Diagnostic Accuracy of Magnetic Resonance Imaging versus Computed Tomography for Lumbar Spondylolysis in Patients with Chronic Low Back Pain: A Single-Center Retrospective Study

Diagnostic Accuracy of Magnetic Resonance Imaging versus Computed Tomography for Lumbar Spondylolysis in Patients with Chronic Low Back Pain: A Single-Center Retrospective Study | 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 Diagnostic Accuracy of Magnetic Resonance Imaging versus Computed Tomography for Lumbar Spondylolysis in Patients with Chronic Low Back Pain: A Single-Center Retrospective Study Ahmet TEZCE, Emin DURMUŞ This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9247900/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Purpose The objective of this study is to compare the diagnostic efficacy of Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) in detecting lumbar spondylolysis among patients presenting with chronic low back pain, and to determine the rate of missed diagnoses when MRI is reported as "normal". Methods Radiological images of 2,104 patients who presented with chronic low back pain between December 2024 and December 2025 and underwent simultaneous lumbar CT and MRI were retrospectively reviewed. The study group comprised 67 patients diagnosed with spondylolysis based on CT findings, which served as the gold standard. Demographic characteristics, affected spinal levels, presence of degeneration, and MRI findings (classified as no findings, suspicious findings, or definitive findings) were analyzed. Results The prevalence of spondylolysis in the screened population was 3.18%. The mean age of the study cohort was 46.7 ± 11.2 years, with a female predominance (71.6%). The most frequently affected level was L5-S1 (82.1%). In the retrospective MRI evaluation of patients with a definitive CT diagnosis, 41.8% exhibited no pathological signal alterations (such as edema or fracture lines) in the pars interarticularis. Furthermore, an analysis of the hospital registry revealed that the diagnosis of spondylolysis was completely missed (100%) in all routine MRI reports. The rate of missed diagnosis on MRI was significantly higher in younger patients without degenerative changes (51%) compared to those with concomitant degeneration (31%). Conclusion Routine MRI evaluations yield a high rate of false-negative results in the diagnosis of lumbar spondylolysis. A "normal" MRI report is insufficient to rule out spondylolysis, particularly in younger patients lacking degenerative changes. In cases where clinical suspicion persists, CT imaging must be incorporated into the diagnostic algorithm. Spondylolysis magnetic resonance imaging computed tomography Figures Figure 1 Figure 2 INTRODUCTION Spondylolysis is defined as a unilateral or bilateral bony defect in the pars interarticularis of the vertebra. Anatomically, the pars interarticularis represents the junction point of the pedicle, articular facets, and lamina [ 1 ]. With an estimated prevalence ranging from 3% to 6% in the general population, spondylolysis is recognized as a leading cause of low back pain among pediatric and adolescent athletes [ 2 ]. Although the majority of cases remain asymptomatic, defects in the pars interarticularis can progressively lead to spondylolisthesis, eventually causing radicular symptoms and severe functional impairment [ 3 ]. While there is no universally established single imaging gold standard for the diagnosis of spondylolysis, the diagnostic approach should aim to maximize clinical yield while minimizing radiation exposure, carefully weighing the risks and benefits of plain radiography, computed tomography (CT), single-photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI) [ 4 ]. Radiographic diagnosis is frequently achieved using lateral and oblique spinal radiographs or CT. Nuclear medicine modalities, particularly SPECT scans, can be utilized to differentiate between acute and chronic spondylolytic lesions [ 5 ]. MRI is frequently requested by clinicians for the evaluation of individuals with low back pain and has largely replaced plain radiographs as the "first-line" imaging modality in many settings [ 6 ]. However, literature indicates that up to 30% of spondylolysis cases diagnosed via CT may be missed on MRI [ 7 ]. Conversely, although CT is regarded as the "gold standard" for imaging the bony anatomy of the neural arch and demonstrating the presence of complete or incomplete lysis, MRI exhibits higher sensitivity in detecting early-stage stress or overload-induced alterations at the pars level [ 8 ]. Therefore, a comparative evaluation of the recognizability of spondylolysis on MRI and CT in patients with chronic low back pain is of clinical significance to determine the diagnostic adequacy of MRI and to establish the most appropriate imaging paradigm [ 9 ]. MATERIALS AND METHODS Study Design and Ethical Approval : This single-center, retrospective cohort analysis reviewed the medical records and radiological images of patients who presented to the Physical Medicine and Rehabilitation outpatient clinic of Karabuk Training and Research Hospital with complaints of chronic low back pain between December 2024 and December 2025. The study protocol was approved by the Non-Interventional Clinical Research Ethics Committee of Karabuk University Faculty of Medicine (Approval No: 2568), with all procedures complying with the Declaration of Helsinki guidelines. The primary inclusion criterion was the availability of concurrent (or closely dated) lumbar Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans in the hospital's database. Data Collection and Evaluation Parameters: Out of the 2,104 patients screened during the study period, 67 (3.1%) with a radiologically confirmed diagnosis of lumbar spondylolysis were included in the study cohort. Patient data were retrieved via the hospital information system and the Picture Archiving and Communication System (PACS). All MRI examinations included in the study were performed using a 1.5-Tesla scanner utilizing standard lumbar spine protocols (T1-weighted, T2-weighted, STIR, and fat-suppressed sequences). The retrospective analysis of the radiological images was conducted by a single specialist radiologist with 10 years of experience in musculoskeletal imaging. To minimize diagnostic bias, a stepwise evaluation protocol was employed. In the initial phase, the radiologist evaluated the MRI scans of the 2,104 patients while blinded to the CT results, specifically noting any signal alterations at the pars interarticularis . In the subsequent phase, the CT images of all patients were reviewed to establish the definitive diagnosis and determine the anatomical level of spondylolysis. For each patient, demographic characteristics (age, gender) and the following radiological parameters were documented: Level and Laterality: The vertebral level of the defect and its localization (unilateral or bilateral). Classification of MRI Findings: MRI signs indicative of spondylolysis were categorized into three groups: No Findings: Absence of pathological signal changes in the pars interarticularis. Suspicious Findings: Signal alterations consistent with bone marrow edema and stress reaction at the corresponding level. Definitive Findings: Clear visualization of a fracture line at the affected pars interarticularis. Degenerative Changes: The presence of lumbar degeneration was dichotomously classified as 'present' or 'absent' based on findings such as vertebral body irregularities, osteophyte formation, and narrowing of the intervertebral disc space. Pars interarticularis lesions observed on MRI were graded according to the classification system proposed by Hollenberg et al. [10], which is based on the presence of bone marrow edema and fracture lines. The staging was defined as follows: Stage 0 (Normal): Normal pars interarticularis with no signal alterations on MRI. Stage 1 (Stress Reaction): Presence of bone marrow edema with intact cortical integrity. Stage 2 (Incomplete Stress Fracture): Bone marrow edema accompanied by an incomplete cortical fracture or fissure. Stage 3 (Acute Complete Fracture): Full-thickness cortical fracture extending across the pars interarticularis, associated with bone marrow edema. Stage 4 (Chronic Fracture): Full-thickness fracture line across the pars interarticularis without accompanying bone marrow edema (no signal change). For the purposes of statistical analysis and clinical correlation, these stages were collapsed into three main categories: Stage 0 cases were classified as the "Normal group with no spondylolysis findings," Stage 1 and 2 cases as "Suspicious spondylolysis findings," and Stage 3 and 4 cases as "Definitive spondylolysis findings." During the study period, a retrospective screening was conducted on 2,104 patients who presented to our outpatient clinic with chronic low back pain and met the inclusion criteria (availability of concurrent lumbar CT and MRI scans). Based on the CT imaging, which served as the gold standard, lumbar spondylolysis was identified in 67 out of the 2,104 patients, yielding a prevalence of 3.18%. The cohort of 67 patients diagnosed with spondylolysis consisted of 48 females (71.6%) and 19 males (28.4%). The mean age of the participants was 46.7 ± 11.2 years (range: 20–74 years). Radiological assessments indicated that the vast majority of pars interarticularis defects were bilateral and most frequently affected the L5-S1 level. Single-level involvement was observed in 91.0% (n=61) of the cases, whereas multi-level involvement was present in 9.0% (n=6). Evaluation of vertebral alignment in the affected patients demonstrated that 18 cases (26.9%) had concomitant Grade 1 spondylolisthesis accompanying the pars defect. The remaining 49 patients (73.1%) showed no evidence of listhesis. A detailed summary of the anatomical distribution and demographic characteristics is provided in Table 1. Table 1. Demographic and Radiological Characteristics of the Patients with Spondylolysis Characteristic Count (n=67) Percentage (%) Gender Female 48 71,6 Male 19 28,4 Defect Laterality Bilateral 63 94,0 Unilateral 4 6,0 Level of Involvement Single-Level Involvement 61 91,0 L5-S1 55 82,1 L4-L5 4 6,0 L3-L4 2 3,0 Multi-Level Involvement 6 9,0 L4-L5 and L5-S1 4 6,0 L3-L4 and L5-S1 1 1,5 L3-L4, L4-L5 and L5-S1 1 1,5 Comparison of Imaging Modalities The MRI findings of the 67 patients with a definitive CT-confirmed diagnosis of spondylolysis were further analyzed. Retrospective clinical evaluation of the MRI slices revealed "suspicious findings" indicative of edema and stress reaction in 44.8% (n=30) of the patients, and a "definitive fracture line" in 13.4% (n=9). Notably, in 41.8% of the cases (n=28), no pathological signal alterations were detected in the pars interarticularis region on MRI. However, a review of the routine institutional radiology reports demonstrated a 100% miss rate, as the diagnosis of spondylolysis was overlooked in all MRI reports. Strikingly, 94.0% (n=63) of the corresponding CT reports were also finalized as normal in the routine workflow. A statistically significant association was observed between patient age and the presence of degenerative changes (p < 0.001). The mean age of the group exhibiting degenerative findings (54.0 ± 8.6 years) was significantly higher compared to the cohort without degeneration (40.1 ± 10.5 years) (Table 2). Table 2. Age Distribution According to the Presence of Degeneration Degeneration Status Count (n) Mean Age (Year) Standart Deviation Min - Max p value* Absent 35 40,1 10,5 20 - 64 < 0,001 Present 32 54,0 8,6 40 - 74 Conversely, no statistically significant correlations were found between gender and the presence of degenerative changes (p=0.755), nor between gender and the laterality (unilateral vs. bilateral) of the defect (p=1.000). DISCUSSION The primary objective of this study was to comparatively evaluate the diagnostic reliability of MRI in detecting lumbar spondylolysis against CT, the established gold standard, in patients presenting with chronic low back pain. The most salient finding of our research is that MRI findings were evaluated as completely "normal" in nearly half (41.8%) of the patients who had a definitive pars defect confirmed by CT. Despite the superior soft-tissue resolution of MRI and its high efficacy in detecting bone marrow edema, it was found to be inadequate in visualizing "silent" fracture lines where cortical bone integrity is compromised without an accompanying active stress reaction [11]. Consequently, diagnostic processes relying solely on MRI lead to a high rate of false-negative results and missed diagnoses [12]. Beyond its comparative diagnostic scope, our study also serves as a comprehensive prevalence investigation, screening the imaging modalities of 2,104 patients. Within this extensive cohort of patients presenting with chronic low back pain, the prevalence of CT-confirmed spondylolysis was determined to be 3.18%. This figure is consistent with the 3-6% range reported in the literature for the general population [13]. However, a striking observation in our study was that despite analyzing a symptomatic group, 100% of these cases were overlooked in routine MRI reporting. Had these patients not been retrospectively verified via CT, the actual prevalence of 3.18% would have been erroneously reported as significantly lower. This finding suggests that the true incidence of spondylolysis might be underestimated in MRI-only screening protocols. Recent literature indicating MRI false-negative rates of up to 41% further corroborates the data obtained in the current study [9]. Although pathological signals (edema or fracture lines) were detectable on MRI in 58.2% of the cases during our retrospective evaluation, it is remarkable that the diagnosis was missed entirely (100%) in the routine hospital radiology reports. This phenomenon can be elucidated by the concept of 'Inattentional Blindness' in radiology [14]. When radiologists focus primarily on more prominent pathologies such as disc herniations and spinal canal stenosis in routine practice, minor edema signals or cortical irregularities in a highly specific anatomical region like the pars interarticularis often go unnoticed. The fact that these findings became 'invisible' in the routine workflow, contrary to our CT-guided retrospective scrutiny, underscores the critical importance of clinical suspicion and radiologist awareness. Clinically and radiologically, MRI and CT represent opposite ends of the spondylolysis spectrum. While MRI excels at demonstrating early-stage stress reactions and edema (the pre-spondylolytic phase), it possesses inherent technical limitations in visualizing an established fracture line (the pseudoarthrosis phase), as evidenced by our study [15]. In our cohort, a distinct fracture line—defined as a "definitive finding" on MRI was observed in only 13.4% of the patients. In the vast majority of the group, MRI either yielded only non-specific edema signals or remained completely silent. This technical blindness can be attributed to the fact that the defect in the pars interarticularis occurs within the cortical bone, and MRI is substantially less sensitive than CT in acquiring signals from cortical osseous structures [16]. Another significant finding of our study is the inverse relationship between the presence of degenerative changes and diagnostic success. Contrary to expectations, the rate of missed diagnoses on MRI was notably higher in younger patients without degeneration (51% of patients) compared to the cohort with degenerative changes (31% of patients). While secondary findings such as facet joint hypertrophy or sclerosis might serve as alerting signs for the radiologist in the presence of advanced age and degeneration, the "clean" appearance of the spine in younger patients may facilitate the oversight of an isolated pars defect. This emphasizes that even in the face of a normal MRI—particularly in risk groups with "healthy-looking" spines such as young athletes and adolescents—clinical suspicion must be maintained, and CT imaging must be integrated into the diagnostic process if corresponding clinical history and physical examination findings are present [4]. One of the most striking findings of our study is that 94% of the CT reports, which is considered the gold standard imaging modality for spondylolysis, were reported as normal by the radiologists in the routine clinical workflow. This paradox can be largely attributed to the radiological phenomena known as 'Satisfaction of Search' (SoS) and 'Inattentional Blindness' [14]. In routine practice, radiologists primarily focus on identifying disc herniations, spinal canal stenosis, or gross degenerative changes, which are the most common causes of chronic low back pain. Once a degenerative pathology or disc bulging is identified, the search for secondary or less common bony pathologies, such as a pars interarticularis defect, is often prematurely terminated [15]. Furthermore, the complex anatomical orientation of the pars interarticularis may cause the defect to blend with the adjacent facet joints on routine axial slices, unless specifically reformatted parasagittal or oblique views are actively scrutinized [17]. Our findings strongly suggest that without a specific clinical suspicion or a direct request from the clinician to rule out spondylolysis, radiologists may overlook pars defects, evaluating the images solely through the lens of degenerative disc disease. In conclusion, MRI remains a valuable first-line investigation for ruling out disc and soft-tissue pathologies in patients presenting with chronic low back pain [18]. Nevertheless, our results establish that a normal MRI scan is insufficient to rule out spondylolysis. In patients with a clinical history and physical examination raising suspicion of spondylolysis but possessing a normal MRI report, CT imaging ideally utilizing low-dose protocols to mitigate radiation risk—can be a crucial component of the diagnostic algorithm. Limitations of the Study Certain limitations should be acknowledged when interpreting the results of our study. First, the retrospective and single-center design may restrict the generalizability of our findings to the broader population. Second, the strict inclusion criterion requiring the simultaneous availability of both CT and MRI scans inherently limited the sample size (n=67). A third, technical limitation is that the reviewed MRI images were acquired using standard lumbar spine protocols. Novel "MRI Bone Imaging" sequences, which have recently emerged in the literature promising CT-like visualization of cortical bone, were not utilized in our study. However, this could also be perceived as a strength, as our study reflects "real-world data," given that these specialized sequences are not yet widely implemented in daily clinical practice. CONCLUSION In conclusion, routine lumbar MRI examinations alone are inadequate for diagnosing spondylolysis, a significant etiology in chronic low back pain. Our study demonstrates that standard MRI possesses low sensitivity in detecting defects of the pars interarticularis, and the risk of a missed diagnosis is markedly higher, particularly in younger patients lacking degenerative changes. Although MRI is the preferred initial modality due to radiation concerns, a "normal" MRI report does not guarantee the absence of spondylolysis. Therefore, in cases where clinical suspicion of spondylolysis persists based on physical examination and patient history, yet MRI findings are normal or equivocal, Computed Tomography the gold standard must be incorporated into the diagnostic algorithm utilizing low-dose protocols. Declarations Ethics approval and consent to participate The study was conducted in accordance with the principles of the Declaration of Helsinki. Ethical approval was obtained from the Non-Interventional Clinical Research Ethics Committee of Karabuk University Faculty of Medicine (Approval No: 2568). Due to the retrospective nature of the study, the need for informed consent was waived by the Non-Interventional Clinical Research Ethics Committee of Karabuk University Faculty of Medicine. Consent for publication Not applicable. Availability of data and materials The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding The authors declare that no specific funding was received for this study. Authors' contributions AT conceptualized the study design and methodology. ED performed the radiological evaluation of the imaging modalities and assisted in data collection. All authors read and approved the final manuscript. Acknowledgements Not applicable. Authors' information Not applicable. References Leone, A., et al., Lumbar spondylolysis: a review. Skeletal Radiol, 2011. 40(6): p. 683-700. Soler, T. and C. Calderón, The prevalence of spondylolysis in the Spanish elite athlete. Am J Sports Med, 2000. 28(1): p. 57-62. Kalichman, L., et al., Spondylolysis and spondylolisthesis: prevalence and association with low back pain in the adult community-based population. Spine (Phila Pa 1976), 2009. 34(2): p. 199-205. Tofte, J.N., et al., Imaging pediatric spondylolysis: a systematic review. Spine, 2017. 42(10): p. 777-782. Yamaguchi Jr, K.T., et al., Spondylolysis is frequently missed by MRI in adolescents with back pain. Journal of children's orthopaedics, 2012. 6(3): p. 237-240. Saifuddin, A. and S. Burnett, The value of lumbar spine MRI in the assessment of the pars interarticularis. Clinical radiology, 1997. 52(9): p. 666-671. Ulmer, J.L., et al., MR imaging of lumbar spondylolysis: the importance of ancillary observations. AJR. American journal of roentgenology, 1997. 169(1): p. 233-239. Jiménez, D.E. and B.Á. de Sierra Garcia, Magnetic resonance imaging (MRI) vs. computed tomography (CT) in the diagnosis and classification of spondylolysis and spondylolisthesis—a narrative review. Quantitative Imaging in Medicine and Surgery, 2024. 14(11): p. 7891. West, A.M., et al., Diagnostic Accuracy of Magnetic Resonance Imaging and Computed Tomography Scan in Young Athletes With Spondylolysis. Clin Pediatr (Phila), 2019. 58(6): p. 671-676. Hollenberg, G.M., et al., Stress reactions of the lumbar pars interarticularis: the development of a new MRI classification system. Spine, 2002. 27(2): p. 181-186. Yokoe, T., et al., Predictors of spondylolysis on magnetic resonance imaging in adolescent athletes with low back pain. Orthopaedic Journal of Sports Medicine, 2021. 9(4): p. 2325967121995466. Sairyo, K., et al., MRI signal changes of the pedicle as an indicator for early diagnosis of spondylolysis in children and adolescents: a clinical and biomechanical study. Spine, 2006. 31(2): p. 206-211. Crawford III, C.H., et al., Current evidence regarding the etiology, prevalence, natural history, and prognosis of pediatric lumbar spondylolysis: a report from the scoliosis research society evidence-based medicine committee. Spine deformity, 2015. 3(1): p. 12-29. Alexander, R.G., et al., What do radiologists look for? Advances and limitations of perceptual learning in radiologic search. Journal of Vision, 2020. 20(10): p. 17-17. Viana, S.L., M.A.d.C.B. Viana, and E.L.C. de Alencar, Atypical, unusual, and misleading imaging presentations of spondylolysis. Skeletal radiology, 2015. 44(9): p. 1253-1262. Wehrli, F.W., Structural and functional assessment of trabecular and cortical bone by micro magnetic resonance imaging. Journal of Magnetic Resonance Imaging: An Official Journal of the International Society for Magnetic Resonance in Medicine, 2007. 25(2): p. 390-409. Gagnet, P., et al., Spondylolysis and spondylolisthesis: A review of the literature. J Orthop, 2018. 15(2): p. 404-407. Urban, J.P. and C.P. Winlove, Pathophysiology of the intervertebral disc and the challenges for MRI. Journal of Magnetic Resonance Imaging: An Official Journal of the International Society for Magnetic Resonance in Medicine, 2007. 25(2): p. 419-432. Additional Declarations No competing interests reported. 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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-9247900","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":617851928,"identity":"18f109be-db1d-43bd-b35d-990cb5ec824c","order_by":0,"name":"Ahmet TEZCE","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABCUlEQVRIiWNgGAWjYDACCTiL+TCITGDgAZI8hLQcSACx2JJRtEgQoYXHmDgt/LO7Ex9//GFjz9/e89ng5x67PIMzBxgfvG1jqDNvwGHJnbObDQ4kpDFLnDm7ObHnWXKxwdkGZsO5bQwSMgdwWHMjd5vEgYTDbAYSuZsP8BxgTtxwnoFNmheoBZfL5G/kbv9xIOE/j4H8m8cH/xyoB2lh/41PiwHQFqD3D0gYSPAwJ/McOJy44WwDGzM+LYY3cjdLnElLNgASxsYyB44XS5452Cw555yE5AwcWuRu5G78UGFjBwyxw48l3xyozuM7k3zww5syG37cEYMJGBsY8MXkKBgFo2AUjALCAADrK11P/Vn2iwAAAABJRU5ErkJggg==","orcid":"","institution":"Karabük University","correspondingAuthor":true,"prefix":"","firstName":"Ahmet","middleName":"","lastName":"TEZCE","suffix":""},{"id":617851929,"identity":"ec13aa66-90ef-4e2e-805f-1ac6ec74a7e3","order_by":1,"name":"Emin DURMUŞ","email":"","orcid":"","institution":"Ministry of Health Antalya City Hospital","correspondingAuthor":false,"prefix":"","firstName":"Emin","middleName":"","lastName":"DURMUŞ","suffix":""}],"badges":[],"createdAt":"2026-03-27 19:38:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9247900/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9247900/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106543521,"identity":"e5d41dd5-ac60-4a8d-be16-e6eb48db4d08","added_by":"auto","created_at":"2026-04-09 16:37:46","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":269951,"visible":true,"origin":"","legend":"\u003cp\u003eRadiological imaging of Patient 1. \u003cstrong\u003e(A)\u003c/strong\u003eCT scan demonstrating a fracture line at the pars interarticularis of the L5-S1 level. \u003cstrong\u003e(B)\u003c/strong\u003e MRI scan showing suspicious findings at the L5-S1 level, characterized by mild bone marrow edema with preserved cortical integrity.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-9247900/v1/fa8bf81f1b5d7fa410443ee4.png"},{"id":106543522,"identity":"2138a391-ae95-445b-bff0-ff8ef245fbd4","added_by":"auto","created_at":"2026-04-09 16:37:46","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":411233,"visible":true,"origin":"","legend":"\u003cp\u003eRadiological imaging of Patient 2. \u003cstrong\u003e(A)\u003c/strong\u003eCT scan demonstrating a fracture line at the pars interarticularis of the L5-S1 level. \u003cstrong\u003e(B)\u003c/strong\u003e MRI scan displaying definitive findings at the L5-S1 pars interarticularis, with a visible fracture line and loss of cortical integrity.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-9247900/v1/7ef09d168f86925dcf5181a6.png"},{"id":106724922,"identity":"bc33d7db-2137-40f4-bfb4-a0f0a69f7931","added_by":"auto","created_at":"2026-04-12 18:30:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1797711,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9247900/v1/8ec5969d-d4d3-4d10-ace4-9ce5524d47c0.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Diagnostic Accuracy of Magnetic Resonance Imaging versus Computed Tomography for Lumbar Spondylolysis in Patients with Chronic Low Back Pain: A Single-Center Retrospective Study","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eSpondylolysis is defined as a unilateral or bilateral bony defect in the pars interarticularis of the vertebra. Anatomically, the pars interarticularis represents the junction point of the pedicle, articular facets, and lamina [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWith an estimated prevalence ranging from 3% to 6% in the general population, spondylolysis is recognized as a leading cause of low back pain among pediatric and adolescent athletes [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Although the majority of cases remain asymptomatic, defects in the pars interarticularis can progressively lead to spondylolisthesis, eventually causing radicular symptoms and severe functional impairment [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWhile there is no universally established single imaging gold standard for the diagnosis of spondylolysis, the diagnostic approach should aim to maximize clinical yield while minimizing radiation exposure, carefully weighing the risks and benefits of plain radiography, computed tomography (CT), single-photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI) [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Radiographic diagnosis is frequently achieved using lateral and oblique spinal radiographs or CT. Nuclear medicine modalities, particularly SPECT scans, can be utilized to differentiate between acute and chronic spondylolytic lesions [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMRI is frequently requested by clinicians for the evaluation of individuals with low back pain and has largely replaced plain radiographs as the \"first-line\" imaging modality in many settings [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. However, literature indicates that up to 30% of spondylolysis cases diagnosed via CT may be missed on MRI [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Conversely, although CT is regarded as the \"gold standard\" for imaging the bony anatomy of the neural arch and demonstrating the presence of complete or incomplete lysis, MRI exhibits higher sensitivity in detecting early-stage stress or overload-induced alterations at the pars level [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTherefore, a comparative evaluation of the recognizability of spondylolysis on MRI and CT in patients with chronic low back pain is of clinical significance to determine the diagnostic adequacy of MRI and to establish the most appropriate imaging paradigm [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cp\u003e\u003cstrong\u003eStudy Design and Ethical Approval\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eThis single-center, retrospective cohort analysis reviewed the medical records and radiological images of patients who presented to the Physical Medicine and Rehabilitation outpatient clinic of Karabuk Training and Research Hospital with complaints of chronic low back pain between December 2024 and December 2025. The study protocol was approved by the Non-Interventional Clinical Research Ethics Committee of Karabuk University Faculty of Medicine (Approval No: 2568), with all procedures complying with the Declaration of Helsinki guidelines. The primary inclusion criterion was the availability of concurrent (or closely dated) lumbar Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans in the hospital\u0026apos;s database.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Collection and Evaluation Parameters:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e Out of the 2,104 patients screened during the study period, 67 (3.1%) with a radiologically confirmed diagnosis of lumbar spondylolysis were included in the study cohort. Patient data were retrieved via the hospital information system and the Picture Archiving and Communication System (PACS).\u003c/p\u003e\n\u003cp\u003eAll MRI examinations included in the study were performed using a 1.5-Tesla scanner utilizing standard lumbar spine protocols (T1-weighted, T2-weighted, STIR, and fat-suppressed sequences).\u003c/p\u003e\n\u003cp\u003eThe retrospective analysis of the radiological images was conducted by a single specialist radiologist with 10 years of experience in musculoskeletal imaging. To minimize diagnostic bias, a stepwise evaluation protocol was employed. In the initial phase, the radiologist evaluated the MRI scans of the 2,104 patients while blinded to the CT results, specifically noting any signal alterations at the pars interarticularis . In the subsequent phase, the CT images of all patients were reviewed to establish the definitive diagnosis and determine the anatomical level of spondylolysis.\u003c/p\u003e\n\u003cp\u003eFor each patient, demographic characteristics (age, gender) and the following radiological parameters were documented:\u003c/p\u003e\n\u003col start=\"1\" type=\"1\"\u003e\n \u003cli\u003e\u003cstrong\u003eLevel and Laterality:\u003c/strong\u003e The vertebral level of the defect and its localization (unilateral or bilateral).\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eClassification of MRI Findings:\u003c/strong\u003e MRI signs indicative of spondylolysis were categorized into three groups:\u003cul type=\"circle\"\u003e\n \u003cli\u003e\u003cstrong\u003eNo Findings:\u003c/strong\u003e Absence of pathological signal changes in the pars interarticularis.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eSuspicious Findings:\u003c/strong\u003e Signal alterations consistent with bone marrow edema and stress reaction at the corresponding level.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eDefinitive Findings:\u003c/strong\u003e Clear visualization of a fracture line at the affected pars interarticularis.\u003c/li\u003e\n \u003c/ul\u003e\n \u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eDegenerative Changes:\u003c/strong\u003e The presence of lumbar degeneration was dichotomously classified as \u0026apos;present\u0026apos; or \u0026apos;absent\u0026apos; based on findings such as vertebral body irregularities, osteophyte formation, and narrowing of the intervertebral disc space.\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003ePars interarticularis lesions observed on MRI were graded according to the classification system proposed by Hollenberg et al. [10], which is based on the presence of bone marrow edema and fracture lines. The staging was defined as follows:\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eStage 0 (Normal):\u003c/strong\u003e Normal pars interarticularis with no signal alterations on MRI.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eStage 1 (Stress Reaction):\u003c/strong\u003e Presence of bone marrow edema with intact cortical integrity.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eStage 2 (Incomplete Stress Fracture):\u003c/strong\u003e Bone marrow edema accompanied by an incomplete cortical fracture or fissure.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eStage 3 (Acute Complete Fracture):\u003c/strong\u003e Full-thickness cortical fracture extending across the pars interarticularis, associated with bone marrow edema.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eStage 4 (Chronic Fracture):\u003c/strong\u003e Full-thickness fracture line across the pars interarticularis without accompanying bone marrow edema (no signal change).\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eFor the purposes of statistical analysis and clinical correlation, these stages were collapsed into three main categories: Stage 0 cases were classified as the \u0026quot;Normal group with no spondylolysis findings,\u0026quot; Stage 1 and 2 cases as \u0026quot;Suspicious spondylolysis findings,\u0026quot; and Stage 3 and 4 cases as \u0026quot;Definitive spondylolysis findings.\u0026quot;\u003c/p\u003e\n\u003cp\u003eDuring the study period, a retrospective screening was conducted on 2,104 patients who presented to our outpatient clinic with chronic low back pain and met the inclusion criteria (availability of concurrent lumbar CT and MRI scans). Based on the CT imaging, which served as the gold standard, lumbar spondylolysis was identified in 67 out of the 2,104 patients, yielding a prevalence of 3.18%.\u003c/p\u003e\n\u003cp\u003eThe cohort of 67 patients diagnosed with spondylolysis consisted of 48 females (71.6%) and 19 males (28.4%). The mean age of the participants was 46.7 \u0026plusmn; 11.2 years (range: 20\u0026ndash;74 years).\u003c/p\u003e\n\u003cp\u003eRadiological assessments indicated that the vast majority of pars interarticularis defects were bilateral and most frequently affected the L5-S1 level. Single-level involvement was observed in 91.0% (n=61) of the cases, whereas multi-level involvement was present in 9.0% (n=6).\u003c/p\u003e\n\u003cp\u003eEvaluation of vertebral alignment in the affected patients demonstrated that 18 cases (26.9%) had concomitant Grade 1 spondylolisthesis accompanying the pars defect. The remaining 49 patients (73.1%) showed no evidence of listhesis. A detailed summary of the anatomical distribution and demographic characteristics is provided in Table 1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1. Demographic and Radiological Characteristics of the Patients with Spondylolysis\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"505\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCharacteristic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCount (n=67)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePercentage (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eGender\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e71,6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e28,4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eDefect Laterality\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBilateral\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e94,0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eUnilateral\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6,0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eLevel of Involvement\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eSingle-Level Involvement\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e61\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e91,0\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eL5-S1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e82,1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eL4-L5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6,0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eL3-L4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3,0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMulti-Level Involvement\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e9,0\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eL4-L5 and L5-S1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6,0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eL3-L4 and L5-S1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1,5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eL3-L4, L4-L5 and L5-S1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1,5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eComparison of Imaging Modalities\u003c/strong\u003e The MRI findings of the 67 patients with a definitive CT-confirmed diagnosis of spondylolysis were further analyzed. Retrospective clinical evaluation of the MRI slices revealed \u0026quot;suspicious findings\u0026quot; indicative of edema and stress reaction in 44.8% (n=30) of the patients, and a \u0026quot;definitive fracture line\u0026quot; in 13.4% (n=9). Notably, in 41.8% of the cases (n=28), no pathological signal alterations were detected in the pars interarticularis region on MRI.\u003c/p\u003e\n\u003cp\u003eHowever, a review of the routine institutional radiology reports demonstrated a 100% miss rate, as the diagnosis of spondylolysis was overlooked in all MRI reports. Strikingly, 94.0% (n=63) of the corresponding CT reports were also finalized as normal in the routine workflow.\u003c/p\u003e\n\u003cp\u003eA statistically significant association was observed between patient age and the presence of degenerative changes (p \u0026lt; 0.001). The mean age of the group exhibiting degenerative findings (54.0 \u0026plusmn; 8.6 years) was significantly higher compared to the cohort without degeneration (40.1 \u0026plusmn; 10.5 years) (Table 2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2. Age Distribution According to the Presence of Degeneration\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eDegeneration Status\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCount (n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean Age (Year)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eStandart Deviation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMin - Max\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep value*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAbsent\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e40,1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e20 - 64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt; 0,001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePresent\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e54,0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e40 - 74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eConversely, no statistically significant correlations were found between gender and the presence of degenerative changes (p=0.755), nor between gender and the laterality (unilateral vs. bilateral) of the defect (p=1.000).\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThe primary objective of this study was to comparatively evaluate the diagnostic reliability of MRI in detecting lumbar spondylolysis against CT, the established gold standard, in patients presenting with chronic low back pain. The most salient finding of our research is that MRI findings were evaluated as completely \u0026quot;normal\u0026quot; in nearly half (41.8%) of the patients who had a definitive pars defect confirmed by CT. Despite the superior soft-tissue resolution of MRI and its high efficacy in detecting bone marrow edema, it was found to be inadequate in visualizing \u0026quot;silent\u0026quot; fracture lines where cortical bone integrity is compromised without an accompanying active stress reaction [11]. Consequently, diagnostic processes relying solely on MRI lead to a high rate of false-negative results and missed diagnoses [12].\u003c/p\u003e\n\u003cp\u003eBeyond its comparative diagnostic scope, our study also serves as a comprehensive prevalence investigation, screening the imaging modalities of 2,104 patients. Within this extensive cohort of patients presenting with chronic low back pain, the prevalence of CT-confirmed spondylolysis was determined to be 3.18%. This figure is consistent with the 3-6% range reported in the literature for the general population [13]. However, a striking observation in our study was that despite analyzing a symptomatic group, 100% of these cases were overlooked in routine MRI reporting. Had these patients not been retrospectively verified via CT, the actual prevalence of 3.18% would have been erroneously reported as significantly lower. This finding suggests that the true incidence of spondylolysis might be underestimated in MRI-only screening protocols. Recent literature indicating MRI false-negative rates of up to 41% further corroborates the data obtained in the current study [9].\u003c/p\u003e\n\u003cp\u003eAlthough pathological signals (edema or fracture lines) were detectable on MRI in 58.2% of the cases during our retrospective evaluation, it is remarkable that the diagnosis was missed entirely (100%) in the routine hospital radiology reports. This phenomenon can be elucidated by the concept of \u0026apos;Inattentional Blindness\u0026apos; in radiology [14]. When radiologists focus primarily on more prominent pathologies such as disc herniations and spinal canal stenosis in routine practice, minor edema signals or cortical irregularities in a highly specific anatomical region like the pars interarticularis often go unnoticed. The fact that these findings became \u0026apos;invisible\u0026apos; in the routine workflow, contrary to our CT-guided retrospective scrutiny, underscores the critical importance of clinical suspicion and radiologist awareness.\u003c/p\u003e\n\u003cp\u003eClinically and radiologically, MRI and CT represent opposite ends of the spondylolysis spectrum. While MRI excels at demonstrating early-stage stress reactions and edema (the pre-spondylolytic phase), it possesses inherent technical limitations in visualizing an established fracture line (the pseudoarthrosis phase), as evidenced by our study [15]. In our cohort, a distinct fracture line\u0026mdash;defined as a \u0026quot;definitive finding\u0026quot; on MRI was observed in only 13.4% of the patients. In the vast majority of the group, MRI either yielded only non-specific edema signals or remained completely silent. This technical blindness can be attributed to the fact that the defect in the pars interarticularis occurs within the cortical bone, and MRI is substantially less sensitive than CT in acquiring signals from cortical osseous structures [16].\u003c/p\u003e\n\u003cp\u003eAnother significant finding of our study is the inverse relationship between the presence of degenerative changes and diagnostic success. Contrary to expectations, the rate of missed diagnoses on MRI was notably higher in younger patients without degeneration (51% of patients) compared to the cohort with degenerative changes (31% of patients). While secondary findings such as facet joint hypertrophy or sclerosis might serve as alerting signs for the radiologist in the presence of advanced age and degeneration, the \u0026quot;clean\u0026quot; appearance of the spine in younger patients may facilitate the oversight of an isolated pars defect. This emphasizes that even in the face of a normal MRI\u0026mdash;particularly in risk groups with \u0026quot;healthy-looking\u0026quot; spines such as young athletes and adolescents\u0026mdash;clinical suspicion must be maintained, and CT imaging must be integrated into the diagnostic process if corresponding clinical history and physical examination findings are present [4].\u003c/p\u003e\n\u003cp\u003eOne of the most striking findings of our study is that 94% of the CT reports, which is considered the gold standard imaging modality for spondylolysis, were reported as normal by the radiologists in the routine clinical workflow. This paradox can be largely attributed to the radiological phenomena known as \u0026apos;Satisfaction of Search\u0026apos; (SoS) and \u0026apos;Inattentional Blindness\u0026apos; [14]. In routine practice, radiologists primarily focus on identifying disc herniations, spinal canal stenosis, or gross degenerative changes, which are the most common causes of chronic low back pain. Once a degenerative pathology or disc bulging is identified, the search for secondary or less common bony pathologies, such as a pars interarticularis defect, is often prematurely terminated [15]. Furthermore, the complex anatomical orientation of the pars interarticularis may cause the defect to blend with the adjacent facet joints on routine axial slices, unless specifically reformatted parasagittal or oblique views are actively scrutinized [17]. Our findings strongly suggest that without a specific clinical suspicion or a direct request from the clinician to rule out spondylolysis, radiologists may overlook pars defects, evaluating the images solely through the lens of degenerative disc disease.\u003c/p\u003e\n\u003cp\u003eIn conclusion, MRI remains a valuable first-line investigation for ruling out disc and soft-tissue pathologies in patients presenting with chronic low back pain [18]. Nevertheless, our results establish that a normal MRI scan is insufficient to rule out spondylolysis. In patients with a clinical history and physical examination raising suspicion of spondylolysis but possessing a normal MRI report, CT imaging ideally utilizing low-dose protocols to mitigate radiation risk\u0026mdash;can be a crucial component of the diagnostic algorithm.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLimitations of the Study\u003c/strong\u003e Certain limitations should be acknowledged when interpreting the results of our study. First, the retrospective and single-center design may restrict the generalizability of our findings to the broader population. Second, the strict inclusion criterion requiring the simultaneous availability of both CT and MRI scans inherently limited the sample size (n=67). A third, technical limitation is that the reviewed MRI images were acquired using standard lumbar spine protocols. Novel \u0026quot;MRI Bone Imaging\u0026quot; sequences, which have recently emerged in the literature promising CT-like visualization of cortical bone, were not utilized in our study. However, this could also be perceived as a strength, as our study reflects \u0026quot;real-world data,\u0026quot; given that these specialized sequences are not yet widely implemented in daily clinical practice.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eIn conclusion, routine lumbar MRI examinations alone are inadequate for diagnosing spondylolysis, a significant etiology in chronic low back pain. Our study demonstrates that standard MRI possesses low sensitivity in detecting defects of the pars interarticularis, and the risk of a missed diagnosis is markedly higher, particularly in younger patients lacking degenerative changes. Although MRI is the preferred initial modality due to radiation concerns, a \"normal\" MRI report does not guarantee the absence of spondylolysis. Therefore, in cases where clinical suspicion of spondylolysis persists based on physical examination and patient history, yet MRI findings are normal or equivocal, Computed Tomography the gold standard must be incorporated into the diagnostic algorithm utilizing low-dose protocols.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e The study was conducted in accordance with the principles of the Declaration of Helsinki. Ethical approval was obtained from the Non-Interventional Clinical Research Ethics Committee of Karabuk University Faculty of Medicine (Approval No: 2568). Due to the retrospective nature of the study, the need for informed consent was waived by the Non-Interventional Clinical Research Ethics Committee of Karabuk University Faculty of Medicine.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that no specific funding was received for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAT conceptualized the study design and methodology. ED performed the radiological evaluation of the imaging modalities and assisted in data collection. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLeone, A., et al., Lumbar spondylolysis: a review. Skeletal Radiol, 2011. 40(6): p. 683-700.\u003c/li\u003e\n\u003cli\u003eSoler, T. and C. Calder\u0026oacute;n, The prevalence of spondylolysis in the Spanish elite athlete. Am J Sports Med, 2000. 28(1): p. 57-62.\u003c/li\u003e\n\u003cli\u003eKalichman, L., et al., Spondylolysis and spondylolisthesis: prevalence and association with low back pain in the adult community-based population. Spine (Phila Pa 1976), 2009. 34(2): p. 199-205.\u003c/li\u003e\n\u003cli\u003eTofte, J.N., et al., Imaging pediatric spondylolysis: a systematic review. Spine, 2017. 42(10): p. 777-782.\u003c/li\u003e\n\u003cli\u003eYamaguchi Jr, K.T., et al., Spondylolysis is frequently missed by MRI in adolescents with back pain. Journal of children\u0026apos;s orthopaedics, 2012. 6(3): p. 237-240.\u003c/li\u003e\n\u003cli\u003eSaifuddin, A. and S. Burnett, The value of lumbar spine MRI in the assessment of the pars interarticularis. Clinical radiology, 1997. 52(9): p. 666-671.\u003c/li\u003e\n\u003cli\u003eUlmer, J.L., et al., MR imaging of lumbar spondylolysis: the importance of ancillary observations. AJR. American journal of roentgenology, 1997. 169(1): p. 233-239.\u003c/li\u003e\n\u003cli\u003eJim\u0026eacute;nez, D.E. and B.\u0026Aacute;. de Sierra Garcia, Magnetic resonance imaging (MRI) vs. computed tomography (CT) in the diagnosis and classification of spondylolysis and spondylolisthesis\u0026mdash;a narrative review. Quantitative Imaging in Medicine and Surgery, 2024. 14(11): p. 7891.\u003c/li\u003e\n\u003cli\u003eWest, A.M., et al., Diagnostic Accuracy of Magnetic Resonance Imaging and Computed Tomography Scan in Young Athletes With Spondylolysis. Clin Pediatr (Phila), 2019. 58(6): p. 671-676.\u003c/li\u003e\n\u003cli\u003eHollenberg, G.M., et al., Stress reactions of the lumbar pars interarticularis: the development of a new MRI classification system. Spine, 2002. 27(2): p. 181-186.\u003c/li\u003e\n\u003cli\u003eYokoe, T., et al., Predictors of spondylolysis on magnetic resonance imaging in adolescent athletes with low back pain. Orthopaedic Journal of Sports Medicine, 2021. 9(4): p. 2325967121995466.\u003c/li\u003e\n\u003cli\u003eSairyo, K., et al., MRI signal changes of the pedicle as an indicator for early diagnosis of spondylolysis in children and adolescents: a clinical and biomechanical study. Spine, 2006. 31(2): p. 206-211.\u003c/li\u003e\n\u003cli\u003eCrawford III, C.H., et al., Current evidence regarding the etiology, prevalence, natural history, and prognosis of pediatric lumbar spondylolysis: a report from the scoliosis research society evidence-based medicine committee. Spine deformity, 2015. 3(1): p. 12-29.\u003c/li\u003e\n\u003cli\u003eAlexander, R.G., et al., What do radiologists look for? Advances and limitations of perceptual learning in radiologic search. Journal of Vision, 2020. 20(10): p. 17-17.\u003c/li\u003e\n\u003cli\u003eViana, S.L., M.A.d.C.B. Viana, and E.L.C. de Alencar, Atypical, unusual, and misleading imaging presentations of spondylolysis. Skeletal radiology, 2015. 44(9): p. 1253-1262.\u003c/li\u003e\n\u003cli\u003eWehrli, F.W., Structural and functional assessment of trabecular and cortical bone by micro magnetic resonance imaging. Journal of Magnetic Resonance Imaging: An Official Journal of the International Society for Magnetic Resonance in Medicine, 2007. 25(2): p. 390-409.\u003c/li\u003e\n\u003cli\u003eGagnet, P., et al., Spondylolysis and spondylolisthesis: A review of the literature. J Orthop, 2018. 15(2): p. 404-407.\u003c/li\u003e\n\u003cli\u003eUrban, J.P. and C.P. Winlove, Pathophysiology of the intervertebral disc and the challenges for MRI. Journal of Magnetic Resonance Imaging: An Official Journal of the International Society for Magnetic Resonance in Medicine, 2007. 25(2): p. 419-432.\u003c/li\u003e\n\u003c/ol\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":"Spondylolysis, magnetic resonance imaging, computed tomography","lastPublishedDoi":"10.21203/rs.3.rs-9247900/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9247900/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eThe objective of this study is to compare the diagnostic efficacy of Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) in detecting lumbar spondylolysis among patients presenting with chronic low back pain, and to determine the rate of missed diagnoses when MRI is reported as \"normal\".\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eRadiological images of 2,104 patients who presented with chronic low back pain between December 2024 and December 2025 and underwent simultaneous lumbar CT and MRI were retrospectively reviewed. The study group comprised 67 patients diagnosed with spondylolysis based on CT findings, which served as the gold standard. Demographic characteristics, affected spinal levels, presence of degeneration, and MRI findings (classified as no findings, suspicious findings, or definitive findings) were analyzed.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe prevalence of spondylolysis in the screened population was 3.18%. The mean age of the study cohort was 46.7\u0026thinsp;\u0026plusmn;\u0026thinsp;11.2 years, with a female predominance (71.6%). The most frequently affected level was L5-S1 (82.1%). In the retrospective MRI evaluation of patients with a definitive CT diagnosis, 41.8% exhibited no pathological signal alterations (such as edema or fracture lines) in the pars interarticularis. Furthermore, an analysis of the hospital registry revealed that the diagnosis of spondylolysis was completely missed (100%) in all routine MRI reports. The rate of missed diagnosis on MRI was significantly higher in younger patients without degenerative changes (51%) compared to those with concomitant degeneration (31%).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eRoutine MRI evaluations yield a high rate of false-negative results in the diagnosis of lumbar spondylolysis. A \"normal\" MRI report is insufficient to rule out spondylolysis, particularly in younger patients lacking degenerative changes. In cases where clinical suspicion persists, CT imaging must be incorporated into the diagnostic algorithm.\u003c/p\u003e","manuscriptTitle":"Diagnostic Accuracy of Magnetic Resonance Imaging versus Computed Tomography for Lumbar Spondylolysis in Patients with Chronic Low Back Pain: A Single-Center Retrospective Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-09 16:37:42","doi":"10.21203/rs.3.rs-9247900/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-29T15:37:50+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-26T18:35:57+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"278406897167246584609302287465169040343","date":"2026-04-19T16:18:09+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-13T14:17:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"287047752325949606746400242331628736602","date":"2026-04-09T22:37:27+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"333808626757263330956224864524341735624","date":"2026-04-03T11:49:25+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-03T07:07:07+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-31T12:15:16+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-31T12:15:08+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Musculoskeletal Disorders","date":"2026-03-27T19:23:09+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":"0fb66c72-94b7-4ddd-b331-eaf9c2b5e397","owner":[],"postedDate":"April 9th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Revision requested","date":"2026-04-29T15:37:50+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-10T18:54:17+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-09 16:37:42","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9247900","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9247900","identity":"rs-9247900","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}