Idilman Ilkay S, Keskin Onur, Elhan Atilla Halil, Idilman Ramazan, Karcaaltincaba Musturay
Liver Imaging Team, Hacettepe University, School of Medicine, Department of Radiology, Ankara University, Faculty of Medicine , Ankara , Turkey.
Scand J Gastroenterol. 2014 May;49(5):617-24. doi: 10.3109/00365521.2014.894118. Epub 2014 Apr 2.
To determine the utility of sequential MRI-estimated proton density fat fraction (MRI-PDFF) for quantification of the longitudinal changes in liver fat content in individuals with nonalcoholic fatty liver disease (NAFLD).
A total of 18 consecutive individuals (M/F: 10/8, mean age: 47.7±9.8 years) diagnosed with NAFLD, who underwent sequential PDFF calculations for the quantification of hepatic steatosis at two different time points, were included in the study. All patients underwent T1-independent volumetric multi-echo gradient-echo imaging with T2* correction and spectral fat modeling.
A close correlation for quantification of hepatic steatosis between the initial MRI-PDFF and liver biopsy was observed (rs=0.758, p<0.001). The median interval between two sequential MRI-PDFF measurements was 184 days. From baseline to the end of the follow-up period, serum GGT level and homeostasis model assessment score were significantly improved (p=0.015, p=0.006, respectively), whereas BMI, serum AST, and ALT levels were slightly decreased. MRI-PDFFs were significantly improved (p=0.004). A good correlation between two sequential MRI-PDFF calculations was observed (rs=0.714, p=0.001). With linear regression analyses, only delta serum ALT levels had a significant effect on delta MRI-PDFF calculations (r2=38.6%, p=0.006). At least 5.9% improvement in MRI-PDFF is needed to achieve a normalized abnormal ALT level. The improvement of MRI-PDFF score was associated with the improvement of biochemical parameters in patients who had improvement in delta MRI-PDFF (p<0.05).
MRI-PDFF can be used for the quantification of the longitudinal changes of hepatic steatosis. The changes in serum ALT levels significantly reflected changes in MRI-PDFF in patients with NAFLD.
确定序贯磁共振成像估计的质子密度脂肪分数（MRI-PDFF）在量化非酒精性脂肪性肝病（NAFLD）患者肝脏脂肪含量纵向变化中的效用。
本研究纳入了18例连续诊断为NAFLD的患者（男/女：10/8，平均年龄：47.7±9.8岁），这些患者在两个不同时间点接受了序贯PDFF计算以量化肝脂肪变性。所有患者均接受了T1无关的容积多回波梯度回波成像及T2*校正和频谱脂肪建模。
观察到初始MRI-PDFF与肝活检在肝脂肪变性量化方面具有密切相关性（rs = 0.758，p < 0.001）。两次序贯MRI-PDFF测量之间的中位间隔为184天。从基线到随访期末，血清γ-谷氨酰转移酶（GGT）水平和稳态模型评估得分显著改善（分别为p = 0.015，p = 0.006），而体重指数（BMI）、血清天冬氨酸转氨酶（AST）和丙氨酸转氨酶（ALT）水平略有下降。MRI-PDFF显著改善（p = 0.004）。观察到两次序贯MRI-PDFF计算之间具有良好相关性（rs = 0.714，p = 0.001）。通过线性回归分析，仅血清ALT水平变化对MRI-PDFF计算变化有显著影响（r2 = 38.6%，p = 0.006）。要使异常ALT水平恢复正常，MRI-PDFF至少需要改善5.9%。在MRI-PDFF变化有所改善的患者中，MRI-PDFF评分的改善与生化参数的改善相关（p < 0.05）。
MRI-PDFF可用于量化肝脂肪变性的纵向变化。血清ALT水平变化在NAFLD患者中显著反映了MRI-PDFF的变化。
