双能CT碘浓度及碘廓清率在肾癌与肾血管平滑肌脂肪瘤鉴别诊断中的应用价值

The Values of Dual-Energy CT with Iodine Concentration and Iodine Washout Percentage in the Differential Diagnosis of Renal Cell Carcinoma and Renal Angiomyolipoma

目的探讨双能CT碘浓度及碘廓清率在肾癌(RCC)与肾血管平滑肌脂肪瘤(RAML)鉴别诊断中的应用价值。方法临床拟诊肾脏肿瘤的患者行双能量CT增强扫描,追踪并收集RCC及RAML病例的CT影像资料,总结RCC与RAML两组间碘浓度及碘廓清率的不同特点,为两者的鉴别诊断提供依据。结果皮髓(CM)期RCC与RAML两组间腹主动脉碘浓度比较差别无统计学意义(t值=0.516,P=0.609)。实质(NP)期RCC与RAML两组间腹主动脉碘浓度比较差别无统计学意义(t值=0.450,P=0.656)。CM期病灶碘浓度RCC高于RAML(Z值=-2.361,P=0.018),CM期病灶碘浓度鉴别RCC与RAML的曲线下面积为0.756(P=0.018),以6.45mg/mL为阈值鉴别RCC与RAML的灵敏度和特异度分别为66.7%、90%,Youdern指数为0.567,总体诊断准确率为72.97%(27/37)。NP期病灶碘浓度RCC与RAML差别无统计学意义(t值=1.189,P=0.242)。RCC碘廓清率大于RAML组(Z值=-2.738,P=0.006)。碘廓清率鉴别RCC与RAML的曲线下面积为0.796(P=0.006),以42.5%为阈值鉴别RCC与RAML的灵敏度和特异度分别为74.1%、80%,Youdern指数为0.541,总体诊断准确率为75.68%(28/37)。结论RCC CM期病灶碘浓度高于RAML,且碘廓清率大于RAML。CM期病灶碘浓度和碘廓清率是鉴别RCC与RAML的有效指标。

Objective To investigate the values of dual-energy CT with iodine concentration and iodine washout percentage in the differential diagnosis of renal cell carcinoma(RCC)and renal angiomyolipoma(RAML).Methods To apply dual-energy enhancedCT scanning to patients who clinically diagnosed as renal tumor,track and collect CT data of RCC and RAML cases,summarize different characteristics of iodine concentration and iodine washout percentage between RCC and RAML groups,provide proof for the differential diagnosis of these two groups.Results There was no statistically significant difference in iodine concentration of abdominal aorta between RCC and RAML groups both on the corticomedullary(CM)phase(t=0.516,P=0.609)and the Nephrographic(NP)phase(t=0.450,P=0.656).The iodine concentration in the lesions of RCC was higher than that of RAML on CM phase(Z=-2.361,P=0.018).Using the cutoff of 6.45mg/mL,it had area under ROC of 0.756(P=0.018),sensitivity of 66.7%,and specificity of 90%,the Youdern index of 0.567,and the overall accuracy of 72.97%(27/37).There was no statistically significant difference in iodine concentration of lesions between RCC and RAML groups on NP phase(t=1.189,P=0.242).Iodine washout percentage in RCC was higher than in RAML(Z=-2.738,P=0.006).Using the cutoff of 42.5%,it had area under ROC of 0.796(P=0.006),sensitivity of 74.1%,and specificity of 80%,the Youdern index of 0.541,and the overall accuracy of 75.68%(28/37).Conclusion The iodine concentration in the lesions of RCC is higher than that of RAML on CM phase.Iodine washout percentage in RCC is higher than in RAML.The iodine concentration in the lesions on CM phase and iodine washout percentage are valuable for the differential diagnosis between RCC and RAML.