The association between bone density evaluated on CT or MRI versus the gold standard dual-energy X-ray absorptiometry (DEXA) in the lumbar spine and hip: a meta-analysis

Abstract

Introduction CT-based Hounsfield units (HU) and MRI-based vertebral bone quality (VBQ)-scores are opportunistic markers of bone mineral density and potential alternatives for dual-energy X-ray absorptiometry (DEXA). Research question What is the correlation between HU values and VBQ-scores in relation to DEXA, and what is the corresponding area-under-the-curve (AUC)-based diagnostic discrimination to detect osteopenia and osteoporosis? Material and methods PubMed, Embase, Web of Science, Cochrane Library, and CINAHL were searched through August 2025 for studies reporting correlations between DEXA and CT and/or MRI or the AUC-based diagnostic discrimination of CT and/or MRI to detect osteopenia and osteoporosis. Random effects models were used to calculate pooled correlation coefficients and AUC values along with 95% confidence intervals. Results Forty-three studies, including 8222 patients, were analyzed. HU demonstrated stronger correlations with DEXA T-scores than the VBQ-score (maximum correlation coefficient: 0.741 (95% CI: 0.578-0.847) vs. −0.476 (95% CI: −0.548 to −0.398) and greater AUC-based diagnostic discrimination for osteopenia and osteoporosis (maximum AUC: 0.875 (95% CI: 0.841-0.909) vs. 0.806 (95% CI: 0.684-0.929) across all vertebrae and DEXA sites. Correlation and AUC-based diagnostic discrimination of HU were consistent across vertebrae, with slightly better results at L2 and the mean of L1–L4. VBQ-score correlations were highest at L1 and gradually decreased from L1 to L4. Discussion and conclusion When CT is available, HU appears to be the better-supported opportunistic marker for low BMD than VBQ. All vertebrae demonstrated comparable correlation and AUC-based diagnostic discrimination, with L2 HU and the mean of L1-L4 HU showing slightly superior results.