Abstract: In this paper, we investigate the correlation between bone mineral density (BMD) gotten by lumbar quantitative computed tomography (QCT) with fat fraction (FF), lipid water ratio (LWR) and signal intensity ratio (SIR). Moreover, we assessed the diagnostic value of magnetic resonance spectroscopy (MRS) and in-phase (IP)/opposed-phase (OP) sequence on lumbar osteopenia and osteoporosis. The results of 120 patients who underwent lumbar QCT and MRI examinations due to lumbago and leg pain were analyzed retrospectively. According to the BMD classification criteria of QCT, the patients were divided into three groups including the normal group, osteopenia group and osteoporosis group. MRI examination included MRS and dual-echo IP/OP sequence, and the FF, LWR and IP/OP SIR of 2-4 lumbar vertebras were measured. Pearson correlation analysis was used to evaluate the correlations among FF, LWR, SIR and BMD. One-way analysis of variance was used to compare the differences of FF, LWR, SIR among the three groups. Results showed that the FF, LWR and SIR were negatively correlated with BMD which detected by QCT. FF and LWR were positively correlated with SIR. Significant differences of FF, LWR, SIR and BMD were found among three groups. As a conclusion, MRS and IP/OP sequence indirectly reflect the bone metabolism by detecting bone marrow adipose without invasiveness and radiation.

Key words: MRS, BMD, osteoporosis