颅内皮样囊肿自发性破裂的CT及MRI表现

CT and MRI Manifestations of Spontaneous Ruptured Intracranial Dermoid Cyst

目的:分析颅内皮样囊肿自发性破裂的CT及MRI表现。方法:9例经手术和病理证实颅内皮样囊肿自发性破裂的CT、MRI资料,分析其病变部位、大小、形态、与脑积液关系、水肿情况等影像学特点。结果:皮样囊肿6例位于幕上,3例位于幕下,4例位于鞍上池,2例位于鞍旁,3例位于桥小脑角区;5例囊肿形态规则,4例形态不规则,边界均清楚;8例周围无水肿,1例周围有轻度水肿,9例病灶均破裂,目脂滴进入脑脊液内;CT扫描2例呈均匀低密度,7例呈不均匀混杂密度,3例病灶内可见钙化;MRI扫描呈不均质混杂信号,其内均可见短T1脂肪信号,破裂的脂滴均呈短T1、长T2信号,脂肪抑制序列短T1信号均可被抑制;增强扫描6例病灶无强化,3例病灶壁呈明显环形强化,2例破裂脂滴邻近脑膜强化,1例室管膜强化。结论:CT及MRI能够准确显示原发部位的皮样囊肿和破裂后游离于脑脊液内的脂滴,表现具有特征性。

Objective： To investigate CT and MRI manifestations of the spontaneous ruptured in- traeranial dermoid cyst. Methods： Nine patients with spontaneous ruptured intraeranial dermoid cyst confirmed by surgical histopathology were analyzed retrospectively, to analyze intraeranial dermoid cyst locations, size, shapes, relationship to eerebrospinal fluid, edema. Results： Six dermoid cyst result presented at the supratentorium, 3 located at the infratentorium, 4 located at suprasellar cistern, 2 in parasellar and 3 in cerebeflopontine angle. 5 of these cases presented regular shape and 4 irregular shape, all with clear margin. No edema was found around 8 cases, 1 case had mild edema around. The dermoid cyst of 9 cases were ruptured and lipid droplet into the cerebrospinal fluid. CT scan in 2 cases showed low density, 7 cases showed inhomogeneous density. Calcifications were shown in 3 ca- ses. The tumors revealed inhomogeneous intensity on MRI, signal of short T1WI could be found in all 9 cases. Ruptured lipid droplets all presented T1WI and T2WI, and could be suppressed on fat sup- pressed sequence. After intensified scan, 6 cases showed no enhancement, and ring-shaped intense enhancement showed in 3 cases. Additionally, meningeal or ependymal enhancement were found in 3 cases. Conclusions： The imaging characteristic of the spontaneous ruptured intracranial dermoid cyst were specific. CT and MR could accurately detect the extent of tumor involvement.