Vertebral bone attenuation on low-dose chest CT: quantitative volumetric analysis for bone fragility assessment

Abstract

This study evaluated the use of low-dose chest computed tomography (LDCT) for detecting bone fragility. LDCT-measured vertebral bone attenuation by volumetric methods showed good correlation with bone mineral density (BMD) measured by dual-energy x-ray absorptiometry (DXA, and good diagnostic performance for identifying osteoporosis and compression fractures. The results of this study suggest the feasibility of obtaining comprehensive information on bone health in subjects undergoing LDCT.

Introduction: Osteoporosis is a prevalent but underdiagnosed disease that increases fracture risk. This study evaluated the utility of vertebral attenuation derived from low-dose chest computed tomography (LDCT) compared to dual-energy x-ray absorptiometry (DXA) for detecting bone fragility.

Methods: A total of 232 subjects (78 men and 154 women) aged above 50 years who underwent both LDCT and DXA within 30 days were evaluated. LDCT-measured bone attenuation in Hounsfield units (HU) of four vertebrae (T4, T7, T10, and L1) was evaluated using volumetric methods for correlation with DXA-measured bone mineral density (BMD) and for the diagnosis of compression fractures, osteoporosis, and low BMD (osteoporosis or osteopenia) in men and women, with DXA measurements as the reference standard.

Results: The average attenuation of the four vertebrae showed strong correlation with DXA-measured BMD of the lumbar spine (r = 0.726, p < 0.05). In receiver-operating characteristic (ROC) analyses, the area under the curve (AUC) across LDCT-measured thresholds of the average attenuation to distinguish compression fractures was 0.827, and a threshold of 129.5 HU yielded 90.9 % sensitivity and 64.4 % specificity. Similarly, average attenuation showed high AUCs and good diagnostic performance for detecting osteoporosis and low BMD in both men and women. Among 44 subjects with compression fractures, the average bone attenuation showed strong negative correlation with both the worst fracture grade (r = -0.525, p < 0.05) and cumulative fracture grade score (r = -0.633, p < 0.05).

Conclusion: LDCT-measured bone attenuation by volumetric methods showed good correlation with BMD measured by DXA and good diagnostic performance for identifying bone fragility.

Keywords: Bone mineral density; Compression fracture; Low-dose chest CT; Osteoporosis; Volumetric analysis.