Methods: This retrospective study analyzed patients who underwent chest CT and DXA at our hospital between August 2021 and August 2022. Thoracic thoracolumbar segment HU values, lumbar T-scores, and hip T-scores were computed for comparison, and thoracic thoracolumbar segment HU thresholds suggestive of potential bone density abnormalities were established using receiver operating characteristic curves. Results: In total, 470 patients (72.4% women; mean age, 65.5±12.3 years) were included in this study. DXA revealed that of the 470 patients, 90 (19%) had osteoporosis, 180 (38%) had reduced osteopenia, and 200 (43%) had normal bone mineral density (BMD). To differentiate osteoporosis from osteopenia, the HU threshold was established as 105.1 (sensitivity, 54.4%; specificity, 72.2%) for T11 and 85.7 (sensitivity, 69.4%; specificity, 61.1%) for T12. To differentiate between osteopenia and normal BMD, the HU threshold was 146.7 for T11 (sensitivity, 57.5%; specificity, 84.4%) and 135.7 for T12 (sensitivity, 59.5%; specificity, 80%). Conclusions This study supports the significance of HU values from chest CT for BMD assessment. Chest CT provides a new method for clinical opportunistic screening of osteoporosis. When the T11 HU is >146.7 or the T12 HU is >135.7, additional osteoporosis testing is not needed unless a vertebral fracture is detected. If the T11 HU is <105.1 or the T12 HU is <85.7, further DXA testing is strongly advised. In addition, vertebral HU values that fall faster than those of the T11 and L1 vertebrae may explain the high incidence of T12 vertebral fractures.

Objective To investigate the change rule of T1ρ value in the process of lumbar intervertebral disc degeneration(IVDD)based on Pfirrmann grading by Meta-analysis.Methods PubMed,EMBASE,Cochrane Library,CNKI,Wanfang Data,VIP and Sinomed were searched to collect studies on quantitative assessment of IVDD using T1ρ imaging technology.The retrieval time limit was from the establishment of the database to December 20,2022.Meta-analysis was performed using RevMan 5.4 and Stata 14.0 software.Results A total of 12 articles were included,and the numbers of Pfirrmann grade Ⅰ-Ⅴ lumbar discs were 316,1 460,769,430 and 98,respectively.T1ρ relaxation time decreased gradually with the increase of the grade of degeneration.The T1ρ values of grade Ⅰlumbar discs were significantly higher than those of grade Ⅱ lumbar discs[weighted mean difference(WMD)=14.55,95%confidence interval(CI)6.35-22.75,P<0.01],and the T1ρ values of grade Ⅱ lumbar discs were significantly higher than those of grade Ⅲlumbar discs(WMD=34.20,95%CI 27.05-41.34,P<0.01).The T1ρ values of grade Ⅲ lumbar discs were significantly higher than that of grade Ⅳ lumbar discs(WMD=22.94,95%CI 17.08-28.80,P<0.01).The T1ρ values of grade Ⅳ lumbar discs were significantly higher than that of grade Ⅴ lumbar discs(WMD=9.35,95%CI 6.81-11.89,P<0.01).Conclusion T1ρ imaging technology can objectively and quantitatively evaluate degeneration at different stages,especially sensitive to IVDD in the early and middle stages,which can provide imaging evidence for clinical diagnosis of early IVDD.