3.0T MR弥散加权成像在肾脏肿块型病变中的诊断价值

MR diffusion weighted imaging in diagnosis and differential diagnosis of renal masses

目的评价3.0T MR弥散加权成像(diffusion weighted imaging,DWI)序列在肾脏肿块型病变的诊断及鉴别诊断价值。方法回顾性分析152例肾脏肿块型病变,采用3.0T MR行b值=800 s/mm2DWI检查,除肾囊肿(包括单纯囊肿及复杂囊肿)外,所有肿瘤均经手术病理或穿刺活检证实,对病灶的DWI信号特点进行记录和分析,计算DWI诊断肾脏良恶性肿瘤的灵敏度、特异度、阳性预测值、阴性预测值,比较所有病灶的ADC值。结果与癌周组织相比,肾细胞癌表观弥散系数(apparent diffusion doefficient,ADC)值差异有统计学意义(P<0.05);与非透明细胞癌相比,肾透明细胞癌ADC差异有统计学意义(P<0.05)。肾细胞癌、肾盂癌、肾脓肿、肾血管平滑肌脂肪瘤、肾囊肿及肾细胞癌囊变区各组ADC值差异有统计学意义(F=129.71,P=0.000),其中肾细胞癌、肾血管平滑肌脂肪瘤及肾盂癌组的ADC值两两之间差异有统计学意义(P<0.01),肾细胞癌及肾盂癌的ADC值统计学上均低于良性病变(肾脓肿及肾血管平滑肌脂肪瘤),肾盂癌的ADC值最低,肾血管平滑肌脂肪瘤的ADC值最高。良性囊肿性病变及肾细胞癌囊变区的ADC值差异有统计学意义(t=3.756,P=0.000)。其中透明细胞癌临床各分期两两比较发现,Ⅰ期与Ⅲ、Ⅳ期及Ⅱ期与Ⅲ、Ⅳ期相比,差异有统计学意义(P<0.01),Ⅲ期及Ⅳ期的ADC值较低。结论高b值DWI鉴别肾脏良恶性肿瘤有较高的准确率,结合量化分析ADC值能够更好的显示肾脏肿块的病变特征,在肾脏肿块的鉴别以及恶性程度评估等方面有着重要的意义。

Objective To evaluate the application of 3. 0 T MR diffusion weighted imaging（ DWI）in diagnosis and differential diagnosis of renal masses. Methods The images of 152 patients with renal masses receiving MR DWI scans with b value = 0,800 s / mm^2 with a 3. 0T scanner were analyzed retrospectively. All masses were confirmed by pathology except for renal cysts（ including simple and complex cysts）. The sensitivity,specificity,accurate rate,positive predictive value and negative predictive value of ADC values in differentiating benign from malignant tumors and DWI features of all lesions were analyzed. Results There were significant differences in ADC values between renal cell carcinoma and peritumoral tissues,between renal clear cell carcinoma and non-clear carcinoma. LSD test showed that there were significant differences in ADC values among renal cell carcinoma,renal angiomyolipoma and carcinoma of renal pelvis（ P〈 0. 01）. ADC values of renal cell carcinoma and carcinoma of renal pelvis were significantly different from benign tumors（ P 〈0. 01）,renal pelvis carcinoma had the lowest ADC value and renal angiomyolipoma had the highest value. The ADC values of benign renal cystic lesions and cystoid variation in renal cell carcinoma were significant different. LSD test showed that there were significant differences in ADC values between phase I and Ⅲ/Ⅳ,phase ⅡandⅢ/Ⅳ（ P 〈0. 01）; and phase Ⅲ and Ⅳ had the lowest ADC value. Conclusion The results shows that DWI has high accuracy rate for differentiating benign from malignant urothelial carcinoma with high b value. The quantitative analysis of ADC value can showthe lesions more accurately,and may be of value in differential diagnosis of malignant from benign lesions and the evaluation of malignant degrees.