第四脑室室管膜瘤的CT、MRI影像表现

CT and MRI Features of the Fourth Ventricle Ependymoma

目的探讨第四脑室室管膜瘤的CT、MRI特征,以提高对该病的诊断和鉴别诊断水平。方法搜集2008年4月至2011年7月在北京天坛医院经手术病理证实的33例第四脑室室管膜瘤患者资料,男20例,女13例,年龄2～68岁,回顾性分析其CT和(或)MRI表现。结果 33例中有12例同时行CT、MRI,8例单独行CT检查,13例单独行MRI。20例CT检查中,病灶密度以等/略高/略低密度为主,CT值范围21～48 HU,有10例发现点片状钙化,有13例发现"浇注"现象,术前CT准确诊断本病者3例。25例行MRI常规平扫加Gd-DTPA增强扫描,病灶大部分呈T1WI稍低信号、T2WI稍高信号,25例均可发现不同程度的"浇注"现象,21例肿块呈不均匀轻中度强化,3例中重度强化,1例无明显强化,23例MRI术前确诊。33例中共有22例肿块内有囊变区,12例肿块与脑干分界欠清晰,29例继发脑积水,3例重度脑积水,15例伴有室旁间质水肿,19例肿块几乎占满第四脑室。结论第四脑室室管膜瘤的CT、MRI表现有一定特征性,MRI是目前诊断该病的最佳方法,综合分析CT、MRI表现,可提高诊断准确率。

Objective To study the CT and MRI features of ependymoma in the fourth ventricle. Methods 33 patients with fourth ventricle ependymoma （20 males, 13 females, ging from 2 to 68 years） confirmed by surgery and pathology were collected from April 2008 to July 2011 in Beijing Tiantan Hospital,. The CT and （or） MRI features were retrospectively analyzed. Results There were 12 patients underwent both CT and MRI, 8 cases underwent CT scan and 13 cases underwent MRI alone. On CT images （20 cases）, the lesions showed equal, slightly high or slightly low density masses with CT value range of 21 -48 HU. Punetate calcifications were found in 10 cases, ＂ Casting＂ phenomenon in 13 cases, and 3 cases were accurately diagnosed preoperatively. On plain and enhanced MRI images （25 cases）, the lesions showed slight hypointensity in T, WI and slight hyperintensity in T2WI. ＂Casting＂ phenomenon in varying degrees was found in 25 cases. The images of 21 cases showed mild or moderate heterogeneous enhancement 3 eases showed serious enhancement, and I case showed no enhancement. There were 23 cases accurately diagnosed preoperatively. Among the total 33 cases, cystic areas were showed within the tumors in 22 cases , unclear boundaries with brain stem in 12 eases, secondary hydrocephalus in 29 cases, serious hydrocephalus in 3 cases, paraventrieular interstitial edema in 15 eases, masses filled the fourth ventricle in 19 eases. Conclusion Ependymoma in the fourth ventricle shows certain CT and MRI features. MRI is the best method to diagnose the disease. A comprehensive analysis of CT and MRI performance could improve the diagnostic accuracy.