化学饱和法脂肪抑制MRI肝脏信号衰减的机制及意义

Mechanism and Significance of Decreasing Intensity of Hepatic Signal on Magnetic Resonance Imaging with Fat Saturation Fat-Suppression Sequences

目的 探讨化学饱和法脂肪抑制MRI肝脏信号衰减的机制及意义。方法 家兔、人非脂肪肝与脂肪肝均以化学饱和法脂肪抑制和非脂肪抑制序列扫描 ,测量脂肪抑制前后肝脏的信号强度并计算其衰减率 (SIAR)、肝中脂滴占肝脏单位体积的百分比 (Vv值 )。结果 所有对象脂肪抑制后肝脏信号强度均有明显衰减 ,但轻、中度脂肪肝组和非脂肪肝组的SIAR间无显著性差异 ,SIAR和Vv值相关性不高。结论 化学饱和法脂肪抑制MRI对脂肪组织信号的抑制呈相对非特异性。

Objective To study the mechanism and significance of decreasing intensity of hepatic signal on magnetic resonance imaging with fat saturation and fat suppression. Methods Fat saturation and fat suppression sequences were performed on rabbits and humans.The intensity of hepatic signal and the ratio of hepatic fat content to the liver volume (Vv value) were measured and signal intensity attenuation ratio (SIAR) was calculated. Results Fat suppression images showed a substantial decrease in the intensity of hepatic signal.Comparing with non fat suppression images in all of subjects,there was no significant difference of SIARs between normal livers and the livers with mild and moderate fatty infiltration.Poor linear positive correlation was found between SIAR and Vv value. Conclusion It is relatively nonspecific for fat saturation and fat suppression MR techniques to suppress the signal of hepatic fat.