Correlation of R2*with fat fraction and bone mineral density and its role in quantitative assessment of osteoporosis

ObjectivesTo investigate the correlation of R2* with vertebral fat fraction (FF) and bone mineral density (BMD), and to explore its role in the quantitative assessment of osteoporosis (OP).MethodsA total of 83 patients with low back pain (59.77 +/- 7.46 years, 30 males) were enrolled, which underwent lumbar MRI in IDEAL-IQ sequences and quantitative computed tomography (QCT) scanning within 48h. The FF, R2*, and BMD of all 415 lumbar vertebrae were respectively measured. According to BMD, all vertebrae were divided into BMD normal, osteopenia, and OP groups, and the difference of FF and R2* among groups was analyzed by one-way ANOVA. The correlation between R2*, FF, and BMD was analyzed by Pearson's test. Taking BMD as the gold standard, the efficacies for FF and R2* in diagnosis of OP and osteopenia were assessed by receiver operating characteristic curve, and their area under the curve (AUC) was compared with DeLong's test.ResultsThe FF and R2* were statistically different among groups (F values of 102.521 and 11.323, both p < 0.05), and R2* were significantly correlated with FF and BMD, respectively (r values of -0.219 and 0.290, both p < 0.05). In diagnosis of OP and osteopenia, the AUCs were 0.776 and 0.778 for FF and 0.638 and 0.560 for R2*, and the AUCs of R2* were lower than those of FF, with Z values of 4.030 and 4.087, both p < 0.001.ConclusionR2* is significantly correlated with FF and BMD and can be used as a complement to FF and BMD for quantitative assessment of OP.

Automated summary

This study investigated the correlation between R2* and vertebral fat fraction (FF) and bone mineral density (BMD), and explored its role in the quantitative assessment of osteoporosis (OP). The results showed that R2* was significantly correlated with FF and BMD. In addition, the area under the curve (AUC) for FF in diagnosing OP was higher than that for R2*. Therefore, R2* can be used as a complement to FF and BMD for the quantitative assessment of OP.