Routine MRI for opportunistic osteoporosis screening: diagnostic accuracy of vertebral bone quality and a novel femoral bone quality score compared with DXA.

Abstract

Objectives: To evaluate vertebral bone quality (VBQ) and femoral bone quality (FBQ) scores as potential imaging markers of bone mineral density (BMD) for opportunistic osteoporosis screening in at‑risk patients and to assess their correlation with DXA T-scores.

Methods: This retrospective cross-sectional study included women ≥ 40 years and men ≥ 50 years who underwent DXA and lumbar spine, hip, or pelvic MRI within 60 days. All MRI examinations were performed at 1.5 T. VBQ and FBQ were obtained using manually placed circular ROIs. FBQ was derived from coronal T1-weighted images using two approaches: femoroacetabular joint fluid (FBQfa) and cerebrospinal fluid (FBQcsf). Interobserver reproducibility was assessed using intraclass correlation coefficient (ICC). Correlations with DXA T-scores and diagnostic performance for osteoporosis were analyzed using Pearson coefficients and ROC curves.

Results: Among 248 patients, VBQ demonstrated excellent reproducibility (ICC = 0.922) and a weak-to-moderate negative correlation with DXA T-scores (r = -0.307; p < 0.001). VBQ values increased across DXA bone density categories, with an optimal cutoff of 3.61 for osteoporosis (AUC = 0.71). FBQcsf showed high reproducibility (ICC = 0.874) compared with FBQfa (ICC = 0.462) but no evidence of correlation with DXA (p = 0.151). FBQcsf distinguished normal BMD from osteopenia (p = 0.002) and, after adjustment for age and sex, also differentiated patients with osteopenia from those with osteoporosis (p = 0.011).

Conclusion: VBQ can serve as an opportunistic exploratory screening marker of low BMD. FBQcsf may complement VBQ by identifying early marrow-related changes, although further validation is required.