肾嫌色细胞癌:动态增强CT及MR表现

目的:分析肾嫌色细胞癌的影像学表现及其血液动力学特征与病理的关系,提高诊断准确性.方法:经手术病理证实的肾嫌色细胞癌16例,术前经螺旋CT或多层螺旋CT平扫、皮髄交界期和实质期扫描,注射流率3 ml/s;3例经MRI SE T1WI、T2WI和扰相梯度回波动态增强成像.仔细复习CT和MRI扫描结果并与手术病理作回顾性对照分析.结果:16例嫌色细胞癌中肿瘤呈球形14例,椭圆形2例,边缘光整.所有肿瘤平扫软组织密度均匀,3例可见钙化,1例瘢痕伴钙化.肿瘤直径3.5～13.0cm,平均7.6cm.实质性肿瘤15例,1例实质期增强可见小囊变.肿瘤平扫CT值22.7～34.2 HU,平均27.1 HU;动态增强皮髓交界期CT值30.4～71.8 HU,平均43.3 HU;实质期CT值32.9～82.4 HU,平均51.7 HU.4例可见轮辐状强化.3例行MRI检查,MR T1WI为略低信号,T2WI为略高信号,1例可见中心轮辐状瘢痕,皮髄交界期轻中度强化,实质期强化相仿.结论:肾嫌色细胞癌多位于髓质,瘤体呈球形,坏死囊变很少见,瘤肾分界截然;皮髄交界期强化低于、等于或高于肾髓质,但明显低于肾皮质,实质期强化多低于或等于皮髄交界期,少数高于皮髄交界期;轮辐状强化或轮辐状中心瘢痕超过1/3.

CT and MR Findings of Chromophobic Cell Renal Carcinoma

Objective:In order to enhance the imaging diagnostic knowledge of chromophobic cell renal carcinoma,the correlation of the CT and MR signs to the relative pathological findings were retrospectively studied.Methods:16 cases with surgically and pathologically confirmed chromophobic cell renal carcinoma were collected.Pre-operative plain and dynamic CT examinations using a spiral CT scanner in all the 16 cases,and the same of MR scans in 3 cases were performed.The CT and MR findings were retrospectively reviewed and analyzed;the correlation of the imaging signs to the relative pathological findings was studied.Results:In the 16 cases of tumors,14 round and 2 oval solid masses with clear contours were found.All the tumor masses showed homogeneous soft-tissue density/signal intensity on CT/MR plain scans,additionally,3 cases with tumor calcification and 1 case with tumor scars as well as calcification were seen.The dimensions of the tumors were measured as 3.5~13.0cm in diameters with a mean of 7.6cm.On dynamic contrast enhanced scans of CT and MRI,substantial tumor masses were demonstrated in 15 cases,while 1 case with mini-cystic changes was seen on nephrogram phased images.CT values of tumor masses on plain scans showed 22.7~34.2HU,with a mean of 27.1.On dynamic CT scans,the CT values at corticomedullary and nephrogram phases were 32.9~82.4HU(with a mean value of 43.3HU)and 32.9~82.4HU(with a mean value of 51.7HU)respectively,meanwhile,wheel-spoke like enhancement of the tumors was found in 4 cases.On the MR scans of the 3 cases,tumor masses presented mildly low signal intensity on T1WI and slightly high signal intensity on T2WI images.There was also tumor central wheel-spoke like scar in 1 of the cases.On dynamic contrast enhanced MR scans,tumor masses showed mildl to moderate enhancement on CMP images and revealed similar extent of enhancement on NP scans.Conclusion:The CT and MRI features of chromophobic cell renal carcinoma were generally summarized as follows:most of the tumors situated at medulla of the kidneys,round in shape,tumor necrosis and cystic changes rarely seen and well-defined interfaces with their surrounding kidney usually found.On dynamic scans,the tumors might enhance less than,equal to or more intense than the renal medulla,while significantly less intense than the renal cortex on CMP images;on NP images lower or similar extents of contrast enhancement in most of the tumors,except a few of them with higher enhancement,were demonstrated in comparison with those shown on CMP images.Tumors with wheel-spoke like enhancements or scars were found in over one-thirds of the cases.