弥散张量成像鉴别诊断肾透明细胞癌与肾盂移行细胞癌

Diffusion tensor imaging in differential diagnosis of clear cell renal cell carcinoma and transitional cell carcinoma

目的评价MRI弥散张量成像(DTI)在肾透明细胞癌(ccRCC)与肾盂移行细胞癌(TCC)鉴别诊断中的价值。方法回顾性分析行腹部MR检查、经病理证实为ccRCC及TCC的患者38例(ccRCC 29例,TCC 9例)。患者均行MR T1W脂肪抑制和T2W脂肪抑制序列扫描、LAVA增强扫描、DTI序列扫描(b=0、600s/mm^2)。由2名放射科医师采用AW 4.4工作站采用Functool后处理软件进行图像分析和测量。采用组内相关系数(ICC)检验2名察者所测数据的一致性。ccRCC和TCC ADC值及FA值的比较采用独立样本t检验。采用ROC曲线分析ADC值、FA值对ccRCC与TCC的鉴别诊断效能。结果 2名观察者测量各参数一致性良好(ICC值均>0.75)。ccRCC的ADC值[(2.03±0.49)×10^(-3) mm^2/s]高于TCC[(1.57±0.43)×10^(-3 )mm^2/s;P=0.015)],但ccRCC的FA值(0.24±0.10)低于TCC(0.42±0.22);P=0.002)。ADC值曲线下面积0.761(P<0.05),敏感度和特异度分别为79.3%、77.8%,阈值为1.59×10^(-3) mm^2/s。FA值曲线下面积为0.762(P<0.05),敏感度和特异度分别为66.7%、93.1%,阈值为0.326。结论 MR DTI可有效鉴别ccRCC和肾盂TCC,其中FA值对鉴别两者的特异度较高。

Objective To evaluate the value of ADC and FA of diffusion tensor imaging （DTI） in differentiating clear cell renal cell carcinoma （ccRCC） and transitional cell carcinoma （TCC） of kidney pelvis. Methods Thirty-eight histopathology proven ccRCC and TCC patients （29 cases of ccRCC and 9 cases of TCC） were retrospectively enrolled. All the patients were performed abdominal MR fat saturation T1WI, fat saturation T2WI, LAVA and DTI （b=0, 600 s/mm2）. MR images were reviewed and analyzed by two radiologists in a double-blind manner with the value of ADC and FA measured using the Functool on AW 4.4 workstation. The data of two observers were analyzed with intra-class correlation coefficients （ICC） to assess inter-observer consistency. The differences of ADC values and FA values between ccRCC and TCC were compared by independent t-test. The ROC curves were used to analyze and compare the diagnostic value of DTI in differentiating ccRCC and TCC. Results The inter-observer agreements were good （ICC〉0.75）. The ADC value of ccRCC was statistically higher than that of TCC （[2.03±0.49]×10-3mm2/s vs [1.57±0.43]×10-3 mm2/s, P=0.015）. But the FA value of ccRCC was statistically lower than that of TCC （[0.24±0.10] vs [0.42±0.22], P=0.002）. The area under the ROC curve of ADC was 0.761 （P〈0.05）, and the sensitivity and specificity were 79.3% and 77.8%. The ADC threshold for differentiating ccRCC from TCC was 1.59×10-3 mm2/s. The area under the ROC of FA was 0.762 （P〈0.05）, and the sensitivity and specificity were 66.7% and 93.1%. The FA threshold for differentiating ccRCC from TCC was 0.326. Conclusion MR DTI can effectively discriminate ccRCC and TCC. FA values has good diagnostic specificity in differentiating between ccRCC and TCC.