磁共振体素内不相干运动扩散加权成像检查对肾透明细胞癌的术前分级诊断效能

Diagnostic value of diffusion-weighted imaging based on intravoxel incoherent motion in preoperative Fuhrman grading of clear-cell renal-cell carcinoma

目的探讨磁共振体素内不相干运动扩散加权成像(IVIM-DWI)检查对肾透明细胞癌(CCRCC)的术前分级诊断效能。方法经手术病理检查证实的CCRCC患者42例,依据Fuhrman核分级法将其分为低级别组(21例)和高级别组(21例)。对两组患者的术前磁共振检查结果进行分析,比较两组表观扩散系数(ADC)、真实扩散系数(D)、灌注相关扩散系数(D*)和灌注分数(f),采用受试者工作特性(ROC)曲线分析上述各参数对CCRCC的分级诊断效能。结果低级别组的ADC、D、D*、f值分别为(1.62±0.24)×10^(-3)mm^2/s、(1.73±0.18)×10^(-3)mm^2/s、(72.18±90.28)×10^(-3)mm^2/s、0.27±0.08,高级别组分别为(1.10±0.58)×10^(-3)mm^2/s、(1.40±0.20)×10^(-3)mm^2/s、(109.46±129.07)×10^(-3)mm^2/s、0.15±0.09;两组的ADC、D、f值相比,P均<0.05;两组的D*值相比,P>0.05。ADC、D、f值鉴别高低级别CCRCC的ROC曲线下面积分别为0.768、0.931、0.830,相应的最佳诊断阈值分别为1.14×10^(-3)mm^2/s、1.59×10^(-3)mm^2/s、0.18。结论术前磁共振IVIM-DWI检查有助于CCRCC的分级诊断,其中D值具有较高的诊断效能。

Objective To investigate the diagnostic value of intravoxel incoherent motion diffusion-weighted imaging （IVIM-DWI）in preoperative Fuhrman grading of clear-cell renal-cell carcinoma （CCRCC）.Methods The imaging and pathological materials of 42 cases with pathologically-confirmed CCRCC were retrospectively assessed.According to Fuhr-man grading,the patients were divided into the low-grade group （n =21）and high-grade group （n =21）.Based on a bi-exponential model,these parameters,including the standard apparent diffusion coefficient （ADC）,the true diffusion coef-ficient （D）,perfusion-related diffusion coefficient （D＊）,and perfusion fraction （f）,were compared between these two groups with nonparametric test （Mann-Whitney U）.And the receiver operating characteristic （ROC）analysis was used to compare the predictive values in preoperatively Fuhrman grading CCRCC among four parameters.Results The average ADC,D,D＊ and f values of the low-grade group were （1.62 ±0.24）×10 ^-3 mm^2 /s,（1.73 ±0.18）×10 ^-3 mm^2 /s, （72.18 ±90.28）×10 ^-3 mm^2 /s and 0.27 ±0.08,respectively.Meanwhile,these values of the high-grade group were （1.10 ±0.58）＆#215;10 -3 mm2 /s,（1.40 ±0.20×10 ^-3 mm^2 /s,（109.46 ±129.07）×10 ^-3 mm^2 /s and 0.15 ±0.09,re-spectively.The differences in ADC,D value and f value were statistically significant between these two groups （all P〈0.05）;but no statistically significant difference was found in D＊ value between these two groups （P 〉0.05）.The areas under the ROC curve of ADC,D value and f value were 0.768,0.931 and 0.83 respectively.According to maximum Youden index,the optimal threshold value for diagnosis was 1.14×10 ^-3 mm^2 /s,1.59×10^ -3 mm^2 /s,and 0.18,respec-tively.Conclusion The IVIM-DWI can be helpful in preoperative Fuhrman grading of CCRCC,and D value has the best diagnostic efficacy.