肾透明细胞癌多b值DWI的单指数函数与双指数函数分析比较

目的比较肾透明细胞癌(CCRCC)多b值DWI的单、双指数函数分析在术前分级的价值。材料与方法回顾性分析32例透明细胞癌患者的影像学资料及病理资料。根据Fuhrman核分级法分成低、高级别两组。参考常规序列,在肿瘤实质区手动勾画大小约0.30 cm×0.30 cm~0.45 cm×0.45 cm的ROI,记录各b值对应的信号强度值。采用单指数函数计算两组的参数ADC值;应用双指数函数计算两组的F、Dfast和Dslow。比较各参数在两组之间的差异,组间比较采用非参数检验;采用受试者工作特征曲线分析预测高、低级别肾透明细胞癌的效能。当P<0.05,认为有统计学意义。结果低级别组20例,高级别组12例。与低级别的CCRCC相比较,高级别组的ADC值无明显差异(U=50.0,P=0.71),F减低(U=18.0,P=0.01),但是Dfast、Dslow都增大,组间均存在统计学差异(U=15.0,P=0.01;U=20.0,P=0.02)。而且,F,Dfast和Dslow预测高、低级别CCRCC的效能相似(P值分别为0.61、0.77和0.44)。结论与多b值DWI的单指数函数分析相比,双指数函数更适合透明细胞癌术前分级的分析。

The comparison between monoexponential and biexponential function of multi-b DWI in evaluation of clear cell renal cell carcinoma

Objective： To probe the value of monoexponential and biexponential function used in multi-b DWI on the grading of the CCRCC before the surgery.Materials and Methods： The imaging and pathological data sets of 32 cases with CCRCC were assessed retrospectively.There were low grade（Group 1） and high grade（Group 2） group confirmed by Fuhrman Grading.Based on the conventional MR images,the region of interesting was plotted by a radiologist,and ranges from 0.30 cm2to 0.45 cm2in tumorous parenchyma on multi-b DWI.The signal intensity of ROI on DWI each b value were recorded.The ADC value is calculated in monoexponential function,and F,Dfast and Dslow were calculated in biexponential function.The differences of each parameter between two groups were compared with nonparametric test.The receiver operating characteristic curve（ROC） was performed to evaluate diagnosibility during four parameters.There is a significant difference when the P0.05.Results： 20 cases of low grade CCRCC and 12 cases of high grade were confirmed by the pathological test.There is not a significant difference（U=50.0,P=0.71） for ADC between two groups.Compared with Group 1,the F decreased in Group 2（U=18.0,P=0.01）,but Dfast and Dslow increased in Group 2（U=15.0,P=0.01.U=20.0,P=0.02 respectively）.F,Dfast and Dslow have the similar sensitivity and specificity in differential diagnosis between two groups（P=0.61,0.77 and 0.44 respectively）.Conclusions： Compared with the monoexponential function of multi-b DWI,the biexponential function is more suitable for grading of CCRCC preoperatively.