肾嗜酸细胞瘤的影像学诊断

目的:探讨肾嗜酸细胞瘤(RO)的影像学表现,以提高对其诊断的准确性。方法:回顾性分析经病理证实的12例RO患者的影像资料。12例均行MSCT平扫及多期增强扫描,包括肾皮质期、髓质期和排泄期(5例)增强扫描;有3例同时行MRI检查。结果:CT平扫示12例病灶均为单发,7例位于左肾,5例位于右肾,最大径2.0~11.6cm,平均5.8cm,<3.0cm者3例。增强扫描:肾皮质期示10例病灶明显强化,其中8例强化低于肾皮质,2例强化接近于肾皮质;肾髓质期示7例病灶强化程度下降并低于肾脏髓质的密度,3例病灶持续强化、于排泄期见密度开始下降,2例病灶在皮质期~排泄期表现为持续强化;6例病灶内可见星芒样瘢痕,8例有完整包膜,3例可见钙化。3例病灶于MRIT1WI上呈等、低信号,T2WI呈相对均匀的高信号,3例均见完整包膜。结论:RO的影像学表现有一定特征性,多表现为增强后均匀强化,无囊变或坏死,T2WI上可见完整的低信号包膜,有助于同各类型肾癌鉴别。

Imaging Diagnosis of Renal Oncocytoma

Objective:To study the imaging features of renal oncocytoma (RO) and to improve the diagnostic accuracy.Methods:The imaging features of 12 pathology proved ROs were reviewed retrospectively.All patients underwent MSCT including pre-contrast as well as post-contrast (cortico-medullary phase,parenchymal phase) scanning,five patients had excretory phase additionally.Three patients had MR examination.Results:On plain CT images,all patients had solitary lesion,the location of RO were in left kidney (n=7) and right kidney (n=5).The maximum dimension of lesion ranged from 2.0~11.6cm (average 5.8cm),three lesions were less than 3.0cm.Ten lesions showed obvious enhancement on the cortico-medullary phase,the attenuation in eight of which were lower than the adjacent renal cortex,two lesions showed iso-attenuated when compared with renal cortex.On the parenchymal phase,seven lesions became hypo-attenuated when compared with renal medulla and three lesions showed continuous enhancement but the attenuation declined at the excretory phase.Two lesions enhanced continuously from the cortico-medullary phase to the excretory phase.Central stellate scar was found in six lesions and complete psudocapsule was observed in eight,calcification was observed in three lesions.Of the three lesions underwent MR examination,which showed iso-/hypo-intensity on T1WI and relatively homogeneous hyperintensity on T2WI.Complete hypointense psudocapsule on T2WI was revealed in all three lesions.Conclusion:Most of the ROs showed certain imaging characteristics,including homogenous enhancement on post-contrast images,without necrosis or cystic changes,complete hypointense psudocapsule on T2WI,which are helpful in the differential diagnosis with all subtypes of renal cell carcinoma.