直肠磁共振弥散峰度成像可重复性评价

The Reproducibility of Diffusional Kurtosis Imaging for Rectum in Vivo

目的：探讨Philips Achieva 3.0T TX磁共振直肠弥散峰度成像的可重复性。方法：应用Philips Achieva 3.0T TX超导型磁共振扫描仪。8通道体部相控阵线圈。对27例健康志愿者在不同时间（24小时~2周内）行两次行DKI扫描。DKI采用单次激发自旋回波-平面回波（SE-EPI）序列,启用5个扩散梯度场（b=0、500、1000、1500、2000 s/mm2）,扩散梯度同时取X、Y和Z三个方向。由两名5年以上工作经验的医生双盲对图像进行后处理,获得同一层面的MD值、MK值,然后进行统计学分析。结果：所有27例志愿者均成功获得DKI数据。MD值及MK值观察者内相关系数分别为0.962、0.958;变异系数分别为17.8%、18.9%。MD值及MK值观察者间相关系数分别为0.925、0.895;变异系数分别为18.5%、23.6%。结论：直肠弥散峰度成像具有较高的可重复性。

Purpose： To assess the reproducibility of diffusion kurtosis imaging（DKI） for rectum. Methods： This study was approved by our institutional review board and with informed consent. Twenty-seven healthy volunteers underwent 3-T magnetic resonance imaging twice with an interval of 24 hours to 14 days by using axial fat suppressed single-shot echo-planar DK imaging （five b-values） and torso phased-array coil. Parameters maps were obtained for the metric K, a measure of excess kurtosis of diffusion, and corrected diffusion （D）, a corrected diffusion coefficient accounting for the non-Gaussian behavior. The inter- and intra-observer consistency was evaluated by using reliability test in SPSS 11.5. Results： Paired t-tests demonstrated that there was no significant difference between inter- and intra-observer （all P〉0.05）. Intra-class correlation coefficients of the inter- and intra-observer were 0.962 （D）, 0.958 （K） and 0.925 （D）, 0.895 （K） respectively. Coefficients of variation were 17.8% （D）, 18.9% （K） and 18.5% （D）, 23.6% （K）. Conclusion： DKI showed good reproducibility between paired observers and paired scans. The parameters D and K would be the foundation for further experiments and clinical application of DK imaging.