肾嗜酸细胞腺瘤的MRI特征

目的探讨肾嗜酸细胞腺瘤（renal oncocytoma,RO）的MRI特征。方法回顾性分析9例经病理证实为RO的MRI资料（MRI平扫及动态增强扫描）。结果 1病灶均为圆形或类圆形,边界清晰;位于左肾者6例,右肾3例,平均直径3.8cm。所有病例均起自肾实质,7例突出于肾轮廓之外,2例邻近肾门区。2 MRI征象：9例T1WI同相位均呈低或等信号,7例反相位无明显信号减低,2例反相位见片状信号减低;抑脂T2WI均呈稍高或高低混杂信号;DWI呈不均匀稍高信号;3例见＂星芒状＂纤维瘢痕。动态增强：7例动脉期中度不均匀明显强化,其中6例静脉期、延迟期持续强化,1例出现＂节段性强化逆转＂征象,1例静脉期廓清。2例动脉期轻度强化,静脉期及延迟期持续轻度强化。2例中心瘢痕动脉期无强化,静脉期轻度强化,延迟期呈稍低信号;1例中心瘢痕动脉期明显强化,静脉期持续强化,延迟期呈等信号。4例有包膜并可见延迟强化。结论 RO的MRI表现具有一定的特征,仔细分析其MRI征象,有助于术前做出正确诊断。

The MRI Features of Renal Oncocytoma

Objective To investigate the MRI features of renal oncocytoma（RO）. Methods MRI findings of 9 cases with RO which proved by pathology were analyzed retrospectively. All were performed with MRI plain and dynamic enhanced. Results 1 All lesions were round or oval with clear boundaries. There were 6 cases in left kidney, 3 cases in right kidney, and the average diameter was 3.8 cm. All cases originated in the renal cortex, 7 cases protruded outside of renal outline, 2 cases closed to renal hilum.2 MRI findings： All cases showed slightly lower or equal signal on T1 WI in phase, 2 cases signals could be seen reduced with sheet on out-phase, 7 cases without reduction; all showed slightly higher or heterogeneous signal on fat suppression T2 WI and uneven slightly higher on DWI; 3 cases were seen ＂stellate＂ fibrous scar. Dynamic enhancement： 7 cases significantly enhanced at arterial phase, 6 cases continued to strengthen at portal venous phase and delayed phase, 1 case showed ＂segmental strengthening reversal＂ signs, 1 case clarified at portal venous phase. 2 cases slightly enhanced at arterial phase, both continued to strengthen at venous phase and delay period. 2 cases of central scar no enhanced at arterial phase, mildly enhanced at venous phase, and showed slightly lower signal at delay period. 1 case of central scar significantly enhanced at artery period and continued to strengthen at venous phase, showed equal signal at delayed phase. 4 cases with enveloped and enhanced. Conclusion The MRI findings of RO had certain characteristics, and attentive analysis the MRI findings helps to make correct preoperative diagnosis.