CT-Scan as an Opportunistic Osteoporosis Screening Tool in High-Risk Populations; A Diagnostic Study Conducted on a Sample of Urinary Stone Patients

Background: Osteoporosis is a globally common disorder with significant burdens on the quality of life, and therefore, presents the need for a viable screening tool. Objectives: To establish the diagnostic value of opportunistic computed tomography (CT) scan performed routinely on urinary stone patients for identifying and screening osteoporosis, through measuring vertebral trabecular bone attunement in Hounsfield Units. Patients and Methods: Consecutive subjects were enrolled in this cross-sectional study, who suffered from urinary stones and were undergoing percutaneous nephrolithotomy (PCNL) procedure for stone removal at a tertiary referral hospital. The CT imaging data for the patients were retrospectively extracted, and the patients then underwent a dual energy X-ray absorptiometry (DEXA) scan as the standard protocol in measuring bone mineral density (BMD). CTs were assessed, measuring the bone mineral attenuation at the L1 vertebral level. Diagnostic performance protocols and data comparison with DEXA results were measured. Results: Ninety-two patients were enrolled in the study, 31 (34%) of which were designated as osteoporotic according to standard definitions based on DEXA. Vertebral attunement measurements showed sufficient diagnostic performance, with an area under the curve (AUC) of 0.983 (95% confidence interval [CI], 0.961 – 1.000), 93.55% sensitivity (95% CI, 78.55 – 99.21) and 90.16% specificity (95% CI, 79.81 – 96.30) at the pre-designed 160 Hounsfield units (HU) discriminatory threshold. Conclusion: This study showed that in a high-risk population, vertebral trabecular bone attenuation values retrieved from routine CT imaging holds significant diagnostic value when compared to the gold-standard DEXA, and can be utilized as a viable screening method.