Osteoporosis is often accompanied by bone loss with fat accumulation of the red marrow. A novel technique for quantification of iron and fat content by MRI IDEAL-IQ can visualize hematopoietic areas and fatty deposits in bone marrow; however, the relationship between these indices and total hip bone mineral density (BMD) remains unclear. In this study, the proximal femur of 104 men who underwent pelvic MRI and bone densitometry prior to treatment for non-metastatic prostate cancer was retrospectively examined to investigate the R2* value to quantify iron and proton density fat fraction (PDFF) to assess bone marrow fat content. R2* was significantly positively correlated with BMD (r = 0.6017, p < 0.0001), and PDFF was not correlated with BMD (r = -0.1302, p = 0.0512). Patients with BMD T-score ≤ -2.5 had significantly lower R2* than patients with BMD T-score > -2.5; however, there was no significant difference in PDFF. In the ROC analysis, which examined the predictive ability of R2* with BMD T-score ≤ -2.5 as an outcome, the cut-off value of R2* was 50.7 s-1 (AUC 0.817). These results show R2* correlated with BMD. R2* may be a non-invasive surrogate marker for diagnosing male osteoporosis.
Keywords: MRI IDEAL-IQ; Male osteoporosis; prostate cancer.