基于mDixon方法快速量化非酒精性脂肪肝脂肪含量的研究

Rapid Quantification of Liver Fat Content in Nonalcoholic Fatty Liver Disease Based on m Dixon Method

[目的]利用氢质子磁共振波谱（1H-MRS）作为参考标准,评价mDixon方法在非酒精性脂肪肝（NAFLD）患者量化肝脏脂肪含量的可行性及准确性.[方法]选取70名NAFLD患者在1.5 T磁共振扫描仪行肝脏mDixon容积扫描和1H-MRS采集.1H-MRS扫描采用单体素点分辨波谱分析法,记录亚甲基峰（1.3 ppm）和水峰（4.7 ppm）下面积,计算脂肪分数.mDixon扫描得到的水相及脂相分别传输至Image J图像处理软件进行后处理,测量肝脏脂肪分数.[结果]采用Image J软件在mDixon图像测量得到的肝脏脂肪分数平均为（16.9±8.7）％（范围为6.6％～37.0％）.用1H-MRS测量得到的肝脏脂肪分数平均为（16.0±8.8）％,（范围为5.7％ ～ 41.4％）.Pearson相关系数为0.920（P＜ 0.0001）.用Bland-Ahman方法,95.8％数据点都在95％一致性范围内.[结论]经Image J软件简单处理mDixon方法获得的图像能快速、准确量化NAFLD患者肝脏脂肪含量.

[Objective] To evaluate feasibility and accuracy of liver fat content （LFC） quantified by mDixon method in patients with nonalcoholic fatty liver disease （NAFLD）,with hydrogen （1H） MR spectroscopy as the reference standard.[Methods] A total of 70 patients with NAFLD underwent1.5-T MR imaging with 1H-MR spectroscopy and mDixon volume imaging of liver.Single-voxel point-resolved 1H MR spectroscopy of the liver （Couinaud segment Ⅶ） was performed to calculate the liver fat fraction from the peak areas ofwater （4.7 ppm） and methylene （1.3 ppm）.Water-only（W） and fat-only（F） images created from mDixon sequence were sent to image-post-processing softwareImage J and liver fat fraction were measured in the same position of VOI of 1H MR spectroscopy.[Results] Mean liver fat fraction measured from mDixon sequence by Image J and 1H-MR spectroscopy were （16.9 ± 8.7）％（range,6.6％-37.0％） and （16.0 ± 8.8） ％,（range,5.7％-41.4％）,respectively.Pearson correlation coefficient was 0.920 （P ＜ 0.0001）.With the Bland-Altman method,95.8％ data points were within the 95％ limits of agreement.[Conclusion] mDixon method postprocessed by Image J can be used to rapidly quantify LFC in patients with NAFLD.