中文摘要：

目的探讨图像配准技术对正常人体自由呼吸状态下。肾脏MR扩散峰度成像（OKI）图像质量的影响。方法前瞻性收集20名健康志愿者行3个b值（0、500、1000s／mm2）的双肾DKI检查，并对图像进行配准，以DKI模型分别拟合配准前、后的DKI数据，得到配准前、后对应的参数图。由2名医师分别对配准前、后参数图像进行质量评分，并获得各向异性（FA）、平均扩散系数（MD）、轴向扩散系数（D丨丨）、径向扩散系数（D⊥）、平均峰度（MK）、轴向峰度（K丨丨）以及径向峰度（K⊥）值。采用组内相关系数（me）评价2名医师间评价图像质量的一致性，采用符号秩和检验比较配准前、后各参数图质量评分，采用配对样本t检验或符号秩和检验比较配准前、后皮质和髓质各参数图测量值的差异。结果2名医师间测量各参数值的一致性均较好，配准前各参数图像的ICC为0．784～0．821，配准后各参数图像的1CC为0．836～0．934。肾脏DKI配准前、后各参数图质量评分差异均有统计学意义（P均〈0．05）。肾脏皮质、髓质DKI配准前、后各参数值（FA、MD、D丨丨、D⊥、MK、K丨丨和K⊥值）差异均有统计学意义（P均〈0．05）。结论图像配准可获得更高质量的DKI参数图像，并对其参数测量值产生影响。

英文摘要：

Objective To investigate the effect of image registration on quantitative measurements of free breathing diffusion kurtosis imaging （DKI） in normal human kidney. Methods Twenty healthy volunteers were prospectively enrolled to undergo DKI imaging with a 3.0 T MR scanner. Three b values （0, 500, and 1 000 s/mm2） were adopted,with image registration performed after image acquisition. Acquired images were fitted using the DKI fitting model to generate the DKI metric maps,which were performed on both the pre-registration images and post-registration images. Image quality of the derived metric maps （before and after image registration,respectively） was assessed by two radiologists. Measurements of fractional anisotropy （FA）, mean diffusivity （MD）, radial diffusivity （D丨丨）, axial diffusivity （D⊥）, mean kurtosis （MK）, radial kurtosis （K丨丨） and axial kurtosis （K⊥） were conducted. The inter-observer reproducibility of the image quality assessment was analyzed using intra-class correlation coefficient（ICC）. Wilcoxon signed-rank test was used to evaluate the difference in the subjective scores of the metric maps between those obtained before registration and those after registration. While paired t test or Wilcoxon signed-rank test was performed to analyze the difference in the quantitative measurements of DKI metrics of the renal cortex and medulla between those obtained before registration and those after registration.Results For the inter-observer reproducibility, satisfactory ICCs were obtained for the quantitative metric measurements （pre-registration： 0.784 to 0.821 ; post-registration：0.836 to 0.934）. Significant difference was notice between subjective scores for the quality of metric maps （P〈0.05 for each comparison）. In both the renal cortex and medulla, significant difference was noticed between each metric value obtained with pre-registration images and that with post-registration images （P〈0.05 for each comparison）. Conclusion Image reg