Simultaneous Estimation of the Fat Fraction and R₂* Via T₂*-Corrected 6-Echo Dixon Volumetric Interpolated Breath-hold Examination Imaging for Osteopenia and Osteoporosis Detection: Correlations with Sex, Age, and Menopause

ABSTRACT

OBJECTIVE: To investigate the relationships of T2 *-corrected 6-echo Dixon volumetric interpolated breath-hold examination (VIBE) imaging-based fat fraction (FF) and R2 * values with bone mineral density (BMD); determine their associations with sex, age, and menopause; and evaluate the diagnostic performance of the FF and R2 * for predicting osteopenia and osteoporosis. MATERIALS AND METHODS: This study included 153 subjects who had undergone magnetic resonance (MR) imaging, including MR spectroscopy (MRS) and T2 *-corrected 6-echo Dixon VIBE imaging. The FF and R2 * were measured at the L4 vertebra. The male and female groups were divided into two subgroups according to age or menopause. Lin's concordance and Pearson's correlation coefficients, Bland-Altman 95% limits of agreement, and the area under the curve (AUC) were calculated. RESULTS: The correlation between the spectroscopic and 6-echo Dixon VIBE imaging-based FF values was statistically significant for both readers (pc = 0.940 [reader 1], 0.908 [reader 2]; both p < 0.001). A small measurement bias was observed for the MRS-based FF for both readers (mean difference = −0.3% [reader 1], 0.1% [reader 2]). We found a moderate negative correlation between BMD and the FF (r = −0.411 [reader 1], −0.436 [reader 2]; both p <0.001) with younger men and premenopausal women showing higher correlations. R2 * and BMD were more significantly correlated in women than in men, and the highest correlation was observed in postmenopausal women (r = 0.626 [reader 1], 0.644 [reader 2]; both p < 0.001). For predicting osteopenia and osteoporosis, the FF had a higher AUC in men and R2 * had a higher AUC in women. The AUC for predicting osteoporosis was highest with a combination of the FF and R2 * in postmenopausal women (AUC = 0.872 [reader 1], 0.867 [reader 2]; both p < 0.001). CONCLUSION: The FF and R2 * measured using T2 *-corrected 6-echo Dixon VIBE imaging can serve as predictors of osteopenia and osteoporosis. R2 * might be useful for predicting osteoporosis, especially in postmenopausal women.