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MRI Diagnosis of Ruptured Dermoid Cyst in Intraspinal Canal ――A Report of 13 Cases

程敬亮，吉金钟，李树新，任翠萍，王声鼎，李荫太，高剑波

CHENG Jingliang，JI Jinzhong，LI Shuxin，et al.

MRI Division，No. 1 Affiliated Hospital，Henan Medical University，Zhengzhou，Henan Province 450052，P. R. China

Abstract

　　Objective：To evaluate MRI in the diagnosis of ruptured dermoid cyst in the intraspinal canal （RDCIC）.

　　Materials and Methods：Thirteen patients with surgico－pathological]y proved RDCIC，located below T12，were collected. Nine lesions were intramedullary，and four were extramedllary and intradural. Cranial and full spinal MRI scanning with SE T1WI and T2WI were performed in all eases，additional fat－suppression sequences of the spine were done in 7 cases. Cranial CT scanning was made in 5 cases.

　　Results：Lipid droplets in cerebral subarachnoid space or ventricles were seen in all extramedullary intradural RDCIC on both CT and MRI. Lipid droplets within central canal of spinal cord were seen in all 9 eases of intramedullary RDCIC on MRI，in 4 of them intraventrlcular lipid droplets were found. On MRI lipid droplets at cerebral bottom and posterior fossa were displayed in 5 eases，while on CT lipid droplets could be revealed only in 2 cases. The lipid droplets showed hyperlntensity on SE T1WI，a little lower signal intensity on T2WI，and hypointensity on fat－suppression sequence. The lipid droplets showed fatty density on CT scan with a value of － 150 ～ － 20 Hu.

　　Conclusion：MRI is the most effective means for the diagnosis of RDCIC，it is superior to CT in demonstrating the lipid droplets distributing in the subarachnoid space，ventricles and central canal of the spinal cord，and in distinguishing the lipid droplets from gas，iodized oil or blood clot.

　　Key words：Spine　Dermold cyst　MRI

　　椎管内皮样囊肿少见，发生破裂者罕见。自1992年Brasi等^[1]首次报道1例椎管内皮样囊肿破裂（rup tureddermoid ofintraspinal canal，RDIC）以来，仅有少数个案报道^[2，4]。笔者搜集我院1992年10月－2000年8月经手术和MRI检查证实的13例RDIC报道如下，旨在探讨RDIC的MRI诊断价值。

　　1. 材料与方法

　　13例RDIC患者中男6例，女7例，年龄21－50岁，平均35岁。全部患者均有不同程度脊髓和/或马尾神经损害的临床表现。3例有明显脑膜炎症状与体征，脑脊液检查排除了感染性脑膜炎，其中1例有腰部外伤史，伤后3天即出现头痛，按脑膜炎和颅高压治疗1个月无效行脑和脊柱MRI检查才明确诊断；另2例有脑膜炎表现者分别按感染性脑膜炎治疗2周和4周，后确诊为RDIC所致的化学性脑膜炎。13例RDIC原发灶即椎管内皮样囊肿均经手术证实，其中4例行MRI检查前2－9年已行椎管内皮样囊肿切除术，但 MRI检查时均发现皮样囊肿复发，2例再行手术切除皮样囊肿。全部患者均未做过X线脊髓造影、CT脊髓造影和脑池、脑室造影检查。

　　13例RDIC患者均行脑和全脊柱MRI，5例行脑CT检查，1例行颈椎CT。脑CT扫描仪均为第三代，采用横断面，层厚8～10mm。MRI扫描均采用Siemens 1.0T超导型MR机（Impact）。脑MRI均行SE序列横断面T1WI、T2WI和矢状面T1WI扫描，横断面层厚7mm，矢状面层厚5mm。脊柱MRI均行全脊柱扫描，13例 RDIC患者均行SE序列矢状面T1WI、T2WI和横断面 T1WI扫描，3例行冠状面T1WI，矢状面层厚3～4mm，横断面和冠状面层厚5～6mm，7例有脂肪抑制序列。脊柱MRI扫描分别使用颈线圈和方形脊柱表面线圈。