桥小脑角囊性病变的MRI诊断及鉴别诊断

MRI diagnosis and differential diagnosis of cystic lesions in the cerebellopontine angle

目的:探讨MRI对桥小脑角(cerebellopontine angle,CPA)囊性病变的诊断及鉴别诊断价值。方法:搜集本院30例经病理证实的CPA囊性病变患者的MRI资料,回顾性分析这些病变的MRI表现,并和手术病理结果作对照分析。结果:30例病变中右侧CPA 16例,左侧10例,双侧4例;位于CPA池内24例,脑内6例。其中表皮样囊肿12例,多呈不规则形沿蛛网膜下腔匐行生长,并包埋邻近的神经血管,DWI以高信号为主,增强后无强化;蛛网膜囊肿5例,信号与脑脊液一致,增强后无强化;皮样囊肿3例,呈长T1长T2信号2例,混杂信号1例,2例DWI呈高信号,均无强化表现;囊性听神经瘤6例,呈单房或多房改变,增强后囊壁及分隔均见强化,其中3例患侧内听道扩大、听神经增粗并强化;血管母细胞瘤4例,均为大囊小结节型,附壁结节明显强化。与手术及病理对照,MRI对CPA囊性病变的定位、定性诊断准确率分别为96%、92%。结论:MRI对CPA囊性病变的定位及定性诊断准确率高,具有重要的诊断及鉴别诊断价值。

Objective： To investigate the value of magnetic resonance imaging（ MRI） in diagnosis of cystic lesions in cerebellopontine angle（ CPA）. Methods： The MRI manifestations and pathology of 30 patients with CPA cystic lesions confirmed by pathology were analyzed with contrast retrospectively. Results： In 30 cases,16 cases located at right CPA and 10 left and 4 bilateral. 24 cases were in the CPA cistern,6 were intracephalic lesions.Epidermoid cyst（ n = 12） manifested irregular shape and grew serpiginously along the subarachnoid embedding adjacent neurovascular. They showed hyperintense on DWI and no enhancement after gadolinium injection. The signal intensities of arachnoid cysts（ n = 5） matched those of cerebrospinal fluid on all sequences,did not enhance after contrast administration. Dermoid cyst（ n = 3） appeared hypointense on T1 WI,hyperintense on T2 WI and DWI（ n =2） and mixed signal（ n =1）,with no enhancement. Cystic acoustic neuromas（ n =6） appeared as monolocular or multiocular lesions with enhanced cyst wall and septations. 3 cases confessed enlarged internal auditory canal and thicking auditory nerve of injury side. Hemangioblastoma（ n = 4） had the characteristics of big cyst with marked inhanced small nodular. Contrast to operation and pathology,the accuracy rates of level diagnosis and qualitative diagnosis by MRI were 96% and 92% respectively. Conclusion： The MRI accuracy rates of level diagnosis and qualitative diagnosis to CPA cystic lesions are high. MRI has important value in diagnosis and differential diagnosis of CPA cystic lesions.