Correlation Between Bone Density Measured by Routine BMD and Hounsfield Units Assessed on Diagnostic CT-scan: A Cross-sectional Study

Background: previous studies have shown a moderate correlation between bone mineral density (bmd) measured by dual-energy x-ray absorptiometry (dexa) and hounsfield units (hu) assessed on diagnostic computed tomography (ct) scans in the lumbar spine. objectives: in this study, we aimed to evaluate the correlation between dexa scores and hu values for different bones and several anatomical landmarks. methods: in this retrospective study, 214 patients underwent dexa and diagnostic ct scans of different bones, including the proximal humerus (n=96), distal tibia (n=56), distal femur (n=34), and proximal tibia (n=28). hu values of five anatomic landmarks, including the medulla, anteromedial cortex, anterolateral cortex, posteromedial cortex, and posterolateral cortex, were measured, and their correlation with the lowest t-score of the patients was assessed. results: the hu of the center of the medulla was significantly correlated with the lowest t-score in the proximal (r=0.486, p=0.04) and distal tibia (r=0.458, p=0.01). in the proximal humerus, the hu of the anteromedial cortex was significantly correlated with the lowest t-score (r=0.0353, p=0.01). the mean hu of the posterolateral cortex in the proximal humerus was significantly smaller in the osteoporotic patients (p=0.003). the mean hu of the center of the medulla in the proximal tibia was significantly lower in patients with osteoporotic (p=0.036). the mean hu values of the posteromedial cortex and center of the medulla in the distal tibia were significantly larger in patients with normal bmd (p=0.04 both). conclusion: a moderately significant correlation is observed between the lowest t-score and specific anatomical landmarks of the different bones.