T2WI灰阶比值在肾透明细胞癌和乏脂性血管平滑肌脂肪瘤鉴别诊断中的价值

目的 :探讨T2WI灰阶比值对肾透明细胞癌(Clear cell renal cell carcinoma,CCRCC)和乏脂性血管平滑肌脂肪瘤(Angiomyolipoma with minimal fat,AMLmf)鉴别诊断的价值。方法:回顾分析经手术病理证实的最大径≤4.0 cm的46例46枚CCRCC与32例35枚AMLmf的T2WI图像,通过RADinfo阅片系统灰阶直方图软件,测量并计算肾脏肿瘤/肾皮质和肿瘤/脾实质的灰阶比值。通过受试者工作特征(ROC)曲线获得鉴别CCRCC与AMLmf最佳比值的阈值。结果:46枚CCRCC和35枚AMLmf中,瘤/肾比值、瘤/脾比值分别为(1.021±0.206)与(0.710±0.159)(t=7.420,P<0.001)、(1.634±0.331)与(1.140±0.272)(t=3.889,P<0.001)。瘤/肾比值、瘤/脾比值诊断CCRCC的曲线下面积和最佳阈值分别为0.891和0.904、0.817和1.123,相应的敏感度和特异度分别为76.1%和91.4%、87.0%和71.4%。随着两个比值的升高,诊断CCRCC的敏感度减低,特异度升高。两者联合的敏感度为69.6%,特异度为94.3%。结论:T2WI灰阶比值能客观、准确以及定量地鉴别CCRCC和AMLmf,瘤/肾比值具有较高的特异度,瘤/脾比值有较高的敏感度,联合两者比值鉴别诊断则具有更高的特异度,减少误诊率的发生。

The value of T2WI grayscale ratio in the differentiation of clear cell renal carcinoma from angiomyolipoma with minimal fat

Objective: To investigate the value of T2 WI grayscale ratio in the differential diagnosis of small clear cell renal cell carcinoma(CCRCC) and angiomyolipoma with minimal fat(AMLmf). Methods: T2 WI data of 46 cases surgical which pathological comfirmed CCRCC and 32 cases of proven 35 AMLmf the diameter ≤4.0 cm were restrospectively analyzed. The grayscale value of renal tumor to kidney cortex and tumor to spleen were measured and calculated by RADinfo Reading System. The threshold value of the optimal ratio to identify CCRCC and AMLmf was obtained through the ROC curve. Results:In 46 CCRCC and 35 AMLmf, the tumor/kidney ratio and tumor/spleen ratio were 1.021±0.206 and 0.710±0.159(t=7.420, P<0.001), 1.634±0.331 and 1.140±0.272(t=3.889, P<0.001), respectively. The area under the curves and optimal threshold of tumor/kidney ratio and tumor/spleen ratio in the identification of CCRCC and CCRCC respectively were 0.891 and 0.904, 0.817 and 1.123, respectively. And the corresponding sensitivity and specificity were 76.1% and 91.4%, 87.0% and 71.4%. While these ratios were increasing, the sensitivity to diagnose CCRCC decreases and the specificity increases. In combination with tumor/kidney ratio and tumor/spleen ratio, the sensitivity and specificity were 69.6% and 94.3%. Conclusion: T2 WI grayscale ratio can identify CCRCC and AMLmf objectively, accurately and quantitatively. The tumor/kidney ratio has a high specificity,and the tumor/spleen ratio has a high sensitivity. The combination of the two ratios has higher specificity, which reduce the incidence of misdiagnosis.