颅内畸胎类肿瘤自发性破裂的CT与MRI诊断

CT and MRI Diagnosis of Spontaneously Ruptured Intracranial Terato-dermoid Tumors

目的探讨颅内畸胎类肿瘤自发性破裂的CT与MRI影像特征。方法回顾性总结经手术病理证实的6例颅内畸胎类肿瘤自发性破裂的CT及MRI资料并结合文献分析其影像学特征。结果 6例病变中,皮样囊肿3例,畸胎瘤2例,表皮样囊肿1例,均为自发性破裂,影像学上见原发病灶在MRI呈信号不均的囊性病灶,CT均见到脂肪成份,磁共振波谱成像(MRS)可见特征性的脂质高峰;破裂的囊内容物向邻近蛛网膜下腔延伸,呈"飘带征"改变,蛛网膜下腔、脑室内可见多发短T1信号脂滴,脂肪抑制序列短T1信号均被抑制。结论颅内畸胎类肿瘤自发性破裂具有特征性影像学表现,CT结合磁共振T1加权像、脂肪抑制成像及波谱成像对该类病变的诊断具有重要价值。

Objective To study the characteristics of intracranial Terato-dermoid tumors ruptured spontaneously on the CT and MRI. Methods CT and MRI data of 6 cases of ruptured intracranial Terato-dermoid tumors were summarized and analyzed with literatures, all of the cases were confirmed by pathology. Results 3 cases were dermoid cyst, 2 cases were teratoma and 1 case was epidemoid cyst. The rupture of the lesions were all occurred spontaneously. The signal intensity of the primary tumors on MRI was heterogeneous and cystic, and low density of fat could be found on CT. Magnetic resonance spectroscopy （MRS） imaging perfrrmed characteristic lipid peak. Rupture of the cyst contents to the adjacent subarachnoid space could be presented with a ＂Ribbon＂ sign, the characteristic lipid material could be found in the subarachnoid space and ventricles. Fat droplets which 9erformed low density on CT were hyperintense in Tl-weighted magnetic resonance im- ages （TIWI） and could be suppressed in fat-saturated MR sequences. Conclusion There are characteristic imaging features of spontaneously ruptured intracranial Terato-dermoid tumors. CT combined with T1WI, fat-saturated sequences and MRS are of great value for diagnosis.