1H-MRS of femoral red and yellow bone marrow fat composition and water content in healthy young men and women at 3 T.

OBJECTIVES: There is a discrepancy between studies suggesting that higher bone marrow fat saturation is associated with impaired health, and studies suggesting that erythropoiesis increases red bone marrow (RBM) fat saturation in young healthy individuals. Here, we seeked to elucidate these discrepancies by using long TE magnetic resonance spectroscopy (MRS) to study both yellow bone marrow (YBM) and RBM in the femur of healthy volunteers. MATERIALS AND METHODS: Thirty-three young healthy volunteers (17 females), age range 20-31 years, underwent long TE 1H MRS at 3.0 T of RBM and YBM fat composition in the left femur. The water content of the bone marrow depots was measured using short TE MRS. RESULTS: The female participants displayed a lower unsaturation in the sampled RBM volume (RBMV) than the males (P < 0.01) without displaying a concomitant difference in YBM (P = 0.42). They also showed a higher water content and broader spectral linewidths in RBM (P = 0.04). The water content in RBM strongly associated with broader spectral linewidths (R = 0.887, P ≪ 0.01) and inversely with RBMV fat unsaturation (R = - 0.365, P = 0.04). DISCUSSION: These results partly support the notion that females display higher rate of erythropoiesis and lower fat unsaturation in RBM.