 2018. Informed appropriate imaging for low back pain management: A narrative review. J Orthop Translat 15:21-34 van der Graaf JW, Kroeze RJ, Buckens CFM, Lessmann N, van Hooff ML. 2023. MRI image features with an evident relation to low back pain: a narrative review. European Spine Journal 32:1830-41 Brinjikji W, Luetmer PH, Comstock B, Bresnahan BW, Chen LE, et al. 2015. Systematic literature review of imaging features of spinal degeneration in asymptomatic populations. AJNR. American journal of neuroradiology 36:811-6 Alyas F, Connell D, Saifuddin A. 2008. Upright positional MRI of the lumbar spine. Clin Radiol 63:1035-48 Splendiani A, Perri M, Grattacaso G, Di Tunno V, Marsecano C, et al. 2016. Magnetic resonance imaging (MRI) of the lumbar spine with dedicated G-scan machine in the upright position: a retrospective study and our experience in 10 years with 4305 patients. Radiol Med 121:38-44 Tarantino U, Fanucci E, Iundusi R, Celi M, Altobelli S, et al. 2013. Lumbar spine MRI in upright position for diagnosing acute and chronic low back pain: statistical analysis of morphological changes. Journal of orthopaedics and traumatology : official journal of the Italian Society of Orthopaedics and Traumatology 14:15-22 Doktor K, Hartvigsen J, Hancock M, Christensen HW, Fredberg U, et al. 2022. Reliability of reporting differences in degenerative MRI findings of the lumbar spine from the supine to the upright position. Skeletal Radiol Doktor K, Christensen HW, Jensen TS, Hancock MJ, Vach W, Hartvigsen J. 2025. Upright versus recumbent lumbar spine MRI: Do findings differ systematically, and which correlates better with pain? A systematic review. Spine J von Elm E, Altman DG, Egger M, Pocock SJ, Gotzsche PC, et al. 2014. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: guidelines for reporting observational studies. Int J Surg 12:1495-9 Harris PA, Taylor R, Minor BL, Elliott V, Fernandez M, et al. 2019. The REDCap consortium: Building an international community of software platform partners. Journal of Biomedical Informatics 95:103208 Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. 2009. Research electronic data capture (REDCap)—A metadata-driven methodology and workflow process for providing translational research informatics support. Journal of Biomedical Informatics 42:377-81 Splendiani A, Bruno F, Marsecano C, Arrigoni F, Di Cesare E, et al. 2019. Modic I changes size increase from supine to standing MRI correlates with increase in pain intensity in standing position: uncovering the "biomechanical stress" and "active discopathy" theories in low back pain. Eur Spine J 28:983-92 Nordberg CL, Boesen M, Fournier GL, Bliddal H, Hansen P, Hansen BB. 2021. Positional changes in lumbar disc herniation during standing or lumbar extension: a cross-sectional weight-bearing MRI study. European radiology 31:804-12 Ibrahim H, Diab K. 2021. Unexplained back pain and sciatica: the added value of upright dynamic MRI of the lumbar spine in cases of clinical/radiological mismatch. Egypt J Radiol Nucl Med 52 Muto M, Giurazza F, Guarnieri G, Senese R, Schena E, et al. 2016. Dynamic MR in patients affected by neurogenical claudication: technique and results from a single-center experience. Neuroradiology 58:765-70 Hansen BB, Hansen P, Christensen AF, Trampedach C, Rasti Z, et al. 2018. Reliability of standing weight-bearing (0.25T) MR imaging findings and positional changes in the lumbar spine. Skeletal Radiol 47:25-35 Splendiani A, Ferrari F, Barile A, Masciocchi C, Gallucci M. 2014. Occult neural foraminal stenosis caused by association between disc degeneration and facet joint osteoarthritis: demonstration with dedicated upright MRI system. Radiol Med 119:164-74 Doktor K, Jensen TS, Christensen HW, Fredberg U, Kindt M, et al. 2020. Degenerative findings in lumbar spine MRI: an inter-rater reliability study involving three raters. Chiropr Man Therap 28:8 Pfirrmann CW, Metzdorf A, Zanetti M, Hodler J, Boos N. 2001. Magnetic resonance classification of lumbar intervertebral disc degeneration. Spine (Phila Pa 1976) 26:1873-8 Aprill C, Bogduk N. 1992. High-intensity zone: a diagnostic sign of painful lumbar disc on magnetic resonance imaging. Br J Radiol 65:361-9 Lee S, Lee JW, Yeom JS, Kim KJ, Kim HJ, et al. 2010. A practical MRI grading system for lumbar foraminal stenosis. AJR Am J Roentgenol 194:1095-8 Wildermuth S, Zanetti M, Duewell S, Schmid MR, Romanowski B, et al. 1998. Lumbar spine: quantitative and qualitative assessment of positional (upright flexion and extension) MR imaging and myelography. Radiology 207:391-8 Modic MT, Masaryk TJ, Ross JS, Carter JR. 1988. Imaging of degenerative disk disease. Radiology 168:177-86 Meyerding HW. 1956. Spondylolisthesis; surgical fusion of lumbosacral portion of spinal column and interarticular facets; use of autogenous bone grafts for relief of disabling backache. J Int Coll Surg 26:566-91 Goldstein LA, Waugh TR. 1973. Classification and terminology of scoliosis. Clin Orthop Relat Res :10-22 Cobb JR. 1958. Scoliosis; quo vadis. The Journal of bone and joint surgery. American volume 40-A:507-10 Carrino JA, Lurie JD, Tosteson AN, Tosteson TD, Carragee EJ, et al. 2009. Lumbar spine: reliability of MR imaging findings. Radiology 250:161-70 Fardon DF, Williams AL, Dohring EJ, Murtagh FR, Gabriel Rothman SL, Sze GK. 2014. Lumbar disc nomenclature: version 2.0: Recommendations of the combined task forces of the North American Spine Society, the American Society of Spine Radiology and the American Society of Neuroradiology. Spine J 14:2525-45 Ross JS, Moore KR. 2015. Diagnostic Imaging Spine . Philadelphia, PA 19103-2899: Elsevier Pathria M. 2005. Imaging of spine instability. Seminars in musculoskeletal radiology 9:88-99 Kjaer P, Leboeuf-Yde C, Korsholm L, Sorensen JS, Bendix T. 2005. Magnetic resonance imaging and low back pain in adults: A diagnostic imaging study of 40-year-old men and women. Spine (Philadelphia, Pa. 1976) 30:1173-80 Son S, Lee SG, Kim WK, Ahn Y, Jung JM. 2021. Disc height discrepancy between supine and standing positions as a screening metric for discogenic back pain in patients with disc degeneration. Spine J 21:71-9 Saleem S, Aslam HM, Rehmani MA, Raees A, Alvi AA, Ashraf J. 2013. Lumbar disc degenerative disease: disc degeneration symptoms and magnetic resonance image findings. Asian Spine J 7:322-34 Weiler C, Lopez-Ramos M, Mayer HM, Korge A, Siepe CJ, et al. 2011. Histological analysis of surgical lumbar intervertebral disc tissue provides evidence for an association between disc degeneration and increased body mass index. BMC Res Notes 4:497 Mauch F, Jung C, Huth J, Bauer G. 2010. Changes in the lumbar spine of athletes from supine to the true-standing position in magnetic resonance imaging. Spine (Phila Pa 1976) 35:1002-7 Brinjikji W, Diehn FE, Jarvik JG, Carr CM, Kallmes DF, et al. 2015. MRI Findings of Disc Degeneration are More Prevalent in Adults with Low Back Pain than in Asymptomatic Controls: A Systematic Review and Meta-Analysis. AJNR. American journal of neuroradiology Han CS, Maher CG, Steffens D, Diwan A, Magnussen J, et al. 2023. Some magnetic resonance imaging findings may predict future low back pain and disability: a systematic review. J Physiother 69:79-92 Table 2 Table 2 is available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Appendix.docx Table2.docx Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 29 Dec, 2025 Reviewers agreed at journal 23 Dec, 2025 Reviews received at journal 18 Dec, 2025 Reviewers agreed at journal 18 Dec, 2025 Reviews received at journal 03 Dec, 2025 Reviewers agreed at journal 29 Nov, 2025 Reviews received at journal 20 Nov, 2025 Reviewers agreed at journal 10 Nov, 2025 Reviewers agreed at journal 09 Nov, 2025 Reviewers invited by journal 09 Nov, 2025 Editor assigned by journal 09 Nov, 2025 Editor invited by journal 07 Nov, 2025 Submission checks completed at journal 07 Nov, 2025 First submitted to journal 07 Nov, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8010874","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":545914081,"identity":"b1123ea4-eecf-4d6c-970c-a31252f9e2b8","order_by":0,"name":"Klaus Doktor","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBUlEQVRIiWNgGAWjYBACCQYGA8YGIIOfB0xJgEkGHgYGxhl4tSQwMEj2kKzF4AxEgLAWyQbmjQ9n/rDJNz5zuO3DxzYL2X7pBuYPb9sYZGc2YNcizcBWbLghIc1y29nG5pkz2ySMZ845wCY5t43BeDYOW+QYeMwkHyQcNjA7z9jMzHNGInHDjQQ2Zt42hsR5hLQY90O17L+RwPwZnxZpkJYNQC0GvI1ALRVAWyQSGKRBWnA5TLIZ6JcZaWkGEmcONjPOqJAwnnEjsU1yzjmgp3B4X+J488aHPTY2Bvw96Y8ZPhjUyfbPSD784U2ZjeyMAzisYcYUgsQpDvWjYBSMglEwCogBACRiV2DbxTuqAAAAAElFTkSuQmCC","orcid":"","institution":"Chiropractic Knowledge Hub","correspondingAuthor":true,"prefix":"","firstName":"Klaus","middleName":"","lastName":"Doktor","suffix":""},{"id":545914082,"identity":"100327c2-2ec4-44c0-bc25-813bd02ae6d1","order_by":1,"name":"Werner Vach","email":"","orcid":"","institution":"Basel Academy for Quality and Research in Medicine","correspondingAuthor":false,"prefix":"","firstName":"Werner","middleName":"","lastName":"Vach","suffix":""},{"id":545914083,"identity":"80ec89ce-8f9c-4c59-9f15-5d1fcf12add3","order_by":2,"name":"Henrik Wulff Christensen","email":"","orcid":"","institution":"Chiropractic Knowledge Hub","correspondingAuthor":false,"prefix":"","firstName":"Henrik","middleName":"Wulff","lastName":"Christensen","suffix":""},{"id":545914084,"identity":"d2837727-d796-4082-b0d8-ba6ca476890b","order_by":3,"name":"Ulrich Fredberg","email":"","orcid":"","institution":"Odense University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Ulrich","middleName":"","lastName":"Fredberg","suffix":""},{"id":545914085,"identity":"118c3bf0-0aed-47e7-aa7c-ba47ab42967e","order_by":4,"name":"Morten Kindt","email":"","orcid":"","institution":"University Clinic for Innovative Patient Pathways, Regional Hospital Silkeborg","correspondingAuthor":false,"prefix":"","firstName":"Morten","middleName":"","lastName":"Kindt","suffix":""},{"id":545914086,"identity":"8ff305ad-6c0b-42a4-bb99-2b190d84a150","order_by":5,"name":"Lau Brix","email":"","orcid":"","institution":"University Clinic for Innovative Patient Pathways, Regional Hospital Silkeborg","correspondingAuthor":false,"prefix":"","firstName":"Lau","middleName":"","lastName":"Brix","suffix":""},{"id":545914087,"identity":"643195c9-6d9f-4529-a326-52f9ca2247f3","order_by":6,"name":"Mark Hancock","email":"","orcid":"","institution":"Macquarie University","correspondingAuthor":false,"prefix":"","firstName":"Mark","middleName":"","lastName":"Hancock","suffix":""},{"id":545914088,"identity":"ef0f515a-510b-4727-a182-c6a840d7c6ef","order_by":7,"name":"Jan Hartvigsen","email":"","orcid":"","institution":"University of Southern Denmark","correspondingAuthor":false,"prefix":"","firstName":"Jan","middleName":"","lastName":"Hartvigsen","suffix":""},{"id":545914089,"identity":"02e596b2-834a-49b4-845f-07799f52572a","order_by":8,"name":"Tue Secher Jensen","email":"","orcid":"","institution":"University of Southern Denmark","correspondingAuthor":false,"prefix":"","firstName":"Tue","middleName":"Secher","lastName":"Jensen","suffix":""}],"badges":[],"createdAt":"2025-11-02 12:23:02","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8010874/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8010874/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":96363836,"identity":"a6ef3db9-1259-4343-9a89-42382e848894","added_by":"auto","created_at":"2025-11-20 10:08:08","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2235100,"visible":true,"origin":"","legend":"","description":"","filename":"kdmanuscript071125submissionBMCrevised.docx","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/85c352d79a65400d779ef786.docx"},{"id":96283974,"identity":"1c2b2236-5207-42d3-b7b9-a9b09df2afb2","added_by":"auto","created_at":"2025-11-19 11:51:03","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":11601,"visible":true,"origin":"","legend":"","description":"","filename":"cffd1074f26f4d19b65ad89b0ecb95dc.json","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/b5a3689785e4368fb71ddd06.json"},{"id":96364759,"identity":"9d769188-99ab-453d-b67e-96c643ee28a0","added_by":"auto","created_at":"2025-11-20 10:09:36","extension":"xml","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":335220,"visible":true,"origin":"","legend":"","description":"","filename":"cffd1074f26f4d19b65ad89b0ecb95dc1enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/5534812efda6c8d20c2641f8.xml"},{"id":96363250,"identity":"913e2c83-c1d3-423c-9574-dcd80ad83618","added_by":"auto","created_at":"2025-11-20 10:05:45","extension":"png","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":26735,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/f77e8a3e1bf6d63e48b5125c.png"},{"id":96365581,"identity":"c39e494b-68e5-49fb-8340-9193b6844dea","added_by":"auto","created_at":"2025-11-20 10:10:33","extension":"png","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":72299,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage10.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/1a62b5154408307bd6f305db.png"},{"id":96364789,"identity":"49f68b23-67e9-43c2-80a5-1cdf5cfacc74","added_by":"auto","created_at":"2025-11-20 10:09:39","extension":"png","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":49151,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage11.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/4e51c05a649fb9fa1fd17a6f.png"},{"id":96283981,"identity":"a55aebbc-b37d-4e57-9216-84f78f17df89","added_by":"auto","created_at":"2025-11-19 11:51:03","extension":"png","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":116797,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage12.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/a11f2bbcc151c05ab8225975.png"},{"id":96283992,"identity":"53d96a3a-3589-4f15-aa99-afed40381059","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"png","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":176443,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage13.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/cfb068a82c85aa6bf732af6f.png"},{"id":96283980,"identity":"7d663dd1-f202-406f-9caf-4a17fd89cc11","added_by":"auto","created_at":"2025-11-19 11:51:03","extension":"png","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":103646,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/0cc52bc456ace08100ab817a.png"},{"id":96283989,"identity":"663cc4b0-a353-4609-967a-031c6ba184b7","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"png","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":34297,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/01d1138434cbf43609d395c0.png"},{"id":96364775,"identity":"6777b625-98ac-4f0c-abaf-61cb6895878d","added_by":"auto","created_at":"2025-11-20 10:09:37","extension":"png","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":699641,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/4102887a0f9523050d1b080e.png"},{"id":96364345,"identity":"5abe075e-ad42-46c6-b580-3d7be1595c62","added_by":"auto","created_at":"2025-11-20 10:09:13","extension":"jpeg","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1344191,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/8bf75cfbb088398bb0ed90e8.jpeg"},{"id":96283988,"identity":"4d32258f-6330-4acf-ab64-e73bcef2ad76","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"png","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":30250,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/504c55acec7f9fdd7cb1b584.png"},{"id":96364221,"identity":"9d40fe8d-a9be-460b-b714-708ac6fac6ed","added_by":"auto","created_at":"2025-11-20 10:09:03","extension":"emf","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":76816,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage7.emf","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/557638f34e6db11680f64b44.emf"},{"id":96364630,"identity":"69571534-df83-4577-9226-187f833d0a12","added_by":"auto","created_at":"2025-11-20 10:09:29","extension":"png","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":345845,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/5ee400269000cf7919de176e.png"},{"id":96364193,"identity":"54f94fdd-1bee-454f-99ce-ce7d4b8b2349","added_by":"auto","created_at":"2025-11-20 10:09:01","extension":"png","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":167210,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/33a507c5855fa0d50ae24739.png"},{"id":96363423,"identity":"4b58e6c7-9708-4ab4-b5fc-b2da54f5f8ff","added_by":"auto","created_at":"2025-11-20 10:06:45","extension":"png","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":10858,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/2ff3c3dfce3f70551c47a61b.png"},{"id":96364231,"identity":"018d2658-0619-4f0c-b071-e6d20fcb870e","added_by":"auto","created_at":"2025-11-20 10:09:05","extension":"png","order_by":17,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":23159,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage10.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/32e7ba753353f563b3b477ac.png"},{"id":96363883,"identity":"1f3bb37a-ff1e-4805-b0f2-66325adae841","added_by":"auto","created_at":"2025-11-20 10:08:22","extension":"png","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":17580,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage11.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/83326ba65a64c6a5eb4a8824.png"},{"id":96283984,"identity":"ca6804c8-7db6-49cc-bdcf-07363fc22aab","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"png","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":64671,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage12.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/42d2fa11e6b1080e4682ac43.png"},{"id":96283994,"identity":"0a177c19-853d-43d6-887e-98ae9037f3f9","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"png","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":52683,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage13.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/3efdb70910848333a38de6de.png"},{"id":96363367,"identity":"e7258e3e-8980-431a-abbe-b6f220a9f2c7","added_by":"auto","created_at":"2025-11-20 10:06:25","extension":"png","order_by":21,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":40773,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/979b53c744408b36cfec38e9.png"},{"id":96284001,"identity":"daa5ec71-eab3-4cd4-a08e-ad44cb68773d","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"png","order_by":22,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":13893,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/012af8db9104da2cba479e8a.png"},{"id":96284007,"identity":"a7b56016-2812-4bcb-bf55-25111b6fd963","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"png","order_by":23,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":157423,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/76817ab54dab98f11db79d4d.png"},{"id":96283999,"identity":"763331e6-2042-40ed-bb33-49d996841dc8","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"png","order_by":24,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":225483,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/b9a95b0b9ca4dcaff8e38048.png"},{"id":96284004,"identity":"53ba244c-8f9f-4202-a7c1-ff3e888a5cbe","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"png","order_by":25,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":15345,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/44bf610e01b0589efad79d83.png"},{"id":96284003,"identity":"8190fa2d-b151-4185-be92-bdbdeb5d6330","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"png","order_by":26,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":111069,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/7cc83c45edbe7e82b4a5b63b.png"},{"id":96284006,"identity":"e9969c50-562f-44e9-9cca-9b98144a4b3f","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"png","order_by":27,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":123378,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/f971c5f5f9d4add1fd019837.png"},{"id":96364340,"identity":"c6fea22f-e9f5-4b4c-b074-720586a23d96","added_by":"auto","created_at":"2025-11-20 10:09:13","extension":"png","order_by":28,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":52598,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/60909b062cd2ef223337e3db.png"},{"id":96284005,"identity":"ce1cc3a0-d9db-4c7a-98a6-7ce1cd737830","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"xml","order_by":29,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":329382,"visible":true,"origin":"","legend":"","description":"","filename":"cffd1074f26f4d19b65ad89b0ecb95dc1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/e2b6234877af16b62718ec85.xml"},{"id":96284008,"identity":"b482d1e6-cff4-4311-863f-af7d670e68c6","added_by":"auto","created_at":"2025-11-19 11:51:04","extension":"html","order_by":30,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":362025,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/5470528ace81ece54ee0b8ce.html"},{"id":96364678,"identity":"4cf162be-1774-4ee0-825a-55cf7b4fa400","added_by":"auto","created_at":"2025-11-20 10:09:32","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":26735,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart of selection of the study population\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/dd69ebee9d3c6ad1a79d1442.png"},{"id":96283972,"identity":"d5a122ff-7e33-4b22-8bd8-69c0323bad71","added_by":"auto","created_at":"2025-11-19 11:51:03","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":122823,"visible":true,"origin":"","legend":"\u003cp\u003eClassification system for the impact at the participant level shown as a flow chart. In this figure location(s) refer to disc level(s) L3, L4, and L5.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/56956a31070c72ecd9ba747b.png"},{"id":96364288,"identity":"26cdcf39-36ea-4e6c-9250-0804eb3d5052","added_by":"auto","created_at":"2025-11-20 10:09:09","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":34297,"visible":true,"origin":"","legend":"\u003cp\u003eDistribution of the number of abnormal MRI findings in the recumbent position, stratified by participant group.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/b2759eb8977ccb70d0c3811e.png"},{"id":96363518,"identity":"413a8d89-f092-488f-9001-ba1d3bbe3471","added_by":"auto","created_at":"2025-11-20 10:07:12","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":699641,"visible":true,"origin":"","legend":"\u003cp\u003eThe frequency of abnormal findings in the recumbent position and the frequency of differences between the recumbent and the upright position for each MRI-finding. The relationship between these two numbers is depicted in scatterplots stratified by participant group. In the no-LBP group, the findings for spondylolistheses and spondylolysis are not labeled. They all had a frequency of 0 for both abnormal findings and differences\u003cem\u003e.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/6ce7eb08541222213e642a23.png"},{"id":96365568,"identity":"1e2c8678-64fa-4f26-b07b-059da43ea6e6","added_by":"auto","created_at":"2025-11-20 10:10:32","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":875319,"visible":true,"origin":"","legend":"\u003cp\u003eThe frequency of the different types of impact at the participant level when summarizing across the three disc levels L3-L5 for each finding stratified by participant group. For scoliosis, the results refer to summarizing across the three findings sinistro convex, dextro convex, and rotational scoliosis instead of across disc levels.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/87b845ead0c34aded2e244f7.png"},{"id":96283977,"identity":"7e616130-29b3-490c-8276-e23816e3e6c5","added_by":"auto","created_at":"2025-11-19 11:51:03","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":30250,"visible":true,"origin":"","legend":"\u003cp\u003eThe distribution of the number differences in MRI findings from recumbent to upright position stratified by participant group.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/0fb3b919b1ff6588daeaba34.png"},{"id":96708057,"identity":"739ac174-681c-4d35-9ee7-26fd97a64148","added_by":"auto","created_at":"2025-11-25 09:54:31","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2658216,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/21452605-6988-49da-a24d-b4e58e768003.pdf"},{"id":96283970,"identity":"f2d9dacf-ced2-4035-aba5-f01364f6e554","added_by":"auto","created_at":"2025-11-19 11:51:03","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1010718,"visible":true,"origin":"","legend":"","description":"","filename":"Appendix.docx","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/265c53df43d8cfdfec091abb.docx"},{"id":96283971,"identity":"f26bfe18-c668-469e-8a91-f1d34082c6b1","added_by":"auto","created_at":"2025-11-19 11:51:03","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":31917,"visible":true,"origin":"","legend":"","description":"","filename":"Table2.docx","url":"https://assets-eu.researchsquare.com/files/rs-8010874/v1/e6703b75e51b328e66e014ca.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Lumbar MRI findings in the recumbent and the upright position A prospective observational study on type and frequency of differences by direct comparison","fulltext":[{"header":"Background","content":"\u003cp\u003eImaging is often performed to identify potential pathology and degenerative findings in people seeking care for low back pain (LBP)(1; 2). Degeneration in the lumbar spine is also common in people without pain, and the clinical utility of diagnostic imaging is a source of debate(3).\u003c/p\u003e\u003cp\u003eIt has been suggested that conventional recumbent MRI may underestimate the presence and degree of gravity-dependent degenerative spinal pathology due to the dynamic nature of some degenerative entities such as \u003cem\u003edisc herniation\u003c/em\u003e and \u003cem\u003escoliosis(4–7)\u003c/em\u003e. Upright, weight-bearing MRI may avoid this type of bias and suggest a higher diagnostic accuracy.\u003c/p\u003e\u003cp\u003eIn a recent systematic review of recumbent vs upright MRI of the lumbar spine it could be concluded, that the majority of findings aligned with expectations to be more pronounced or appeared at higher frequencies in the weight-bearing position (8). However, in most of the studies included in the review (6–21), the evaluation of the images was done in two separate steps, i.e., each image was evaluated without explicit reference to the other or explicitly in a blinded fashion. This does not reflect clinical practice for interpreting recumbent vs upright imaging, where the recumbent image is, usually, assessed first and the images from the two positions are then evaluated by direct comparison. In addition, most studies focused on one to five different MRI findings of specific interest, whereas in clinical practice MRI images are evaluated for the presence/grade of multiple/any degenerative differences found. Such a broad view allows to identify a greater overall structural burden on the spine, which could potentially increase the likelihood of pain.\u003c/p\u003e\u003cp\u003eConsequently, there is a knowledge gap with respect to the frequency of differences between recumbent and upright position when performed in clinical settings characterized by the evaluation of all relevant findings and a direct comparison of the images from both positions. The current study seeks to fill this gap by addressing the following questions:\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eWhat types and frequencies of differences are observed at the disc level, when directly comparing upright to recumbent lumbar MRI?\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eWhich MRI findings and disc levels are most likely to present a difference in the upright position?\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eHow do differences in single findings, at the disc level, impact the overall picture at the participant level?\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eHow many findings, with a difference, can be expected in a participant comparing upright to recumbent MRI?\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eThis was a prospective observational study. The reporting in the manuscript follows the STROBE guidelines (9).\u003c/p\u003e\n\u003ch2\u003e2.1 Participant populations and study flow\u003c/h2\u003e\n\u003cp\u003eUpright MRI may be relevant for different populations. Therefore, we included three populations of clinical relevance: 1) Patients with LBP and leg pain, 2) patients with LBP only, and 3) participants without LBP. All study participants had to fulfill the following criteria: 18\u0026ndash;60 years of age; not part of a referral pathway to spinal surgery or another secondary care sector activity; no suspicion of serious pathology, i.e. cancer, infection, or inflammatory disease; able to stand up for at least 20 minutes; able to read and write Danish.\u003c/p\u003e\n\u003cp\u003eTwo routes of recruitment were used. Patients who were referred to the Radiology Department, Silkeborg Regional Hospital, for MRI from primary care (general practitioners, or chiropractors) with LBP with or without leg pain for at least 4 weeks were identified and consecutively recruited between February 26th, 2018, and July 6th, 2018. Upon receiving the referrals to conventional MRI, all patients were screened for eligibility according to the inclusion criteria and invited to participate in the study. Participants without LBP were recruited from a local nursing school, among employees at the hospital, or through announcements in workplace environments. They were also invited to participate in the study and were checked for eligibility.\u003c/p\u003e\n\u003cp\u003eAfter the recruitment of study participants, they were MRI-scanned.\u003c/p\u003e\n\u003cp\u003eA total of 242 individuals were initially enrolled. Six individuals were excluded because of age over 60 years, 6 were excluded because of technical problems with their baseline questionnaires and 10 failed to complete the MRI procedures satisfactorily due to technical or positional issues. The remaining 220 individuals defined our main study population (see Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n\u003ch2\u003e2.2 MRI-procedures\u003c/h2\u003e\n\u003cp\u003eParticipants from both LBP groups were scanned in the recumbent position in either a Siemens Avanto 1.5T or a Siemens Skyra 3T MRI unit, and all no-LBP participants were scanned in the recumbent position in a Paramed OpenMR 0.5T unit. Participants from all three groups were scanned in the upright position in the Paramed OpenMR 0.5T unit. MRI sequences for all three scanners were: Sagittal T1 and T2 as well as T2 axial at the three lowest lumbar disc levels, see Supplementary Table\u0026nbsp;1. In the following we refer to disc-levels L3/L4, L4/L5, and L5/S1 as L3, L4, and L5, respectively, for ease of reading.\u003c/p\u003e\n\u003ch2\u003e2.3 Self-reported LBP questionnaire and participant groups\u003c/h2\u003e\n\u003cp\u003eAll participants were asked to complete a questionnaire, and to give informed consent via REDCap (Research Electronic Data Capture) installed on iPads and used to collect and manage study data(10; 11). The questionnaires covered the following items and instruments: Pain intensity in the back and leg measured on the Numerical Rating Scale (NRS, 0\u0026ndash;10), the Fear Avoidance Belief Questionnaire (FABQ, 0\u0026ndash;42), the Roland Morris Disability Questionnaire (RMDQ, 0\u0026ndash;24), sick leave (days/year), duration of current pain episode (with 8 prespecified categories), height, weight, age, and sex.\u003c/p\u003e\n\u003cp\u003eParticipants were assigned to one of three groups based on their self-reports: 1) Localized back pain (no pain below the gluteal folds), or 2) Low back pain and leg pain, radiating below the knees. 3) No-LBP with no functional disability in the past 12 months.\u003c/p\u003e\n\u003ch2\u003e2.4 Selection of MRI findings and expectation of upright MRI difference.\u003c/h2\u003e\n\u003cp\u003eNot all MRI findings can be expected to change from a recumbent to an upright MRI. The upright, weight-bearing position generally implies a gravity-induced load on spinal structures. Consequently, we can only expect differences for MRI findings that are sensitive to such a load. The MRI findings selected in this study represented findings with biophysiological reasoning for the expectation of a difference and which have also been investigated previously. Two findings were included despite expecting no difference, as they reflect typical aspects considered in any clinical application of MRI, serving as some type of control finding.\u003c/p\u003e\n\u003cp\u003eThey are described in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e, including information about our expectations on the direction of upright difference and reasoning for the expectation.\u003c/p\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eThe MRI findings selected with expectations and the reasoning behind the expectation for the type of difference (\u0026ldquo;\u003cem\u003eno change\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003eappear\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003edisappear\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003eworsen\u003c/em\u003e\u0026rdquo; and \u0026ldquo;\u003cem\u003eimprove\u0026rdquo;)\u003c/em\u003e when comparing upright with recumbent position.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMRI findings\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eExpectation of difference in upright MRI\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eReasoning\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePrevious investigations(8)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAnnular fissure\u003c/p\u003e\n \u003cp\u003eFacet joint morphology:\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eDegeneration\u003c/em\u003e,\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eAsymmetry\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDisappear/Improve\u003c/p\u003e\n \u003cp\u003eAppear/Worsen\u003c/p\u003e\n \u003cp\u003eNo change\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAs the weight-bearing load is suppressing joint cysts and fluids.\u003c/p\u003e\n \u003cp\u003eIndicators of degeneration, e.g. subluxation or joint space narrowing, may become more pronounced.\u003c/p\u003e\n \u003cp\u003eNot significantly affected by the vertical load.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(7)\u003c/p\u003e\n \u003cp\u003e(7; 12)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDisc degeneration\u003c/p\u003e\n \u003cp\u003eDisc contour\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eTypes of herniation\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAppear/Worsen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAs these parameters reflect the degree and extent of affected disc morphology, e.g. loss of disc height, we generally expect an increased frequency/upgrade.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(7; 12)\u003c/p\u003e\n \u003cp\u003e(7; 13; 14)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eScoliosis\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eSinistro convex\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eDetro convex\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eRotational\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAppear/Worsen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThese (semi-)quantitative parameters reflect a systematic change in the relative position of vertebral alignment.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(7; 14)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSpondylolisthesis\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eAnterior direction\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ePosterior direction\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eLateral direction\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eSpondylolysis.\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAppear/Worsen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAs a measure of the extent of instability exaggerated by weight-bearing.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(7; 15)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNerve root compromise\u003c/p\u003e\n \u003cp\u003eSpinal stenosis\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eCentral canal\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eLateral recess\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eForaminal\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAppear/Worsen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIndicators of neural compromise may become more pronounced as other parameters are affected/worsened, e.g. disc height narrowing, and disc herniations.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(7; 13; 16)\u003c/p\u003e\n \u003cp\u003e(7)\u003c/p\u003e\n \u003cp\u003e(5; 14; 16)\u003c/p\u003e\n \u003cp\u003e(14; 16; 17)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eInterspinous reaction\u003c/p\u003e\n \u003cp\u003eSerious pathology\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eFracture\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eMalignancy\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eInflammatory disease\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eInfection\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eOther pathology\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo change\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAs these parameters are not significantly affected by the vertical load.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003ch2\u003e2.5 Assessment procedure and MRI findings\u003c/h2\u003e\n\u003cp\u003eInformation on raters, training, reliability of the MRI assessment in the recumbent position and reliability of differences in MRI findings between the two positions has been published elsewhere (7; 18). The evaluation form was accompanied by an evaluation manual based on existing literature(19\u0026ndash;27).\u003c/p\u003e\n\u003cp\u003eThe raters first assessed the MRI findings in the recumbent position, see Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eAfter completing the evaluation of the findings in the recumbent position, the raters retrieved the images from the upright MRI and assessed the same findings relative to the recumbent images. For the evaluation of the differences between the recumbent and the upright MRI, each finding was evaluated at the disk level and, if relevant, separately on the left and right sides. Differences for each MRI finding between recumbent and upright positions were initially assessed, by a direct comparison, as \u0026ldquo;\u003cem\u003eno difference\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003eprobable difference\u003c/em\u003e\u0026rdquo;, or \u0026ldquo;\u003cem\u003edefinite difference\u003c/em\u003e\u0026rdquo;, and in the case of the presence of a \u0026ldquo;\u003cem\u003eprobable\u0026rdquo;\u003c/em\u003e or \u0026ldquo;\u003cem\u003edefinite\u0026rdquo; difference\u003c/em\u003e, the finding was assessed as \u0026ldquo;\u003cem\u003eappeared\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003edisappeared\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003eworsened\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003eimproved\u003c/em\u003e\u0026rdquo; or \u0026ldquo;\u003cem\u003eunspecified\u003c/em\u003e\u0026rdquo;.\u003c/p\u003e\n\u003ch2\u003e2.6 Analytical strategy\u003c/h2\u003e\n\u003cp\u003eThe distribution of the study population characteristics was described by descriptive statistics.\u003c/p\u003e\n\u003cp\u003eThe types of differences observed by the raters at the disc level were described with respect to the distribution of the type and certainty of ratings. The distribution of certainty was compared across disc levels and findings. In all subsequent analyses, no distinction was made between probable and definite differences.\u003c/p\u003e\n\u003cp\u003eTo depict the impact of the differences assessed at the disc level for a single participant, we considered three ways of summarizing: 1) Summarizing the differences for single findings across disc levels, 2) Summarizing the differences for single disc levels across findings, and 3) Summarizing all differences in a participant across disc levels and findings. To approach this, we applied a classification system to describe the impact based on the observed differences. The types of impact were \u0026ldquo;\u003cem\u003enew\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003ebroader\u003c/em\u003e\u0026rdquo;, \u0026rdquo;\u003cem\u003eworsened\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003estayed abnormal\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003emixed worsened/improved\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003emixed appeared\u003c/em\u003e/\u003cem\u003edisappeared\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003estayed normal\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003eimproved\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003emore narrow\u003c/em\u003e\u0026rdquo; and \u0026ldquo;\u003cem\u003evanished\u003c/em\u003e\u0026rdquo;. Figure\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e exemplifies this system for the specific case of summarizing differences across disc levels for one finding. For example, \u0026ldquo;\u003cem\u003ebroader\u003c/em\u003e\u0026rdquo; refers to a situation where the MRI finding was classified as abnormal in the recumbent image and there was at least one difference classified as \u0026ldquo;\u003cem\u003eappear\u003c/em\u003e\u0026rdquo; for another disc level and no difference classified as \u0026ldquo;\u003cem\u003edisappeared\u003c/em\u003e\u0026rdquo;, whereas \u0026ldquo;\u003cem\u003eworsened\u003c/em\u003e\u0026rdquo; refers to a situation where \u0026ldquo;\u003cem\u003eworsened\u003c/em\u003e\u0026rdquo; was the only type of difference observed at the disc level. A verbal description of all categories of this system as well as an algorithmic description can be found in the Appendix.\u003c/p\u003e\n\u003cp\u003eWe applied the same classification system to summarize across all findings for a single disc level by replacing \u0026ldquo;disc level\u0026rdquo; with \u0026ldquo;finding\u0026rdquo; and for summarizing across all findings and disc level in a single participant by replacing \u0026ldquo;disc level\u0026rdquo; with \u0026ldquo;finding/disc level\u0026rdquo;.\u003c/p\u003e\n\u003cp\u003eWhen determining the number of abnormal findings in recumbent position in a participant, the number of findings with a difference in a participant, or the number of participants with an abnormal finding or a difference in a specific finding, we always pooled over the three disc levels. This means a finding was regarded as abnormal if it was abnormal for at least one disc level and a difference was regarded as present if it was observed for at least one disc level.\u003c/p\u003e\n\u003cp\u003eDue to the simultaneous conduct of reliability studies, some participants contributed with three assessments, one for each rater in the reliability study. In all analyses reporting the relative frequency in participants, each assessment contributed with a weight of 1/3. Findings assessed both at the left and right side were handled similarly by giving them a weight of \u0026frac12;. If two weights were present, they were multiplied.\u003c/p\u003e\n\u003cp\u003eAll analyses reporting relative frequencies in participants were stratified by participant group. It should be noted that in interpreting differences between the groups, in the no-LBP group we must expect fewer findings in the recumbent position and consequently also fewer differences in the upright position, as differences of the type \u0026ldquo;\u003cem\u003eworsened\u003c/em\u003e\u0026rdquo;, \u0026ldquo;\u003cem\u003eimproved\u003c/em\u003e\u0026rdquo; and \u0026ldquo;\u003cem\u003edisappeared\u003c/em\u003e\u0026rdquo; can only happen in case of abnormal findings in the recumbent position.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Study population characteristics including abnormal findings in recumbent position\u003c/h2\u003e\u003cp\u003eSixty-nine low back pain patients without leg pain (mean age 42 [\u003cspan additionalcitationids=\"CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36 CR37 CR38 CR39 CR40 CR41 CR42 CR43 CR44 CR45 CR46 CR47 CR48 CR49 CR50 CR51 CR52 CR53 CR54 CR55\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e], 34 women), 88 patients with low back pain and leg pain (mean age 45 [\u003cspan additionalcitationids=\"CR30 CR31 CR32 CR33 CR34 CR35 CR36 CR37 CR38 CR39 CR40 CR41 CR42 CR43 CR44 CR45 CR46 CR47 CR48 CR49 CR50 CR51 CR52 CR53 CR54 CR55 CR56\" citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e], 43 women), and 63 individuals without LBP (mean age 36 [\u003cspan additionalcitationids=\"CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36 CR37 CR38 CR39 CR40 CR41 CR42 CR43 CR44 CR45 CR46 CR47 CR48 CR49 CR50 CR51 CR52\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e], 33 women) were included, see Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. All three groups were nearly balanced with respect to sex. The average age overall was 41.7 years, with the no-LBP group being about five years younger on average. Pain and disability scores were higher in patients with LBP than in the no-LBP group.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eStudy population characteristics: N, mean, p10, and p90, or absolute frequency and percentage by participant groups.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"9\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGroup\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLBP\u003c/p\u003e\u003cp\u003eNRS\u003c/p\u003e\u003cp\u003e(0\u0026ndash;10)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eLeg pain\u003c/p\u003e\u003cp\u003eNRS\u003c/p\u003e\u003cp\u003e(0\u0026ndash;10)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFABQw\u003c/p\u003e\u003cp\u003e(0\u0026ndash;42)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eRMDQ\u003c/p\u003e\u003cp\u003e(0\u0026ndash;24)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSick leave\u003c/p\u003e\u003cp\u003e(Days/yr)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eBMI\u003c/p\u003e\u003cp\u003e(kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eAge\u003c/p\u003e\u003cp\u003e(Years)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eSex\u003c/p\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLBP only (N)\u003c/p\u003e\u003cp\u003eMean(p10-p90)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e69\u003c/p\u003e\u003cp\u003e5.0(2\u0026ndash;8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e68\u003c/p\u003e\u003cp\u003e1.5(0\u0026ndash;5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e57\u003c/p\u003e\u003cp\u003e11.4(0\u0026ndash;26)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e67\u003c/p\u003e\u003cp\u003e41.4(4.4\u0026ndash;82.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e57\u003c/p\u003e\u003cp\u003e2.1(0\u0026ndash;7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e66\u003c/p\u003e\u003cp\u003e26.8(21.9\u0026ndash;32.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e69\u003c/p\u003e\u003cp\u003e42.1(22\u0026ndash;56)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e34/69\u003c/p\u003e\u003cp\u003e(49.3%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLBP\u0026thinsp;+\u0026thinsp;leg pain (N)\u003c/p\u003e\u003cp\u003eMean(p10-p90)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e88\u003c/p\u003e\u003cp\u003e5.6(2\u0026ndash;8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e88\u003c/p\u003e\u003cp\u003e5.5(2\u0026ndash;8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e78\u003c/p\u003e\u003cp\u003e13.9(1\u0026ndash;25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e86\u003c/p\u003e\u003cp\u003e56.1(21.7\u0026ndash;86.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e78\u003c/p\u003e\u003cp\u003e3.7(0\u0026ndash;15)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e84\u003c/p\u003e\u003cp\u003e27.6(21.8\u0026ndash;34.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e88\u003c/p\u003e\u003cp\u003e45.2(29\u0026ndash;57)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e43/88\u003c/p\u003e\u003cp\u003e(48.9%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNo-LBP (N)\u003c/p\u003e\u003cp\u003eMean(p10-p90)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e48\u003c/p\u003e\u003cp\u003e.4(0\u0026ndash;1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e49\u003c/p\u003e\u003cp\u003e.8(0\u0026ndash;5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e36\u003c/p\u003e\u003cp\u003e3.2(0\u0026ndash;15)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e45\u003c/p\u003e\u003cp\u003e6.2(0\u0026ndash;13.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e62\u003c/p\u003e\u003cp\u003e.1(0\u0026ndash;0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e63\u003c/p\u003e\u003cp\u003e24.1(19.7\u0026ndash;28.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e63\u003c/p\u003e\u003cp\u003e36.4(21\u0026ndash;53)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e33/63\u003c/p\u003e\u003cp\u003e(52.4%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTotal (N)\u003c/p\u003e\u003cp\u003e(mean)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e205\u003c/p\u003e\u003cp\u003e4.2(0\u0026ndash;8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e205\u003c/p\u003e\u003cp\u003e3.0(0\u0026ndash;8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e171\u003c/p\u003e\u003cp\u003e10.8(0\u0026ndash;24)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e198\u003c/p\u003e\u003cp\u003e39.8(0-78.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e197\u003c/p\u003e\u003cp\u003e2.1(0\u0026ndash;7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e213\u003c/p\u003e\u003cp\u003e26.2(21.2\u0026ndash;32.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e220\u003c/p\u003e\u003cp\u003e41.7(22-56.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e110/220\u003c/p\u003e\u003cp\u003e(50.0%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eNRS: Numerical Rating Scale. FABQw: Fear Avoidance Belief Questionnaire (work subscale). RMDQ: Roland Morris Disability Questionnaire.\u003c/p\u003e\u003cp\u003eIn both groups of patients, about half had five or more abnormal MRI findings in the recumbent position. In participants with no-LBP half of the participants had less than two abnormal findings, see Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Pathologies were identified in four participants, all were classified as \"other pathology\" and represented incidental findings, e.g. hemangiomas.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eSupplementary Fig.\u0026nbsp;1 and Supplementary Table\u0026nbsp;1, in Appendix, provide a detailed overview of the frequency of findings in the recumbent position.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Type and frequency of differences observed at the disc level\u003c/h2\u003e\u003cp\u003eOut of 23,478 classifications of potential differences in MRI findings between the two positions at the disc level, the raters noted a difference in 475 (2.02%) of cases, see Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. \u0026ldquo;\u003cem\u003eWorsen\u003c/em\u003e\u0026rdquo; was the most frequent type of difference reported, followed by \u0026ldquo;\u003cem\u003eappear\u003c/em\u003e\u0026rdquo;, together covering nearly 90% of all differences. \u0026ldquo;\u003cem\u003eDisappear\u003c/em\u003e\u0026rdquo; and \u0026ldquo;Improve\u0026rdquo; were both reported in slightly less than 5% of all cases. The raters did not specify the type of difference in 3% of cases. Finding and disk-level specific frequencies can be found in Supplementary Fig.\u0026nbsp;2.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eFrequency of the types of differences between the recumbent and upright positions at the disc level across all MRI findings.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDifference\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFrequency (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAppear\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e187 (39%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDisappear\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e21 ( 4%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWorsen\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e236 (50%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eImprove\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e19 ( 4%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUnspecified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12 ( 3%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eTotal\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e475 (100%)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eOf the 475 differences reported, the certainty of the assessments of 270 (57%) were classified as \u0026ldquo;\u003cem\u003eprobable\u003c/em\u003e\u0026rdquo; and 205 (43%) as \u0026ldquo;\u003cem\u003edefinite\u003c/em\u003e\u0026rdquo;. The latter was chosen most frequently when a difference was classified as \u0026ldquo;\u003cem\u003eappear\u003c/em\u003e\u0026rdquo; (52.9%), followed by \u0026ldquo;\u003cem\u003edisappear\u003c/em\u003e\u0026rdquo; (42.9%), \u0026ldquo;\u003cem\u003eworsen\u003c/em\u003e\u0026rdquo; (38.6%), and finally \u0026ldquo;\u003cem\u003eimprove\u003c/em\u003e\u0026rdquo; (21.0%). The raters used \u0026ldquo;\u003cem\u003edefinite\u003c/em\u003e\u0026rdquo; most frequently at L3 and least frequently at L5. Among the single findings, \u0026ldquo;\u003cem\u003edefinite\u003c/em\u003e\u0026rdquo; was chosen frequently for \u003cem\u003eanteriorlisthesis (87.5%)\u003c/em\u003e and \u003cem\u003escoliosis (68.6%)\u003c/em\u003e, and \u0026ldquo;\u003cem\u003eprobable\u003c/em\u003e\u0026rdquo; was chosen frequently for \u003cem\u003eretrolisthesis (100%)\u003c/em\u003e, \u003cem\u003efacet joint degeneration\u003c/em\u003e (70%), \u003cem\u003enerve root compromise (\u003c/em\u003e73.1%), and \u003cem\u003edisc degeneration\u003c/em\u003e (\u003cem\u003e70.0%).\u003c/em\u003e\u003c/p\u003e\u003cp\u003eDifferences in serious pathologies were not observed for any of the groups and therefore are not included in the subsequent analyses.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Which MRI findings and disc levels are most likely to present a difference?\u003c/h2\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e depicts the frequency of the types of differences for each MRI finding. Overall participant groups (cf. totals at the lower right quadrant of the figure), the highest frequencies were observed for \u003cem\u003edisc contour (21%)\u003c/em\u003e, \u003cem\u003elateral recess stenosis (17%), central spinal stenosis (15%), and annular fissure (15%).\u003c/em\u003e The lowest frequencies were observed for \u003cem\u003espondylolisthesis anterior direction (2.6%)\u003c/em\u003e, \u003cem\u003espondylolisthesis posterior direction (1.7%)\u003c/em\u003e, and \u003cem\u003efacet joint asymmetry\u003c/em\u003e (\u003cem\u003e0.15%\u003c/em\u003e) with \u003cem\u003earcolysis\u003c/em\u003e and \u003cem\u003espondylolisthesis lateral direction\u003c/em\u003e never showing a difference between the two positions. Within each participant group, the highest frequency was observed for \u003cem\u003edisc contour, lateral recess stenosis, central spinal stenosis\u003c/em\u003e, and \u003cem\u003eannular fissure\u003c/em\u003e. Frequencies of differences were generally lower in the no-LBP group. Differences for \u003cem\u003ecentral stenosis\u003c/em\u003e, \u003cem\u003elateral recess stenosis\u003c/em\u003e and \u003cem\u003eannular fissures\u003c/em\u003e were observed more frequently for participants with LBP only than with LPB and leg pain.\u003c/p\u003e\u003cp\u003eWhen relating the frequency of a difference between the two positions to the frequency of an abnormal finding in the recumbent position (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e), the MRI-findings with higher prevalences of abnormal findings in the recumbent position were also observed to be different more frequently in the upright position. However, there seem to be two exceptions to this rule: For \u003cem\u003efacet joint degeneration\u003c/em\u003e and \u003cem\u003edisc degeneration\u003c/em\u003e, differences were observed in less than 5% of the patients despite abnormal findings in more than half of the participants. For s\u003cem\u003ecoliosis\u003c/em\u003e differences were observed in more than 10% of cases despite a frequency of abnormal findings below 10%.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e3.4 What types of impact can be expected at the participant level?\u003c/h2\u003e\u003cp\u003e\u0026ldquo;\u003cem\u003eStaying abnormal\u003c/em\u003e\u0026rdquo; or \u0026ldquo;\u003cem\u003estaying normal\u003c/em\u003e\u0026rdquo; was generally the most common type of impact at the participant level (70\u0026ndash;80%) when summarizing MRI findings across the three disc levels, see Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. For those findings with a sufficient frequency of differences, both completely new appearances (\u0026ldquo;\u003cem\u003enew\u003c/em\u003e\u0026rdquo;), a broadening across more disc levels (\u0026ldquo;\u003cem\u003ebroader\u0026rdquo;\u003c/em\u003e), and (only) a worsening of findings across already identified disc levels (\u0026ldquo;\u003cem\u003eworsened\u0026rdquo;\u003c/em\u003e) could be observed. For \u003cem\u003edisc contour, \u0026ldquo;worsened\u003c/em\u003e\u0026rdquo; was by far the most frequent type of difference (up to 20%), and for \u003cem\u003escoliosis\u003c/em\u003e \u0026ldquo;\u003cem\u003enew\u003c/em\u003e\u0026rdquo; could account for more than 50% of differences, and \u0026ldquo;\u003cem\u003ebroader\u003c/em\u003e\u0026rdquo; was never observed. Otherwise, the distribution across these three types of differences was almost balanced. For both \u003cem\u003edisc-\u003c/em\u003e and \u003cem\u003efacet joint degeneration\u003c/em\u003e change frequencies were never above 5%, and almost entirely seen as \u0026ldquo;\u003cem\u003eworsened\u0026rdquo;. \u0026ldquo;Vanished\u0026rdquo;, \u0026ldquo;more narrow\u0026rdquo;, and \u0026ldquo;improved\u0026rdquo;\u003c/em\u003e were usually very rare. Generally, \u0026ldquo;\u003cem\u003evanished\u003c/em\u003e\u0026rdquo; was only observed for \u003cem\u003eannular fissures\u003c/em\u003e, and this was the only finding where nine of the 10 possible types of difference were observed.\u003c/p\u003e\u003cp\u003eSupplementary Figs.\u0026nbsp;3A and 3B in the Appendix provides information about the impact at the participant level when summarizing across all findings or across all findings and levels. According to Supplementary Figs.\u0026nbsp;3A, disc level L4 presented the most differences between the two positions. At this level nearly 30% of discs showed MRI-findings that either appeared or worsened, compared to approximately 15% at L3 and L5 levels. Seven percent of MRI findings either improved or disappeared at the L4 level compared to 5% at L3 and L5 levels.\u003c/p\u003e\u003cp\u003e3.5 How many findings with a difference between recumbent and upright MRI can be expected in a participant?\u003c/p\u003e\u003c/p\u003e\u003cp\u003eOverall, differences in one or more MRI findings were seen in about half of the participants in the two patient groups and in about one-third of the participants in the no-LBP group, see Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. In approximately one-third of the participants in the two LBP groups, differences were seen for two or more MRI findings compared to a little more than 10% among participants with no-LBP.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eIn all three groups, the number of MRI findings that differed between the two positions was positively associated with the number of \u0026ldquo;\u003cem\u003eabnormal\u0026rdquo;\u003c/em\u003e findings in the recumbent position, see Supplementary Fig.\u0026nbsp;4. When stratified by the number of \u0026ldquo;\u003cem\u003eabnormal\u0026rdquo;\u003c/em\u003e findings, no substantial difference between the three participant groups could be observed, see Supplementary Fig.\u0026nbsp;5.\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003e4.1 Summary of results\u003c/h2\u003e\u003cp\u003eThis study conducted a direct comparison of common lumbar MRI findings in the recumbent versus upright position, analyzing a series of 22 distinct MRI features across three disc levels. The results led to three new key insights:\u003c/p\u003e\u003cp\u003e\u003col\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003ePrevalence of Positional Differences: In approximately half of all LBP patients, at least one positional difference was observed\u0026mdash; and typically there were several differences in a patient. A smaller proportion of differences between the two positions was seen in individuals without LBP.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eVariability Across MRI Findings: The frequency of positional differences varied substantially between MRI findings. This variation cannot be fully explained by the frequency of abnormalities observed in the recumbent position.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eEnhanced Diagnostic Insight: The use of both positions offers a more comprehensive and nuanced understanding of the lumbar spine, allowing for a more refined and richer impression in a substantial number of patients.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e\u003cp\u003eIn the following we further elaborate on these key findings and highlight specific observations.\u003c/p\u003e\u003cp\u003e\u003cb\u003eNature and direction of positional differences\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWhen positional differences occurred in the upright position, they were typically unfavorable for the patient. In most cases, positional differences meant upgrading of findings, involvement of additional discs levels or appearance of new findings. Downgrading or vanishing of findings were rather rare and mostly limited to \u003cem\u003eannular fissures\u003c/em\u003e.\u003c/p\u003e\u003cp\u003eIn interpreting the fact that there was at least one difference in half of the patients (and typically more than one difference), it should be noted that it is correct to interpret a difference mainly as a move towards a less favorable situation. On the other hand, the occurrence of such differences should not be misinterpreted as a dramatic change from a completely normal MRI to some abnormal MRI at the participant level. Such a change is very rare \u0026ndash; which is simply a consequence of the fact that most patients had at least one abnormal finding in the recumbent position.\u003c/p\u003e\u003cp\u003eNotably, for disc contour differences, 75% of observed differences represented upgrading of pre-existing findings, indicating that upright MRI may be particularly valuable for assessing the severity at specific levels rather than in detecting new instances at other disc levels. This is consistent with radiographic findings, where disc height reduction is more pronounced in the upright position (32) due to impaired disc resilience under load(33; 34). In contrast, \u003cem\u003e\u0026ldquo;new\u0026rdquo;\u003c/em\u003e accounted for more than 50% of the differences in \u003cem\u003escoliosis\u003c/em\u003e as already discussed above.\u003c/p\u003e\u003cp\u003e\u003cb\u003eRelationship between abnormalities and positional differences\u003c/b\u003e\u003c/p\u003e\u003cp\u003eOnly already abnormal finding\u003cem\u003es\u003c/em\u003e present in the recumbent position can show differences such as \u0026ldquo;\u003cem\u003eworsened\u0026rdquo;\u003c/em\u003e, \u003cem\u003e\u0026ldquo;improved\u0026rdquo;\u003c/em\u003e, or \u003cem\u003e\u0026ldquo;disappeared\u0026rdquo;\u003c/em\u003e in the upright position. Therefore, the frequency of positional differences is inherently linked to the baseline prevalence of abnormalities as actually observed in this study. However, some findings deviated from this trend. For instance, despite being \u003cem\u003e\u0026ldquo;abnormal\u0026rdquo;\u003c/em\u003e in more than half of the patients in the recumbent position, \u003cem\u003edisc degeneration\u003c/em\u003e and \u003cem\u003efacet degeneration\u003c/em\u003e showed rather rarely differences with position, possibly indicating that only advanced cases exhibit positional effects.\u003c/p\u003e\u003cp\u003eReversely, \u003cem\u003escoliosis \u0026ldquo;appeared\u0026rdquo;\u003c/em\u003e or \u0026ldquo;\u003cem\u003eworsened\u0026rdquo;\u003c/em\u003e in almost 10% of all participants, despite a prevalence of only 7% in the recumbent position. This may reflect the dynamic nature of the spine where curves are likely to be more \u0026ldquo;natural\u0026rdquo; in the weight-bearing(35). Also, some participants may have a pain-induced deviation of the lumbar spine rather than true \u003cem\u003escoliosis\u003c/em\u003e and that this pain-induced deviation is increased in the upright position.\u003c/p\u003e\u003cp\u003e\u003cb\u003eInterpretation of variability\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWhile variation in the frequency of differences across MRI findings has been reported in previous studies (8), cross-study comparisons are often biased due to differences in patient populations. Our study allowed for the first time an unbiased comparison of frequencies across many findings using a consistent cohort and uniquely demonstrates that positional differences were most seen in \u003cem\u003edisc contour\u003c/em\u003e changes (\u003cem\u003ebulge, protrusion, extrusion\u003c/em\u003e), \u003cem\u003eannular fissures\u003c/em\u003e, and \u003cem\u003espinal stenoses (central canal, lateral recess, foraminal)\u003c/em\u003e. In contrast, differences in \u003cem\u003espondylolisthesis\u003c/em\u003e, \u003cem\u003edisc degeneration\u003c/em\u003e, and \u003cem\u003efacet joint degeneration\u003c/em\u003e were rare. The absence of differences for spondylolistheses in the lateral direction could be due to limited coronal sequences available in the upright position (only one coronal scout image) compared to the recumbent position where more coronal images were available. Also, spondylolysis can be challenging to identify on MRI, in general, and on low field MRI in particular.\u003c/p\u003e\u003cp\u003eIn general, the existence of differences corroborated the choice of MRI-findings, which was driven by the expectation to observe differences in at least some patients \u0026ndash; except for \u003cem\u003eserious pathology\u003c/em\u003e and \u003cem\u003efacet joint asymmetry\u003c/em\u003e. Indeed, a new suspicion of a \u003cem\u003eserious pathology\u003c/em\u003e was never observed in the upright position, and a difference in \u003cem\u003efacet joint asymmetry\u003c/em\u003e was observed only in one patient.\u003c/p\u003e\u003cp\u003e\u003cb\u003eGroup comparisons\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe study included three participant groups. No-LBP individuals showed fewer differences, likely due to fewer baseline abnormalities. Among LBP patients, those without leg pain exhibited more frequent differences in central and lateral recess stenosis and nerve root compromise compared to those with leg pain. This may be due to the latter group already presenting with more severe stenoses in the recumbent position, leaving less room for further change upon weight-bearing. Supplementary Table\u0026nbsp;2 confirms that LBP patients with leg pain had a higher prevalence of absolute stenosis.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\u003ch2\u003e4.2 Comparison with the literature\u003c/h2\u003e\u003cp\u003eAs indicated by a recent systematic review of recumbent vs upright MRI of the lumbar spine, most previous investigations evaluated the two positions independently (8). Thus, direct comparisons with other studies are challenging due to this methodological difference. Hansen et al. is a notable exception, using an approach like ours(16). For five out of seven comparable findings, their results aligned with ours; however, they reported far fewer differences in disc contour and annular fissures. Detailed comparisons are available in Supplementary Table\u0026nbsp;2.\u003c/p\u003e\u003cp\u003eIn addition, previous studies have often reported positional MRI differences as rare, particularly in reproducibility studies where raters tend to be more conservative(7; 16). This contrasts with our findings, where half of LBP patients demonstrated at least one difference, and one-third showed two or more. This discrepancy may stem from earlier studies focusing on fewer MRI parameters, whereas our study evaluated a broader set of 22 MRI findings in all participants.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003e4.3 Clinical and research impact\u003c/h2\u003e\u003cp\u003eThe findings of this study suggest that upright MRI may offer greater clinical value in the evaluation of low back pain than previously recognized. In contrast to earlier studies that focused on only a few imaging features, our comprehensive assessment revealed that positional differences were present in at least one MRI finding in half of all LBP patients. Upright imaging provides a more nuanced view of the lumbar spine revealing additional affected disc levels, making certain abnormalities more visible, or demonstrating increased severity of existing findings. However, it is uncommon for upright MRI to reveal \u003cem\u003eonly\u003c/em\u003e new findings, as signs of degeneration are generally already detectable in recumbent scans.\u003c/p\u003e\u003cp\u003eThe clinical value of this additional information is still to be investigated, especially the impact of upright MRI findings on clinical decisions and patient outcomes. Some insights can\u003c/p\u003e\u003cp\u003ebe obtained by studying whether differences in MRI findings between the two positions correlate, or improve the correlation, with patient-reported symptoms\u0026mdash;both localized LBP and radiating leg pain. Further insights can be obtained from studying the impact of adding a recumbent MRI on management decisions and on the satisfaction of patients with respect to understanding their disease status. When it is clarified how clinicians can make the best use of the additional information, the benefit of adding an upright MRI can ultimately be investigated in randomized controlled trials assessing patient outcomes.\u003c/p\u003e\u003cp\u003eInterestingly, our results showed that findings classified as \u0026ldquo;disappeared\u0026rdquo; were rare and mostly limited to annular fissures \u0026ndash; a finding of limited clinical relevance (36). This raises the possibility that upright MRI might eventually \u003cem\u003ereplace\u003c/em\u003e rather than complement recumbent imaging in selected cases. Our study did not reveal clinically important findings that were missed in the upright position. However, a combined approach may still be preferred, as positional shifts can offer insights into pain mechanisms (e.g., dynamic instability), which would be lost if only one position was assessed.\u003c/p\u003e\u003cp\u003eThis study also reinforces the well-documented finding that MRI abnormalities may be present in asymptomatic individuals. Upright MRI enhances the visibility of degenerative differences not only in symptomatic patients but also in those without current LBP. Thus, it may aid in early detection of potentially pain-generating changes before symptom onset. Recent systematic reviews suggest that certain MRI features can predict future LBP and disability in asymptomatic patients, further emphasizing the potential prognostic value of upright imaging (37).\u003c/p\u003e\u003cp\u003eTo capture diagnostic uncertainty, raters were allowed to classify observed differences as either \u0026ldquo;probable\u0026rdquo; or \u0026ldquo;definite.\u0026rdquo; Over half of the differences were labeled \u0026ldquo;probable,\u0026rdquo; highlighting the inherent challenges in evaluating positional differences. This grading system proved useful, especially since \u0026ldquo;\u003cem\u003eworsened\u003c/em\u003e\u0026rdquo; and \u0026ldquo;\u003cem\u003eimproved\u003c/em\u003e\u0026rdquo; findings were rated as more difficult to assess than \u0026ldquo;\u003cem\u003eappeared\u003c/em\u003e\u0026rdquo; or \u0026ldquo;\u003cem\u003edisappeared\u003c/em\u003e\u0026rdquo; findings. Unsurprisingly, disc level L5 posed the greatest interpretive challenges, followed by L4 and L3, likely due to its transitional anatomy and technical imaging difficulties. We recommend incorporating similar confidence assessments in future studies.\u003c/p\u003e\u003cp\u003eIn designing the assessment procedure, we made use of established criteria to evaluate single findings. It can be only speculated to which degree this has facilitated the findings of this study. To improve diagnostic accuracy and consistency, we regarded consensus-based criteria as essential for interpreting upright MRI. We recommend the use of standardized classification systems such as those proposed by Fardon et al. to improve reproducibility and diagnostic confidence(28).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e\u003ch2\u003e4.4 Limitations of the study\u003c/h2\u003e\u003cp\u003eThis study involved three raters, and a subset of 59 out of 220 participants was assessed by all raters for reliability analysis. Previous findings from this reliability study indicated greater inter-rater consistency for negative assessments compared to positive ones, and differences in rater thresholds for identifying abnormalities were observed(7). Such variability may limit the generalizability of our findings, although similar challenges have been reported in prior research(16).\u003c/p\u003e\u003cp\u003eThe selection and classification of MRI findings were predefined during the study planning phase. The assessment protocol, requiring 1\u0026ndash;2 hours per participant depending on complexity, necessitated a limit on the number of features evaluated. Some potentially informative markers, such as Modic changes, disc bulging in the upright position, and ligamentum flavum contributions, were excluded. While these omissions may be viewed as limitations, they were necessary to ensure feasibility. Additionally, the ordinal classification system used to describe differences (e.g., \u0026ldquo;\u003cem\u003eworsened\u003c/em\u003e,\u0026rdquo; \u0026ldquo;\u003cem\u003eappeared\u003c/em\u003e\u0026rdquo;) may have resulted in a loss of information. Quantitative measures such as angles or distances could provide more precise assessments but would have added considerable time and complexity.\u003c/p\u003e\u003cp\u003eLastly, a potential source of bias was introduced by differences in imaging equipment. Participants outside the clinical referral pathway received recumbent scans on a 0.5T open MRI system, which differed in image quality and sequence parameters from those used for the other groups. As a result, raters may have been able to infer participant group membership, possibly leading to underreporting findings in asymptomatic individuals. We do not regard the use of a low field strength of 0.5T in the recumbent position in non-LBP patients as a problem in itself, as longer scanning times still allow us to obtain a proper image quality. In contrast, in the upright position the use of such low field strength and hence longer scanning times must be expected to have an impact on the image quality due to possible movements of the patient.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003e4.5 Outlook\u003c/h2\u003e\u003cp\u003eAn upright MRI has to be seen as a promising modality due to its potential diagnostic gain, which still must demonstrate its clinical benefit for patients in well-designed studies. This requires careful considerations about its clinical use. As this study was based on unselected patient cohorts with or without suspected degenerative disease, we investigated the potential value when using upright MRI together with recumbent MRI as a first-choice modality. However, in the future we mainly see a role for upright MRI in LBP patients, where the patient history and clinical findings seem to mismatch the diagnostic imaging findings initially found in conventional recumbent MRI. Image quality may also be an issue to be solved by progress in image processing, as movement of patients can be less controlled in upright MRI. In any case, a potential benefit must be balanced against potential increased costs and stress to patients, as an upright MRI is more time-consuming to perform and may induce discomfort. Hence finally, careful risk-benefit and cost-benefit analyses will be necessary.\u003c/p\u003e\u003cp\u003eIt can only be hoped that the research interest in upright MRI is increased to clarify its role in clinical practice, which then may be followed by an increased use in clinical practice or its abolishment.\u003c/p\u003e\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eDirect comparison of a series of common lumbar MRI findings in the recumbent versus the upright positions, shows a systematic increase in findings in the upright position, compared to the recumbent position and may add more information regarding lumbar spine pathology than previously suggested by studies investigating only single or few findings. Further research is needed to investigate the clinical value of upright MRI.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eLBP\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Low Back Pain\u003c/p\u003e\n\u003cp\u003eSTROBE \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;STrengthening the Reporting of OBservational studies in Epidemiology\u003c/p\u003e\n\u003cp\u003eREDCap \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Research Electronic Data Capture\u003c/p\u003e\n\u003cp\u003eNRS \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Numerical Rating Scale\u003c/p\u003e\n\u003cp\u003eFABQ \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Fear Avoidance Belief Questionnaire\u003c/p\u003e\n\u003cp\u003eRMDQ\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Roland Morris Disability Questionnaire\u003c/p\u003e\n\u003cp\u003eBMI \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Body Mass Index\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e5.1 Clinical trial number:\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e5.2 Ethics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eWritten informed consent was obtained from all participants in this project. Local ethics committee approval was not required due to the methodological nature of the study according to Danish law: \u0026sect; 14, piece 1 in law on scientific ethical handling of health scientific research projects. A letter of exemption from the Scientific Ethics Committee in Region Southern Denmark, Damhaven 12, 7100 Vejle, Denmark, is available from the author on request (case numbers 48336/S-20172000-96). The Danish Data Protection Agency has also approved the project under reference number 2015-414037. All procedures performed in studies involving human subjects were in accordance with the ethical standards of the institutional and/or national research committee and with the Helsinki Declaration of 1964 and its subsequent amendments or comparable ethical standards.\u003c/p\u003e\n\u003cp\u003e5.3 Consent for publication\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e5.4 Availability of data and materials\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e5.5 Competing interests\u003c/p\u003e\n\u003cp\u003eThe authors declared that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e5.6 Funding\u003c/p\u003e\n\u003cp\u003eFunding was provided from the Foundation for Advancement of Chiropractic Research and Postgraduate Education in Denmark and AGFA HealthCare, Belgium. The funders did not have a role in role in the conceptualization, design, data collection, analysis, decision to publish, or preparation of the manuscript.\u003c/p\u003e\n\u003cp\u003e5.7 Authors\u0026apos; contributions\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAll authors:\u003c/strong\u003e made substantial contribution to the conception, approved the submitted manuscript and agreed to be personally accountable for the authors own contribution and to ensure that questions related to the accuracy or integrity of any part of the work, even ones in which the author was not personally involved, are appropriately investigated, resolved, and the resolution documented in the literature. Individual contributions: \u003cstrong\u003eKlaus Doktor\u003c/strong\u003e \u0026ndash; design; acquisition, analysis and interpretation of data; drafted the work or substantively revised it. \u003cstrong\u003eWerner Vach\u003c/strong\u003e - design; acquisition; analysis and interpretation of data; drafted the work or substantively revised it. \u003cstrong\u003eLau Brix\u003c/strong\u003e - drafted the work or substantively revised it. \u003cstrong\u003eMark Hancock\u003c/strong\u003e - interpretation of data; drafted the work or substantively revised it. \u003cstrong\u003eJan Hartvigsen\u003c/strong\u003e - design; interpretation of data; drafted the work or substantively revised it. \u003cstrong\u003eTue Secher Jensen\u003c/strong\u003e - design; acquisition, analysis and interpretation of data; drafted the work or substantively revised it.\u003c/p\u003e\n\u003cp\u003e5.8 Acknowledgements\u003c/p\u003e\n\u003cp\u003eThe authors would like to thank radiographers and others participating in the organization of the project: Annette Kryger Jensen, Jonas Knudsen, Birgitte Hornb\u0026aelig;k Korsholm, Maria Jendritska Randlev, Brian H\u0026oslash;jgaard, and Hanne la Cour Ginnerup, Diagnostic Centre, Silkeborg Regional Hospital; Orla Lund Nielsen, Chiropractic Knowledge Hub, and University of Southern Denmark, for support in data handling. Line Thorndal Moll, Department of Public Health, Aarhus University, Denmark, kindly shared her research.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eWang YXJ, Wu AM, Ruiz Santiago F, Nogueira-Barbosa MH. 2018. Informed appropriate imaging for low back pain management: A narrative review. \u003cem\u003eJ Orthop Translat\u003c/em\u003e 15:21-34\u003c/li\u003e\n\u003cli\u003evan der Graaf JW, Kroeze RJ, Buckens CFM, Lessmann N, van Hooff ML. 2023. MRI image features with an evident relation to low back pain: a narrative review. \u003cem\u003eEuropean Spine Journal\u003c/em\u003e 32:1830-41\u003c/li\u003e\n\u003cli\u003eBrinjikji W, Luetmer PH, Comstock B, Bresnahan BW, Chen LE, et al. 2015. Systematic literature review of imaging features of spinal degeneration in asymptomatic populations. \u003cem\u003eAJNR. American journal of neuroradiology\u003c/em\u003e 36:811-6\u003c/li\u003e\n\u003cli\u003eAlyas F, Connell D, Saifuddin A. 2008. Upright positional MRI of the lumbar spine. \u003cem\u003eClin Radiol\u003c/em\u003e 63:1035-48\u003c/li\u003e\n\u003cli\u003eSplendiani A, Perri M, Grattacaso G, Di Tunno V, Marsecano C, et al. 2016. Magnetic resonance imaging (MRI) of the lumbar spine with dedicated G-scan machine in the upright position: a retrospective study and our experience in 10 years with 4305 patients. \u003cem\u003eRadiol Med\u003c/em\u003e 121:38-44\u003c/li\u003e\n\u003cli\u003eTarantino U, Fanucci E, Iundusi R, Celi M, Altobelli S, et al. 2013. Lumbar spine MRI in upright position for diagnosing acute and chronic low back pain: statistical analysis of morphological changes. \u003cem\u003eJournal of orthopaedics and traumatology : official journal of the Italian Society of Orthopaedics and Traumatology\u003c/em\u003e 14:15-22\u003c/li\u003e\n\u003cli\u003eDoktor K, Hartvigsen J, Hancock M, Christensen HW, Fredberg U, et al. 2022. Reliability of reporting differences in degenerative MRI findings of the lumbar spine from the supine to the upright position. \u003cem\u003eSkeletal Radiol\u003c/em\u003e\u003c/li\u003e\n\u003cli\u003eDoktor K, Christensen HW, Jensen TS, Hancock MJ, Vach W, Hartvigsen J. 2025. Upright versus recumbent lumbar spine MRI: Do findings differ systematically, and which correlates better with pain? A systematic review. \u003cem\u003eSpine J\u003c/em\u003e\u003c/li\u003e\n\u003cli\u003evon Elm E, Altman DG, Egger M, Pocock SJ, Gotzsche PC, et al. 2014. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: guidelines for reporting observational studies. \u003cem\u003eInt J Surg\u003c/em\u003e 12:1495-9\u003c/li\u003e\n\u003cli\u003eHarris PA, Taylor R, Minor BL, Elliott V, Fernandez M, et al. 2019. The REDCap consortium: Building an international community of software platform partners. \u003cem\u003eJournal of Biomedical Informatics\u003c/em\u003e 95:103208\u003c/li\u003e\n\u003cli\u003eHarris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. 2009. Research electronic data capture (REDCap)\u0026mdash;A metadata-driven methodology and workflow process for providing translational research informatics support. \u003cem\u003eJournal of Biomedical Informatics\u003c/em\u003e 42:377-81\u003c/li\u003e\n\u003cli\u003eSplendiani A, Bruno F, Marsecano C, Arrigoni F, Di Cesare E, et al. 2019. Modic I changes size increase from supine to standing MRI correlates with increase in pain intensity in standing position: uncovering the \u0026quot;biomechanical stress\u0026quot; and \u0026quot;active discopathy\u0026quot; theories in low back pain. \u003cem\u003eEur Spine J\u003c/em\u003e 28:983-92\u003c/li\u003e\n\u003cli\u003eNordberg CL, Boesen M, Fournier GL, Bliddal H, Hansen P, Hansen BB. 2021. Positional changes in lumbar disc herniation during standing or lumbar extension: a cross-sectional weight-bearing MRI study. \u003cem\u003eEuropean radiology\u003c/em\u003e 31:804-12\u003c/li\u003e\n\u003cli\u003eIbrahim H, Diab K. 2021. Unexplained back pain and sciatica: the added value of upright dynamic MRI of the lumbar spine in cases of clinical/radiological mismatch. \u003cem\u003eEgypt J Radiol Nucl Med\u003c/em\u003e 52\u003c/li\u003e\n\u003cli\u003eMuto M, Giurazza F, Guarnieri G, Senese R, Schena E, et al. 2016. Dynamic MR in patients affected by neurogenical claudication: technique and results from a single-center experience. \u003cem\u003eNeuroradiology\u003c/em\u003e 58:765-70\u003c/li\u003e\n\u003cli\u003eHansen BB, Hansen P, Christensen AF, Trampedach C, Rasti Z, et al. 2018. Reliability of standing weight-bearing (0.25T) MR imaging findings and positional changes in the lumbar spine. \u003cem\u003eSkeletal Radiol\u003c/em\u003e 47:25-35\u003c/li\u003e\n\u003cli\u003eSplendiani A, Ferrari F, Barile A, Masciocchi C, Gallucci M. 2014. Occult neural foraminal stenosis caused by association between disc degeneration and facet joint osteoarthritis: demonstration with dedicated upright MRI system. \u003cem\u003eRadiol Med\u003c/em\u003e 119:164-74\u003c/li\u003e\n\u003cli\u003eDoktor K, Jensen TS, Christensen HW, Fredberg U, Kindt M, et al. 2020. Degenerative findings in lumbar spine MRI: an inter-rater reliability study involving three raters. \u003cem\u003eChiropr Man Therap\u003c/em\u003e 28:8\u003c/li\u003e\n\u003cli\u003ePfirrmann CW, Metzdorf A, Zanetti M, Hodler J, Boos N. 2001. Magnetic resonance classification of lumbar intervertebral disc degeneration. \u003cem\u003eSpine (Phila Pa 1976)\u003c/em\u003e 26:1873-8\u003c/li\u003e\n\u003cli\u003eAprill C, Bogduk N. 1992. High-intensity zone: a diagnostic sign of painful lumbar disc on magnetic resonance imaging. \u003cem\u003eBr J Radiol\u003c/em\u003e 65:361-9\u003c/li\u003e\n\u003cli\u003eLee S, Lee JW, Yeom JS, Kim KJ, Kim HJ, et al. 2010. A practical MRI grading system for lumbar foraminal stenosis. \u003cem\u003eAJR Am J Roentgenol\u003c/em\u003e 194:1095-8\u003c/li\u003e\n\u003cli\u003eWildermuth S, Zanetti M, Duewell S, Schmid MR, Romanowski B, et al. 1998. Lumbar spine: quantitative and qualitative assessment of positional (upright flexion and extension) MR imaging and myelography. \u003cem\u003eRadiology\u003c/em\u003e 207:391-8\u003c/li\u003e\n\u003cli\u003eModic MT, Masaryk TJ, Ross JS, Carter JR. 1988. Imaging of degenerative disk disease. \u003cem\u003eRadiology\u003c/em\u003e 168:177-86\u003c/li\u003e\n\u003cli\u003eMeyerding HW. 1956. Spondylolisthesis; surgical fusion of lumbosacral portion of spinal column and interarticular facets; use of autogenous bone grafts for relief of disabling backache. \u003cem\u003eJ Int Coll Surg\u003c/em\u003e 26:566-91\u003c/li\u003e\n\u003cli\u003eGoldstein LA, Waugh TR. 1973. Classification and terminology of scoliosis. \u003cem\u003eClin Orthop Relat Res\u003c/em\u003e:10-22\u003c/li\u003e\n\u003cli\u003eCobb JR. 1958. Scoliosis; quo vadis. \u003cem\u003eThe Journal of bone and joint surgery. American volume\u003c/em\u003e 40-A:507-10\u003c/li\u003e\n\u003cli\u003eCarrino JA, Lurie JD, Tosteson AN, Tosteson TD, Carragee EJ, et al. 2009. Lumbar spine: reliability of MR imaging findings. \u003cem\u003eRadiology\u003c/em\u003e 250:161-70\u003c/li\u003e\n\u003cli\u003eFardon DF, Williams AL, Dohring EJ, Murtagh FR, Gabriel Rothman SL, Sze GK. 2014. Lumbar disc nomenclature: version 2.0: Recommendations of the combined task forces of the North American Spine Society, the American Society of Spine Radiology and the American Society of Neuroradiology. \u003cem\u003eSpine J\u003c/em\u003e 14:2525-45\u003c/li\u003e\n\u003cli\u003eRoss JS, Moore KR. 2015. \u003cem\u003eDiagnostic Imaging Spine\u003c/em\u003e. Philadelphia, PA 19103-2899: Elsevier\u003c/li\u003e\n\u003cli\u003ePathria M. 2005. Imaging of spine instability. \u003cem\u003eSeminars in musculoskeletal radiology\u003c/em\u003e 9:88-99\u003c/li\u003e\n\u003cli\u003eKjaer P, Leboeuf-Yde C, Korsholm L, Sorensen JS, Bendix T. 2005. Magnetic resonance imaging and low back pain in adults: A diagnostic imaging study of 40-year-old men and women. \u003cem\u003eSpine (Philadelphia, Pa. 1976)\u003c/em\u003e 30:1173-80\u003c/li\u003e\n\u003cli\u003eSon S, Lee SG, Kim WK, Ahn Y, Jung JM. 2021. Disc height discrepancy between supine and standing positions as a screening metric for discogenic back pain in patients with disc degeneration. \u003cem\u003eSpine J\u003c/em\u003e 21:71-9\u003c/li\u003e\n\u003cli\u003eSaleem S, Aslam HM, Rehmani MA, Raees A, Alvi AA, Ashraf J. 2013. Lumbar disc degenerative disease: disc degeneration symptoms and magnetic resonance image findings. \u003cem\u003eAsian Spine J\u003c/em\u003e 7:322-34\u003c/li\u003e\n\u003cli\u003eWeiler C, Lopez-Ramos M, Mayer HM, Korge A, Siepe CJ, et al. 2011. Histological analysis of surgical lumbar intervertebral disc tissue provides evidence for an association between disc degeneration and increased body mass index. \u003cem\u003eBMC Res Notes\u003c/em\u003e 4:497\u003c/li\u003e\n\u003cli\u003eMauch F, Jung C, Huth J, Bauer G. 2010. Changes in the lumbar spine of athletes from supine to the true-standing position in magnetic resonance imaging. \u003cem\u003eSpine (Phila Pa 1976)\u003c/em\u003e 35:1002-7\u003c/li\u003e\n\u003cli\u003eBrinjikji W, Diehn FE, Jarvik JG, Carr CM, Kallmes DF, et al. 2015. MRI Findings of Disc Degeneration are More Prevalent in Adults with Low Back Pain than in Asymptomatic Controls: A Systematic Review and Meta-Analysis. \u003cem\u003eAJNR. American journal of neuroradiology\u003c/em\u003e\u003c/li\u003e\n\u003cli\u003eHan CS, Maher CG, Steffens D, Diwan A, Magnussen J, et al. 2023. Some magnetic resonance imaging findings may predict future low back pain and disability: a systematic review. \u003cem\u003eJ Physiother\u003c/em\u003e 69:79-92\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table 2","content":"\u003cp\u003eTable 2 is available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Upright MRI, Weight-bearing MRI, Lumbar spine, Low back pain","lastPublishedDoi":"10.21203/rs.3.rs-8010874/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8010874/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRecumbent MRI is the most widely used image modality in people with low back pain, however, it has been proposed that upright (standing) MRI has advantages over recumbent MRI because of its ability to assess the effects of being weight-bearing and thus, potentially add clinically helpful information.\u003c/p\u003e\n\u003cp\u003eThe aim of this study was to investigate the types and frequencies of differences in lumbar MRI findings, between the recumbent and upright positions, both at the disc level as well as at the participant level.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis prospective observational study included a total of 220 individuals, 69 low back pain patients without leg pain, 88 patients with low back pain and leg pain, and 63 no-LBP patients.\u003c/p\u003e\n\u003cp\u003eAll participants were first scanned in the recumbent position using 0.5T, 1.5T or 3T MRI units, and then scanned in the upright position using an open 0.5T unit. For a series of 22 common MRI findings of the lumbar spine, differences between the two positions were assessed by direct comparison. Types of differences were classified as “\u003cem\u003eappeared\u003c/em\u003e”, “\u003cem\u003edisappeared\u003c/em\u003e”, “\u003cem\u003eworsened\u003c/em\u003e”, or “\u003cem\u003eimproved\u003c/em\u003e” from the recumbent to the upright position, and separately at the disc levels L3/L4, L4/L5, L5/S1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDifferences in at least one MRI finding could be observed in about half of all low back pain patients and in one-third of participants without back pain.\u003c/p\u003e\n\u003cp\u003eAt the participant level, upgrading of findings, involvement of other discs, or appearance of new findings could be observed rather frequently, whereas downgrading, narrowing or vanishing was rare.\u003c/p\u003e\n\u003cp\u003eDifferences were most frequently observed for disc contour (bulge, protrusion, extrusion), lateral recess stenosis, central canal stenosis and annular fissure, and for findings at the L4/L5 disc level.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDirect comparison of a series of common lumbar MRI findings between the recumbent and the upright position, shows a systematic increase in findings in the upright position. This gives a more detailed and nuanced overall picture of the lumbar spine than previously suggested by studies investigating only single or few findings. The clinical value of this additional information requires further investigation.\u003c/p\u003e","manuscriptTitle":"Lumbar MRI findings in the recumbent and the upright position A prospective observational study on type and frequency of differences by direct comparison","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-19 11:50:58","doi":"10.21203/rs.3.rs-8010874/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-29T13:18:22+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"240763400863330645744127664336717235886","date":"2025-12-23T10:46:02+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-18T12:27:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"220394096481665996557752476700279495307","date":"2025-12-18T10:36:20+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-03T09:33:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"315814858494511146370427254845551863192","date":"2025-11-29T18:00:01+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-20T20:39:27+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"183541067212251265695418793914317124024","date":"2025-11-10T08:33:53+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"74979413813120017514290259956555037717","date":"2025-11-09T16:20:57+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-09T15:34:06+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-09T15:30:36+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-11-07T17:52:18+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-07T12:25:26+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Musculoskeletal Disorders","date":"2025-11-07T12:20:54+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a3944906-3b57-49fc-8053-9cd86a2aac90","owner":[],"postedDate":"November 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-05-14T13:39:52+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-19 11:50:58","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8010874","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8010874","identity":"rs-8010874","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}