Jiongfeng Zhang,1,* Xiaohui Luo,1,* Ruiling Zhou,2,* Chong Guo,1 Kai Xu,1 Gaoyang Qu,1 Le Zou,1 Wenye Yao,1 Shifan Lin,1 Zhiping Zhang1 

1Department of Orthopedics, the 3rd Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, 330008, People’s Republic of China; 2Department of Dermatology, Jiangxi Provincial Dermatology Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, 330008, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Shifan Lin, Email 66031226@qq.com; Zhiping Zhang, Tel +86 791-88862249, Email ndsfy001425@ncu.edu.cn

Objective: To explore the suitable population of CT value for predicting low bone mineral density (low-BMD).
Methods: A total of 1268 patients who underwent chest CT examination and DXA within one-month period retrospectively analyzed. The CT attenuation values of trabecular bone were measured in mid-sagittal plane from thoracic vertebra 7 (T7). Receiver operating characteristic (ROC) curves were used to evaluate the ability to diagnose low-BMD.
Results: The AUC for diagnosing low BMD was larger in women than in men (0.894 vs 0.744, p < 0.05). The AUC increased gradually with the increase of age but decreased gradually with the increase in height and weight (p < 0.05). In females, when specificity was adjusted to approximately 90%, a threshold of 140.25 HU has a sensitivity of 69.3%, which is higher than the sensitivity of 36.5% in males for distinguishing low-BMD from normal. At the age of 70 or more, when specificity was adjusted to approximately 90%, a threshold of 126.31 HU has a sensitivity of 76.1%, which was higher than that of other age groups.
Conclusion: For patients who had completed chest CTs, the CT values were more effective in predicting low-BMD in female, elderly, lower height, and lower weight patients.

Keywords: bone mineral density, chest computed tomography, dual-energy X-ray absorptiometry, attenuation value