梯度回波化学位移MRI诊断非酒精性肝脂肪变性的临床应用

Clinical application of gradient-echo chemical shift MRI in the diagnosis of nonalcoholic fatty Liver disease

目的探讨梯度回波化学位移MRI在诊断非酒精性肝脂肪变性中的临床价值。方法搜集行常规腹部MRI检查+梯度回波同相(in-phase,IP)和反相(out-phase,OP)序列扫描的患者80例,其中临床诊断为脂肪肝患者40例,非脂肪肝患者40例。对比观察二组患者肝脏在常规TSE T1WI、IP和OP像上的信号强度,测量同相位和反相位的信号强度值(SIip和SIop),计算肝脏脂肪变指数(FI,fat index),FI计算公式为:FI=(SIip-SIop)/2SIip。结果 40例脂肪肝患者在常规TSE序列T1WI上肝脏信号未见明显增高,在梯度回波化学位移相上,脂肪肝病灶在OP像上信号强度较IP像有明显下降,脂肪肝组的肝脏脂肪变指数较对照组有显著差异,具有统计学意义。结论梯度回波化学位移MRI对脂肪肝内的脂肪成分相当敏感,能提高对脂肪肝的诊断率,在临床诊断脂肪肝中具有较高的应用价值。

Objective To investigate the clinical value of gradient-echo chemical shift MRI in the diagnosis of nonalcoholic fatty liver disease. Methods 80 patients underwent routine abdominal MRI examination ＋ gradient echo （in-phase, IP） and reverse phase （out-phase, OP） sequence scan. 40 cases were diagnosed as fatty liver by clinical diagnosis, and 40 cases were non fatty liver. The signal intensity of liver in conventional T1WI, IP and OP in the two groups were observed and compared. The signal strength （SIip and SIop） of the in-phase and out-phase was measured, and the calculation formula was FI = （SIip-SIop） / 2SIip. Results In 40 patients with fatty liver, the liver signal was not significantly increased in conventional TSE T1 WI. The signal intensity of all the fatty liver lesions was significantly lower than that of IP in the OP image. There was a significant difference between the fatty liver group and the control group, and the difference was statistically significant. Conclusion Gradient echo chemical shift MRI is very sensitive to fatty liver, can improve the diagnostic rate of fatty liver, and has high application value in clinical diagnosis of fatty fiver.