A preliminary study of thoracic CT screening combined with quantitative CT for the determination of bone density in the thoracic spine

A preliminary study of thoracic CT screening combined with quantitative CT for the determination of bone density in the thoracic spine | 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 A preliminary study of thoracic CT screening combined with quantitative CT for the determination of bone density in the thoracic spine Dan ZHANG, Shu CUI, Qijun WANG, Huijian FENG, Min MA, Jie ZHANG, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7575231/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objective To explore the diagnostic value of thoracic spine bone density in QCT bone density measurement. Methods The CT imaging data of 149patients whose thoracic CT examinations included the whole thoracic spine and lumbar spine(L1-L3) were retrospectively analysed, and the paired～sample t ～test in SPSS25.0 statistical software was applied to analyse and compare the inter～vertebral bone mineral density; and the distribution characteristics of thoracic spine BMD were compared between different genders using the independent～sample t～test. Results Thoracic spine BMD decreased gradually from cephalad to pedicle. The trend of thoracic spine BMD was decreasing at different ages. Comparison of the mean values of BMD between thoracic spine(T1-T12) and lumbar spine(L1-L3) were statistically significant ( P < 0.05). The comparison of the mean BMD values of different vertebrae combinations with the mean BMD values of lumbar spine(L1-L3) was statistically significant ( P 0.05). Conclusion Thoracic BMD has a pattern of gradual decrease from cephalad to pedicle, which is suggestive for predicting osteoporosis, but it is not feasible to diagnose osteoporosis directly using the diagnostic criteria of lumbar BMD for thoracic BMD. thoracic spine bone mineral density quantitative CT tomography X～ray computed Figures Figure 1 1 Introduction It is well known that osteoporosis (OP) is one of the highly prevalent diseases in middle-aged and elderly people. Among people over 50 years old in China, the prevalence of OP is about 13.53% in men and 28.99% in women [ 1 ]. With the aging of the population, OP has become one of the global public health problems. Bone mineral density (BMD) measurement plays an important role in the diagnosis and treatment of OP [ 2 ]. Regardless of the classical dual energy X-ray absorptiometry (DXA) BMD measurement or the currently used quantitative computed tomography (QCT) BMD measurement method, the location of the region of interest (ROI) is mostly the lumbar spine, followed by the hip. As a result, patients often require a separate X-ray for BMD testing, which increases the dose of X-ray radiation as well as the examination time. The BMD test is even more difficult for patients with disease in the lumbar spine or hip. The thoracic spine is also a favoured region for osteoporotic fractures of the spine, and it has been reported in the literature that the most common site for osteoporotic fractures is the thoracolumbar junction, with the mid-thoracic region of the spine being the second most common site [ 3 – 4 ]. Whether thoracic spine BMD can replace lumbar BMD for the prognosis of OP is an urgent question. At this stage, the application of chest CT physical examination in healthy people is becoming more and more widespread [ 5 – 6 ], and chest CT plain scanning while acquiring thoracic spine BMD means no increase in radiation dose, and also reduces the waiting time of patients for the second examination. Therefore, the present study was to measure thoracolumbar spine BMD in the patients who underwent lumbar spine QCT at the same time as chest CT scanning for lung lesions, in order to explore the change pattern of thoracic spine BMD and the feasibility of replacing lumbar spine BMD with thoracic spine BMD in the diagnosis of OP. 2 Materials and Methods 2.1 Objects of the study The authors collected 149 cases of chest CT screening and lumbar spine QCT from September 2023 to October 2023 at the Physical Examination Centre of the People's Hospital of West Coast New District, Qingdao, China, of which 85 (57.05%) were male and 64 (42.95%) were female, with the age range of 25–79 years old, and the mean age of 50.7 years old. Inclusion criteria: (1) age ≥ 18 years; (2) scanning range including thoracic spine(T1) to lumbar spine(L1) ; (3) thin layer images with 1 mm layer thickness were available in the PACS system for post-processing. Exclusion criteria: (1) patients with traumatic fracture/osteoporotic compression fracture or post-vertebral internal fixation in thoracic spine(T1) to lumbar spine(L3) ; (2) chronic liver and kidney abnormalities, endocrine abnormalities, diabetes mellitus, malignant tumours, and other bone metabolism-affecting disorders; and (3) large bony islands in the spine. The study was approved by the Ethics Committee, and all patients signed an informed consent form. The cases were divided into 3 age groups according to age, namely:18–44 years old group, 45–59 years old group, and ≥ 60 years old group. Age and sex distribution of included casesThere were 46 cases (30.87%) in the 18–44 years group, 24 males and 22 females; 69 cases (46.31%) in the 45–59 years group, 42 males and 27 females; and 34 cases (22.82%) in the ≥ 60 years group, 20 males and 14 females. Table 1 Distribution of vertebral BMD at different age groups (mg/m3) Groups 18ཞ44years 45ཞ59years ≥ 60years T1 254.58 189.50 169.80 T2 245.63 185.04 162.63 T3 200.94 178.86 157.97 T4 190.13 172.83 143.7 T5 187.72 169.16 141.1 T6 180.21 161.46 130.11 T7 170.63 156.24 124.48 T8 168.79 152.2 120.88 T9 177.58 155.19 121.21 T10 180.11 158.94 121.55 T11 173.91 150.75 116.33 T12 170.96 144.33 109.01 Mean lumbar(L1-l3) BMD 171.32 139.57 100.35 Table 2 Distribution of vertebral BMD by gender (mg/m3) Groups Men Women F Value P Value T1 206.95 202.63 0.396 0.857 T2 183.79 218.34 2.401 0.174 T3 182.74 178.48 0.103 0.557 T4 172.00 170.90 0.353 0.876 T5 167.33 170.63 1.25 0.674 T6 159.4 161.22 2.232 0.8 T7 151.79 155.62 3.036 0.551 T8 147.15 154.20 1.893 0.281 T9 149.2 161.19 2.84 0.072 T10 152.83 162.40 1.884 0.156 T11 144.45 157.48 1.631 0.052 T12 139.55 151.06 3.762 0.09 Mean lumbar(L1-l3) BMD 136.36 145.82 5.679 0.178 2.2 Equipment parameters CT examination applied GE 64-row CT scanner, scanning layer thickness 1 mm, screw pitch 1, 120 kV, 150–300 mAs. iCare QCT body model from China was used. Chest CT scanning conditions:Voltage 120 kV, current 125 mA, balloon rotation speed 0.5 s/turn, pitch 1.0, thickness 5 mm, matrix 512×512, scanning range from the lung tip to the level of the lower edge of the lumbar 3 vertebrae. After scanning, the reconstructed images with layer thickness of 1.25 mm, layer spacing of 1.25 mm, and FOV of 400 mm were transferred to the iCare QCT bone densitometry software workstation in China. 2.3 Observational indicators and measurement methods After the images were transferred to the iCare QCT workstation, the thoracic spine data were intercepted in the QCT software (Figs. 1 and 2), and the region of interest (ROI) was delineated on the thoracic spine images, i.e., the upper and lower endplates of the vertebral body were positioned parallel to the horizontal line in the positioning images and the cross-location markers were placed at the (geometric) centre of the vertebral body in each image, and the cancellous bone in the centre of the vertebral body was chosen to be measured, with the edges of the vertebral body being approximately 2–3 mm from the bone cortex and the layer thickness being 9 mm. The layer thickness was 9 mm, and the region of interest (ROI) was set to include as much cancellous bone as possible, avoiding the bone islands and the central vein in the posterior part of the vertebral body (Figs. 3, 4, and 5). The obtained data were automatically entered into the QCT analysis software, and the BMD values of the vertebrae of the subjects (thoracic 1 to lumbar 3) were automatically obtained, and then the average BMD mean values of the combinations of thoracic 1–3, thoracic 4–6, thoracic 7–9, thoracic 10–12, and lumbar 1–3 vertebrae were measured based on one combination of every three vertebrae. All measurements were done independently by 2 mid-level physicians, and the average of both measurements was taken. Consistency was analysed by intraclass correlation coefficient (ICC), and the ICC values were all > 0.9, indicating good inter-observer agreement between the two observers. 2.4 Statistical analysis Statistical analyses were performed using SPSS 25.0 statistical software.ICC test was used to test the consistency of the measurements of the 2 doctors. Measurements that conformed to normal distribution were expressed as mean ± standard deviation (± s). Comparisons between vertebral BMD were made using the paired-samples t test; characteristics of the distribution of thoracic spine BMD values between genders were compared using the independent-samples t test. Differences were defined as statistically significant at P < 0.05. 3 Results The distribution of vertebral BMD in different age groups is shown in Table 2 , and the BMD of the thoracic pine gradually decreased from the cephalic side to the pedicle side. The trend of BMD of thoracic spine in different age groups showed a decreasing trend, see Fig. 6. The distribution of vertebral BMD in different genders is shown in Table 3 . The comparison of the mean values of BMD of thoracic spine(T1-T12) and lumbar spine(L1-L3) was statistically significant in 149 cases ( P < 0.05), see Table 4 . The comparison of the mean values of BMD of different vertebral combinations and lumbar spine(L1-L3) BMD was statistically significant ( P < 0.05) See Table 5. Table 3 Results of paired samples t-test analyses of the mean values of bone mineral density in the 1st to 12th thoracic vertebrae and 1st to 3rd lumbar vertebrae Groups r t P Value T1ཞMean lumbar(L1-l3) BMD 0.253 5.654 0.002 T2ཞMean lumbar(L1-l3) BMD 0.276 4.818 0.001 T3ཞMean lumbar(L1-l3) BMD 0.802 18.232 0 T4ཞMean lumbar(L1-l3) BMD 0.842 15.897 0 T5ཞMean lumbar(L1-l3) BMD 0.87 16.343 0 T6ཞMean lumbar(L1-l3) BMD 0.89 12.386 0 T7ཞMean lumbar(L1-l3) BMD 0.873 7.655 0 T8ཞMean lumbar(L1-l3) BMD 0.893 6.224 0 T9ཞMean lumbar(L1-l3) BMD 0.915 9.898 0 T10ཞMean lumbar(L1-l3) BMD 0.929 12.765 0 T11ཞMean lumbar(L1-l3) BMD 0.934 7.755 0 T12ཞMean lumbar(L1-l3) BMD 0.953 3.844 0 Table 4 Results of paired samples t-test analysis of mean BMD values for different vertebral combinations Groups r t P Value Mean thoracic(T1-T3) BMDཞMean lumbar(L1-l3) BMD 0.481 9.598 0 Mean thoracic(T4-T6) BMDཞMean lumbar(L1-l3) BMD 0.889 16.464 0 Mean thoracic(T7-T9) BMDཞMean lumbar(L1-l3) BMDe 0.912 8.568 0 Mean thoracic(T10-T12) BMDཞMean lumbar(L1-l3) BMD 0.955 9.802 0 Mean thoracic(T1-T3) BMDཞMean thoracic(T4-T6) BMD 0.504 5.05 0 Mean thoracic(T1-T3) BMD ཞMean thoracic(T7-T9) BMD 0.479 7.448 0 Mean thoracic(T1-T3) BMDཞMean thoracic(T10-T12) BMD 0.48 7.829 0 Mean thoracic(T4-T6) BMDཞMean thoracic(T7-T9) BMD 0.934 12.146 0 Mean thoracic(T4-T6) BMDཞMean thoracic(T10-T12) BMD 0.91 11.779 0 Mean thoracic(T7-T9) BMDཞMean thoracic(T10-T12) BMD 0.944 1.994 0.048 4 Discussion At present, with the updating of human health concepts and changes in health patterns, low-dose lung cancer screening has become one of the important examination items in health checkups; at the same time, with the development and application of artificial intelligence software for lung nodules and the widespread development of minimally invasive diagnosis and treatment of lung nodules, lung CT examination is more and more used in clinical practice, and it is more and more important to extend the reuse value of lung CT to achieve multi-disease co-testing, so that the recipients can benefit more from over-medication.QCT is the use of existing CT examination data supplemented by QCT quality control body film and analysis software for BMD examination and body mass composition analysis. Change into more benefit is the current clinicians and imaging physicians should pay more attention to the direction. QCT is the use of existing CT examination data, supplemented by QCT quality control body membrane and analysis software for BMD examination and body composition analysis [ 7 ], such as OP, obesity, fatty liver and other diseases. Its advantage is that it does not increase the cost, examination time and radiation dose of the patient, and it evaluates the patient's BMD while diagnosing clinical diseases [ 8 – 10 ]. The thoracic vertebrae are located in the middle of the spine, and together with the surrounding ribs, they strengthen the stability of the thorax, which makes it difficult to locate the thoracic vertebrae in DXA examination, and DXA examination is a two-dimensional plane measurement, which cannot avoid the sternum and the heart in front of the thoracic vertebrae and other structures, so DXA examination can't be used for thoracic vertebrae BMD measurement.QCT measures volumetric BMD, which can selectively measure the BMD of the vertebral body's cancellous bone, and is not influenced by the surrounding structures, and is a truly meaningful measurement of BMD. structures, which is the most reliable method for volumetric BMD detection in the true sense [ 11 ]. Currently, the lumbar spine or the proximal femur is the location of most BMD tests, and the widely used clinical diagnostic criteria for osteoporosis [ 12 – 14 ] measure the average BMD of the lumbar spine(L1-L2) or lumbar spine(L1-L3), and there are also some studies that have chosen the measurement site of opportunistic osteoporosis screening in the cervical spine [ 15 – 17 ]; the thoracic spine is located between the cervical spine and the lumbar spine, and its structure and function are equivalent to that of the lumbar spine, but the measurement of BMD in the thoracic spine is rarely reported. BMD measurement is rarely reported. Study [ 18 ] showed that QCT for measuring BMD in the thoracic spine has good reproducibility. The data in this study were measured independently by more than two CT imaging physicians, and the measurements of the two physicians were analysed by the intragroup correlation coefficient ICC consistency, and the ICC values were all > 0.9, indicating good inter-observer agreement between the two observers, and also indicating that the measurement of thoracic spine BMD by QCT has a high degree of accuracy and reproducibility. This study also showed that thoracic spine BMD was significantly positively correlated with lumbar spine BMD, and the correlation between thoracic spine BMD and lumbar spine BMD gradually increased from cephalad to pedicle, which is consistent with the literature report [ 19 ], indicating that thoracic spine BMD can respond to the changes in skeletal bone mass and has a predictive effect on OP, so it is feasible to screen for osteoporosis by using the QCT to measure thoracic spine BMD [ 20 ]. The present study showed that the BMD of the thoracic spine in all age groups showed a gradual decrease from the cephalad to the pedicle, and the BMD of the thoracic spine also showed a decreasing trend with age, which is consistent with the findings of many scholars [ 11 , 20 – 22 ]. The anatomical structure of the thoracic spine is different from that of the lumbar spine, the volume of the thoracic spine is smaller than that of the lumbar spine, the thoracic vertebral space is smaller than that of the lumbar vertebral space, and the surrounding area is associated with the ribs, so it is subjected to more stresses than the lumbar spine; the magnitude and direction of the stress are closely related to the growth of the trabeculae [ 19 ], therefore, trabeculae of thoracic spine are more dense than that of the lumbar spine; the intrinsic structure of trabeculae of the skeleton, the mechanical properties and biomechanics of trabeculae are closely related to the BMD [ 23 ]. Therefore, it is hypothesised that this is the reason why the BMD of the thoracic spine is higher than that of the lumbar spine. Moreover, the results of this study showed that the difference between the BMD of thoracic 1–12 vertebrae and the BMD of lumbar 1–3 vertebrae were statistically significant ( P < 0.05), even in the thoracic 12 vertebrae, which is the closest neighbour to the lumbar vertebrae, which is inconsistent with the results of some scholars [ 24 – 25 ], suggesting that the results of thoracic vertebrae BMD measurements can not be used directly to diagnose OP using lumbar vertebrae osteoporosis diagnostic criteria.There are also studies [ 19 , 26 ] showed that thoracic spine BMD would be different between different genders and different ages. The results of this study showed that there was no statistically significant comparison of mean thoracic spine BMD among gender groups, and there was also no statistically significant comparison of mean thoracic spine BMD among different genders in different age groups. To analyse the reasons, there is a certain gap between the male and female ratio in the data of the older age group in this study, which may lead to biased results and needs to be verified with a large sample of data. Shortcomings of this study: the sample size of the study is not large enough, the age grouping of the cases is not balanced, the results may lead to bias; and the sample is selected from the population in the region, the results may have regional characteristics; the sample size should be enlarged in future studies and multi-centre studies should be carried out to improve the accuracy of the results. 5 Conclusion take-home messages QCT detection of thoracic spine BMD is safe and reliable, and thoracic spine BMD has a certain pattern, which is suggestive of predicting OP. Measurement of lumbar spine BMD is currently used in the international consensus for QCT diagnosis of osteoporosis [ 27 ], and it is not feasible to use the diagnostic criteria for lumbar spine BMD directly for thoracic spine BMD. screening for most diseases and lung cancer screening has led to a substantial increase in chest CT examinations, and QCT osteoporosis screening along with diagnosis of clinical disease can enable patients to benefit from this opportunistic strategy. Declarations Author Contribution Zhang Dan – Principal Investigator, study design, experimentation, data collection and collation, manuscript drafting.Cui Shu – Data collection, collation and analysis; paper drafting.Wang Qijun – Data collation and analysis; paper drafting.Feng Huijian – Data collation and analysis; paper drafting.Ma Min – Data collation and analysis; paper drafting.Zhang Jie – Data collation and analysis; paper drafting.Wang Qun – CT scanning and QCT post-processing. Acknowledgement Zhang Dan – Principal Investigator, study design, experimentation, data collection and collation, manuscript drafting.Cui Shu – Data collection, collation and analysis; paper drafting.Wang Qijun – Data collation and analysis; paper drafting.Feng Huijian – Data collation and analysis; paper drafting.Ma Min – Data collation and analysis; paper drafting.Zhang Jie – Data collation and analysis; paper drafting.Wang Qun – CT scanning and QCT post-processing. References Cheng XG, Zhao KP, Zha XJ et al Opportunistic screening using low-dose CT and the prevalence of osteoporosis in China:A nationwide multicenter study. 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Chin J Radiol 2021, 55(4):359–36410.3760/cma.j.cn112149-20200430-00639 Working Group on Chinese Guidelines for the Diagnosis of Osteoporosis by Quantitative CT (2018) Chinese Quantitative CT Osteoporosis Diagnostic Guidelines (2018). Chinese Journal of Health Management, 2019, 13(3): 195–200. 10.3969/j.issn.1006-7108.2019.06.001 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. 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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-7575231","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":521659099,"identity":"f9e1597f-1a7e-4843-acc0-58acef6bd3e9","order_by":0,"name":"Dan 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07:12:00","extension":"html","order_by":27,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":98693,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7575231/v1/dcefdae31069437ae561f68c.html"},{"id":92474468,"identity":"114f4fa5-2727-4699-9ee6-7a422c678dde","added_by":"auto","created_at":"2025-09-30 07:11:59","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":108801,"visible":true,"origin":"","legend":"\u003cp\u003eFigures 1 and 2, Thoracic spine segments intercepted in QCT software. Figures 3, 4, 5, Setting of \"ROI\" for region of interest. Figure 6: Trend of bone mineral density at different ages.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7575231/v1/c503ab3c49ae9e67461dbba0.jpg"},{"id":102076145,"identity":"fa1e6ebc-4ce8-4026-9924-91e8ee0c6efd","added_by":"auto","created_at":"2026-02-06 22:09:20","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":706760,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7575231/v1/384336cf-37fb-40e0-a6d2-4a53d572900e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A preliminary study of thoracic CT screening combined with quantitative CT for the determination of bone density in the thoracic spine","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eIt is well known that osteoporosis (OP) is one of the highly prevalent diseases in middle-aged and elderly people. Among people over 50 years old in China, the prevalence of OP is about 13.53% in men and 28.99% in women [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. With the aging of the population, OP has become one of the global public health problems. Bone mineral density (BMD) measurement plays an important role in the diagnosis and treatment of OP [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Regardless of the classical dual energy X-ray absorptiometry (DXA) BMD measurement or the currently used quantitative computed tomography (QCT) BMD measurement method, the location of the region of interest (ROI) is mostly the lumbar spine, followed by the hip. As a result, patients often require a separate X-ray for BMD testing, which increases the dose of X-ray radiation as well as the examination time. The BMD test is even more difficult for patients with disease in the lumbar spine or hip. The thoracic spine is also a favoured region for osteoporotic fractures of the spine, and it has been reported in the literature that the most common site for osteoporotic fractures is the thoracolumbar junction, with the mid-thoracic region of the spine being the second most common site [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Whether thoracic spine BMD can replace lumbar BMD for the prognosis of OP is an urgent question. At this stage, the application of chest CT physical examination in healthy people is becoming more and more widespread [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], and chest CT plain scanning while acquiring thoracic spine BMD means no increase in radiation dose, and also reduces the waiting time of patients for the second examination. Therefore, the present study was to measure thoracolumbar spine BMD in the patients who underwent lumbar spine QCT at the same time as chest CT scanning for lung lesions, in order to explore the change pattern of thoracic spine BMD and the feasibility of replacing lumbar spine BMD with thoracic spine BMD in the diagnosis of OP.\u003c/p\u003e"},{"header":"2 Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Objects of the study\u003c/h2\u003e\u003cp\u003eThe authors collected 149 cases of chest CT screening and lumbar spine QCT from September 2023 to October 2023 at the Physical Examination Centre of the People's Hospital of West Coast New District, Qingdao, China, of which 85 (57.05%) were male and 64 (42.95%) were female, with the age range of 25\u0026ndash;79 years old, and the mean age of 50.7 years old. Inclusion criteria: (1) age\u0026thinsp;\u0026ge;\u0026thinsp;18 years; (2) scanning range including thoracic spine(T1) to lumbar spine(L1) ; (3) thin layer images with 1 mm layer thickness were available in the PACS system for post-processing. Exclusion criteria: (1) patients with traumatic fracture/osteoporotic compression fracture or post-vertebral internal fixation in thoracic spine(T1) to lumbar spine(L3) ; (2) chronic liver and kidney abnormalities, endocrine abnormalities, diabetes mellitus, malignant tumours, and other bone metabolism-affecting disorders; and (3) large bony islands in the spine. The study was approved by the Ethics Committee, and all patients signed an informed consent form. The cases were divided into 3 age groups according to age, namely:18\u0026ndash;44 years old group, 45\u0026ndash;59 years old group, and \u0026ge;\u0026thinsp;60 years old group. Age and sex distribution of included casesThere were 46 cases (30.87%) in the 18\u0026ndash;44 years group, 24 males and 22 females; 69 cases (46.31%) in the 45\u0026ndash;59 years group, 42 males and 27 females; and 34 cases (22.82%) in the \u0026ge;\u0026thinsp;60 years group, 20 males and 14 females.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDistribution of vertebral BMD at different age groups (mg/m3)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGroups\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e18ཞ44years\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e45ཞ59years\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;60years\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e254.58\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e189.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e169.80\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e245.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e185.04\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e162.63\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e200.94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e178.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e157.97\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e190.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e172.83\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e143.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e187.72\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e169.16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e141.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e180.21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e161.46\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e130.11\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e170.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e156.24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e124.48\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e168.79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e152.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e120.88\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e177.58\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e155.19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e121.21\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e180.11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e158.94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e121.55\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e173.91\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e150.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e116.33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e170.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e144.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e109.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e171.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e139.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e100.35\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\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDistribution of vertebral BMD by gender (mg/m3)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGroups\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMen\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eWomen\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eF\u003c/em\u003e Value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e Value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e206.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e202.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.396\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.857\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e183.79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e218.34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2.401\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.174\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e182.74\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e178.48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.103\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.557\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e172.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e170.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.353\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.876\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e167.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e170.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.674\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e159.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e161.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2.232\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e151.79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e155.62\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3.036\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.551\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e147.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e154.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.893\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.281\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e149.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e161.19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2.84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.072\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e152.83\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e162.40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.884\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.156\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e144.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e157.48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.631\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.052\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e139.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e151.06\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3.762\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.09\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e136.36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e145.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e5.679\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.178\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Equipment parameters\u003c/h2\u003e\u003cp\u003eCT examination applied GE 64-row CT scanner, scanning layer thickness 1 mm, screw pitch 1, 120 kV, 150\u0026ndash;300 mAs. iCare QCT body model from China was used. Chest CT scanning conditions:Voltage 120 kV, current 125 mA, balloon rotation speed 0.5 s/turn, pitch 1.0, thickness 5 mm, matrix 512\u0026times;512, scanning range from the lung tip to the level of the lower edge of the lumbar 3 vertebrae. After scanning, the reconstructed images with layer thickness of 1.25 mm, layer spacing of 1.25 mm, and FOV of 400 mm were transferred to the iCare QCT bone densitometry software workstation in China.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Observational indicators and measurement methods\u003c/h2\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003cp\u003eAfter the images were transferred to the iCare QCT workstation, the thoracic spine data were intercepted in the QCT software (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and 2), and the region of interest (ROI) was delineated on the thoracic spine images, i.e., the upper and lower endplates of the vertebral body were positioned parallel to the horizontal line in the positioning images and the cross-location markers were placed at the (geometric) centre of the vertebral body in each image, and the cancellous bone in the centre of the vertebral body was chosen to be measured, with the edges of the vertebral body being approximately 2\u0026ndash;3 mm from the bone cortex and the layer thickness being 9 mm. The layer thickness was 9 mm, and the region of interest (ROI) was set to include as much cancellous bone as possible, avoiding the bone islands and the central vein in the posterior part of the vertebral body (Figs.\u0026nbsp;3, 4, and 5). The obtained data were automatically entered into the QCT analysis software, and the BMD values of the vertebrae of the subjects (thoracic 1 to lumbar 3) were automatically obtained, and then the average BMD mean values of the combinations of thoracic 1\u0026ndash;3, thoracic 4\u0026ndash;6, thoracic 7\u0026ndash;9, thoracic 10\u0026ndash;12, and lumbar 1\u0026ndash;3 vertebrae were measured based on one combination of every three vertebrae. All measurements were done independently by 2 mid-level physicians, and the average of both measurements was taken. Consistency was analysed by intraclass correlation coefficient (ICC), and the ICC values were all \u0026gt;\u0026thinsp;0.9, indicating good inter-observer agreement between the two observers.\u003c/h2\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Statistical analysis\u003c/h2\u003e\u003cp\u003eStatistical analyses were performed using SPSS 25.0 statistical software.ICC test was used to test the consistency of the measurements of the 2 doctors. Measurements that conformed to normal distribution were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (\u0026plusmn;\u0026thinsp;s). Comparisons between vertebral BMD were made using the paired-samples t test; characteristics of the distribution of thoracic spine BMD values between genders were compared using the independent-samples t test. Differences were defined as statistically significant at \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\u003c/div\u003e"},{"header":"3 Results","content":"\u003cp\u003eThe distribution of vertebral BMD in different age groups is shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, and the BMD of the thoracic pine gradually decreased from the cephalic side to the pedicle side. The trend of BMD of thoracic spine in different age groups showed a decreasing trend, see Fig.\u0026nbsp;6. The distribution of vertebral BMD in different genders is shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The comparison of the mean values of BMD of thoracic spine(T1-T12) and lumbar spine(L1-L3) was statistically significant in 149 cases (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), see Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The comparison of the mean values of BMD of different vertebral combinations and lumbar spine(L1-L3) BMD was statistically significant (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) See Table\u0026nbsp;5.\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\u003eResults of paired samples t-test analyses of the mean values of bone mineral density in the 1st to 12th thoracic vertebrae and 1st to 3rd lumbar vertebrae\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\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=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGroups\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003er\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cem\u003et\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e Value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT1ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.253\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e5.654\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.002\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT2ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.276\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4.818\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT3ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.802\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e18.232\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT4ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.842\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e15.897\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT5ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.87\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e16.343\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT6ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.89\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e12.386\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT7ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.873\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e7.655\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT8ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.893\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e6.224\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT9ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.915\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e9.898\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT10ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.929\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e12.765\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT11ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.934\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e7.755\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT12ཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.953\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3.844\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\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\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\u003eResults of paired samples t-test analysis of mean BMD values for different vertebral combinations\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\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=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGroups\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003er\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cem\u003et\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e Value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean thoracic(T1-T3) BMDཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.481\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e9.598\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean thoracic(T4-T6) BMDཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.889\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e16.464\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean thoracic(T7-T9) BMDཞMean lumbar(L1-l3) BMDe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.912\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e8.568\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean thoracic(T10-T12) BMDཞMean lumbar(L1-l3) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.955\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e9.802\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean thoracic(T1-T3) BMDཞMean thoracic(T4-T6) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.504\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e5.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean thoracic(T1-T3) BMD ཞMean thoracic(T7-T9) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.479\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e7.448\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean thoracic(T1-T3) BMDཞMean thoracic(T10-T12) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e7.829\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean thoracic(T4-T6) BMDཞMean thoracic(T7-T9) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.934\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e12.146\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean thoracic(T4-T6) BMDཞMean thoracic(T10-T12) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.91\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e11.779\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean thoracic(T7-T9) BMDཞMean thoracic(T10-T12) BMD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.944\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.994\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.048\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e"},{"header":"4 Discussion","content":"\u003cp\u003eAt present, with the updating of human health concepts and changes in health patterns, low-dose lung cancer screening has become one of the important examination items in health checkups; at the same time, with the development and application of artificial intelligence software for lung nodules and the widespread development of minimally invasive diagnosis and treatment of lung nodules, lung CT examination is more and more used in clinical practice, and it is more and more important to extend the reuse value of lung CT to achieve multi-disease co-testing, so that the recipients can benefit more from over-medication.QCT is the use of existing CT examination data supplemented by QCT quality control body film and analysis software for BMD examination and body mass composition analysis. Change into more benefit is the current clinicians and imaging physicians should pay more attention to the direction. QCT is the use of existing CT examination data, supplemented by QCT quality control body membrane and analysis software for BMD examination and body composition analysis [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], such as OP, obesity, fatty liver and other diseases. Its advantage is that it does not increase the cost, examination time and radiation dose of the patient, and it evaluates the patient's BMD while diagnosing clinical diseases [\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The thoracic vertebrae are located in the middle of the spine, and together with the surrounding ribs, they strengthen the stability of the thorax, which makes it difficult to locate the thoracic vertebrae in DXA examination, and DXA examination is a two-dimensional plane measurement, which cannot avoid the sternum and the heart in front of the thoracic vertebrae and other structures, so DXA examination can't be used for thoracic vertebrae BMD measurement.QCT measures volumetric BMD, which can selectively measure the BMD of the vertebral body's cancellous bone, and is not influenced by the surrounding structures, and is a truly meaningful measurement of BMD. structures, which is the most reliable method for volumetric BMD detection in the true sense [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Currently, the lumbar spine or the proximal femur is the location of most BMD tests, and the widely used clinical diagnostic criteria for osteoporosis [\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] measure the average BMD of the lumbar spine(L1-L2) or lumbar spine(L1-L3), and there are also some studies that have chosen the measurement site of opportunistic osteoporosis screening in the cervical spine [\u003cspan additionalcitationids=\"CR16\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]; the thoracic spine is located between the cervical spine and the lumbar spine, and its structure and function are equivalent to that of the lumbar spine, but the measurement of BMD in the thoracic spine is rarely reported. BMD measurement is rarely reported. Study [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] showed that QCT for measuring BMD in the thoracic spine has good reproducibility. The data in this study were measured independently by more than two CT imaging physicians, and the measurements of the two physicians were analysed by the intragroup correlation coefficient ICC consistency, and the ICC values were all \u0026gt;\u0026thinsp;0.9, indicating good inter-observer agreement between the two observers, and also indicating that the measurement of thoracic spine BMD by QCT has a high degree of accuracy and reproducibility. This study also showed that thoracic spine BMD was significantly positively correlated with lumbar spine BMD, and the correlation between thoracic spine BMD and lumbar spine BMD gradually increased from cephalad to pedicle, which is consistent with the literature report [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], indicating that thoracic spine BMD can respond to the changes in skeletal bone mass and has a predictive effect on OP, so it is feasible to screen for osteoporosis by using the QCT to measure thoracic spine BMD [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe present study showed that the BMD of the thoracic spine in all age groups showed a gradual decrease from the cephalad to the pedicle, and the BMD of the thoracic spine also showed a decreasing trend with age, which is consistent with the findings of many scholars [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The anatomical structure of the thoracic spine is different from that of the lumbar spine, the volume of the thoracic spine is smaller than that of the lumbar spine, the thoracic vertebral space is smaller than that of the lumbar vertebral space, and the surrounding area is associated with the ribs, so it is subjected to more stresses than the lumbar spine; the magnitude and direction of the stress are closely related to the growth of the trabeculae [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], therefore, trabeculae of thoracic spine are more dense than that of the lumbar spine; the intrinsic structure of trabeculae of the skeleton, the mechanical properties and biomechanics of trabeculae are closely related to the BMD [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Therefore, it is hypothesised that this is the reason why the BMD of the thoracic spine is higher than that of the lumbar spine. Moreover, the results of this study showed that the difference between the BMD of thoracic 1\u0026ndash;12 vertebrae and the BMD of lumbar 1\u0026ndash;3 vertebrae were statistically significant (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), even in the thoracic 12 vertebrae, which is the closest neighbour to the lumbar vertebrae, which is inconsistent with the results of some scholars [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], suggesting that the results of thoracic vertebrae BMD measurements can not be used directly to diagnose OP using lumbar vertebrae osteoporosis diagnostic criteria.There are also studies [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] showed that thoracic spine BMD would be different between different genders and different ages. The results of this study showed that there was no statistically significant comparison of mean thoracic spine BMD among gender groups, and there was also no statistically significant comparison of mean thoracic spine BMD among different genders in different age groups. To analyse the reasons, there is a certain gap between the male and female ratio in the data of the older age group in this study, which may lead to biased results and needs to be verified with a large sample of data.\u003c/p\u003e\u003cp\u003eShortcomings of this study: the sample size of the study is not large enough, the age grouping of the cases is not balanced, the results may lead to bias; and the sample is selected from the population in the region, the results may have regional characteristics; the sample size should be enlarged in future studies and multi-centre studies should be carried out to improve the accuracy of the results.\u003c/p\u003e"},{"header":"5 Conclusion take-home messages","content":"\u003cp\u003eQCT detection of thoracic spine BMD is safe and reliable, and thoracic spine BMD has a certain pattern, which is suggestive of predicting OP.\u003c/p\u003e\u003cp\u003eMeasurement of lumbar spine BMD is currently used in the international consensus for QCT diagnosis of osteoporosis [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], and it is not feasible to use the diagnostic criteria for lumbar spine BMD directly for thoracic spine BMD.\u003c/p\u003e\u003cp\u003escreening for most diseases and lung cancer screening has led to a substantial increase in chest CT examinations, and QCT osteoporosis screening along with diagnosis of clinical disease can enable patients to benefit from this opportunistic strategy.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eZhang Dan \u0026ndash; Principal Investigator, study design, experimentation, data collection and collation, manuscript drafting.Cui Shu \u0026ndash; Data collection, collation and analysis; paper drafting.Wang Qijun \u0026ndash; Data collation and analysis; paper drafting.Feng Huijian \u0026ndash; Data collation and analysis; paper drafting.Ma Min \u0026ndash; Data collation and analysis; paper drafting.Zhang Jie \u0026ndash; Data collation and analysis; paper drafting.Wang Qun \u0026ndash; CT scanning and QCT post-processing.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eZhang Dan \u0026ndash; Principal Investigator, study design, experimentation, data collection and collation, manuscript drafting.Cui Shu \u0026ndash; Data collection, collation and analysis; paper drafting.Wang Qijun \u0026ndash; Data collation and analysis; paper drafting.Feng Huijian \u0026ndash; Data collation and analysis; paper drafting.Ma Min \u0026ndash; Data collation and analysis; paper drafting.Zhang Jie \u0026ndash; Data collation and analysis; paper drafting.Wang Qun \u0026ndash; CT scanning and QCT post-processing.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eCheng XG, Zhao KP, Zha XJ et al Opportunistic screening using low-dose CT and the prevalence of osteoporosis in China:A nationwide multicenter study. 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Chinese Journal of Health Management, 2019, 13(3): 195\u0026ndash;200.\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3969/j.issn.1006-7108.2019.06.001\u003c/span\u003e\u003cspan address=\"10.3969/j.issn.1006-7108.2019.06.001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"thoracic spine, bone mineral density, quantitative CT, tomography, X～ray computed","lastPublishedDoi":"10.21203/rs.3.rs-7575231/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7575231/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective\u003c/strong\u003e To explore the diagnostic value of thoracic spine bone density in QCT bone density measurement.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e The CT imaging data of 149patients whose thoracic CT examinations included the whole thoracic spine and lumbar spine(L1-L3) were retrospectively analysed, and the paired～sample \u003cem\u003et\u003c/em\u003e～test in SPSS25.0 statistical software was applied to analyse and compare the inter～vertebral bone mineral density; and the distribution characteristics of thoracic spine BMD were compared between different genders using the independent～sample t～test.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e Thoracic spine BMD decreased gradually from cephalad to pedicle. The trend of thoracic spine BMD was decreasing at different ages. Comparison of the mean values of BMD between thoracic spine(T1-T12) and lumbar spine(L1-L3) were statistically significant (\u003cem\u003eP\u003c/em\u003e\u0026lt; 0.05). The comparison of the mean BMD values of different vertebrae combinations with the mean BMD values of lumbar spine(L1-L3) was statistically significant (\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.05). Comparison of thoracic vertebral bone density between genders was not statistically significant (p \u0026gt; 0.05).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion \u003c/strong\u003eThoracic BMD has a pattern of gradual decrease from cephalad to pedicle, which is suggestive for predicting osteoporosis, but it is not feasible to diagnose osteoporosis directly using the diagnostic criteria of lumbar BMD for thoracic BMD.\u003c/p\u003e","manuscriptTitle":"A preliminary study of thoracic CT screening combined with quantitative CT for the determination of bone density in the thoracic spine","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-30 07:11:54","doi":"10.21203/rs.3.rs-7575231/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"5584a90a-f327-454b-a832-976ee3661025","owner":[],"postedDate":"September 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-02-06T22:09:00+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-30 07:11:54","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7575231","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7575231","identity":"rs-7575231","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}