肾盂旁囊肿的CT诊断及分型

CT Features of Parapelvic Cyst

目的分析肾盂旁囊肿的CT表现特征,探讨CT增强多期扫描对该病的诊断价值。方法回顾性分析和总结71例肾盂旁囊肿的CT表现,其中男39例,女32例,年龄31～86岁,平均63岁。71例均行CT平扫和增强扫描。对肾盂旁囊肿单、双侧肾盂分布以及并发积水、结石情况在两种分型间的差异行χ2检验,统计学软件为SPSS 13.0,P<0.05为差异有统计学意义。结果将其CT表现分为Ⅰ、Ⅱ两型:Ⅰ型(单发类圆形)囊肿41例,多呈位于单侧肾窦内或由肾窦外侵入肾窦、膨胀性生长的单发圆形或类圆形囊样低密度影;Ⅱ型(多发"蔓藤"状)囊肿30例,多为位于双侧肾窦内、围绕肾盂"匍匐"状延伸的多发"蔓藤"状或不规则形囊样低密度影。Ⅱ型双侧发病率明显高于Ⅰ型(χ2=46.49,P<0.001);Ⅰ型较Ⅱ型更易伴发肾盂积水(χ2=8.52,P<0.001);两者伴肾结石的发生率无明显差别(χ2=0.02,P=0.901)。在CT平扫时,肾盂旁囊肿常因紧邻肾盂,缺乏密度对比以及无明显肾窦脂肪衬托或分隔,易误诊为肾盂积水,故CT增强多期扫描尤其是延迟期必不可少。结论 CT分型有助于理解和掌握肾盂旁囊肿的CT表现。CT增强多期扫描对确诊及指导治疗有极其重要的价值。

Objective To analyze the CT features of parapelvic cyst in muhi-phase enhanced CT scan. Methods Seventy one patients with parapelvic cysts, including 39 males and 32 females, aged from 31 to 86 years, mean 63 years were collected in the study. CT features of parapelvic cysts were retrospective analyzed. All The 71 patients underwent plain and enhanced CT scan. The Chi-square test was performed to test the difference between the two types with regard to the lesion site and the complication of hydronephrosis and stone. Results CT features of parapelvic cyst were divided into two types： type Ⅰ （single round like cyst ,n =41 ）, showed single round cystic low density lesions with expansive growth in the unilateral renal sinus, type Ⅱ （ multiple vine like cyst, n = 30） showed multiple vine like cystic low density lesions located at the bilateral renal sinus creeping around the pelvis. Type Ⅱ cysts were more likely involved bilateral renal sinus than typeⅠ（P 〈 0.001 ）. TypeⅠ cysts were more likely complicated by hydronephrosis than Type Ⅱ （P 〈 0. 001 ）. There is no significant difference of incidence of kidney stones between two types （P = 0. 901 ）. On plain CT images, parapelvic cysts were easily mistaken for hydronephrosis because of close location to the renal pelvis, lack of density contrast, no sufficient renal sinus fat to provide a contrast. Therefore multi phase enhanced CT was necessary, especially the delay phase. Conclusion CT classification helps to understand the CT features of parapelvic cysts. Muhi-phase enhanced CT is significant for the diagnosis and management of parapelvic cysts.