桥小脑角区肿瘤的MRI诊断

MRI Diagnosis of the Pontocerebellar Tumour

目的：分析桥小脑角区肿瘤的ＭＲＩ 表现，提高桥小脑角区肿瘤的ＭＲＩ 诊断准确率。材料和方法：搜集一组经手术及病理证实的桥小脑角区肿瘤４５ 例，全部行ＭＲＩ 平扫及增强检查。结果：本组４５ 例中听神经瘤１８ 例，脑膜瘤８ 例，三叉神经瘤６ 例，胆脂瘤３ 例，血管母细胞瘤４ 例，海绵状血管瘤４ 例，脊索瘤２ 例。肿瘤位于左侧桥小脑角区占６９ ％ ，位于右侧桥小脑角区占３１ ％ 。８７ ％ 的肿瘤呈园形或类园形，轮廓较清晰，占位效应明显，在Ｔ１ ＷＩ上多呈低等信号，Ｔ２ ＷＩ 上多呈高信号，增强后呈明显均匀强化。但各种肿瘤又有其特征性ＭＲ 改变，如三叉神经瘤跨中后颅窝生长，胆脂瘤沿脑池生长，听神经溜，三叉神经瘤，血管母细胞瘤多见囊变、坏死，海绵状血管瘤多见出血，脑膜瘤、脊索瘤有不规则钙化，多数脑膜瘤增强后见脑膜尾征。ＭＲＩ 对桥小脑角区肿瘤的检出率、定位率、定性率分别为１００ ％ 、１００ ％ 、９０ ％ 。结论：ＭＲＩ 对桥小脑角区肿瘤的诊断及鉴别诊断有重要价值。

Purpose:We could increase the diagnostic accuracy of the pontocerebellar tumour by analysing the MRI images of the pontocerebllar tumours.Materials and Methods:We collected 45 cases of the pontocerebellar tumours verified by operation and pathology. All of these cases had undergone MRI scans and contrast enhancement. Results:In 45 cases,18 were acoustic tumours, 8 of meningiomas, 6 of trigeminal tumours. 3 of cholesteatoma,4 of hemangioblastoma,4 of cavernomas and 2 of chordomas.The proportion of tumours in the left of pontocerebellae aera was 69% while in the right of pontocerebllar area is 31%. There were 87% tumours to be round or oval, clear outline and evident mass effect.Most of them was low or equal signal on T1WI,high signal on T2WI.They could be enhanced conspicuously after contrast.But all kinds of tumours have their special MRI characteristics.For instance,trigeminal tumour developed between cranialis fossae,cholesteatoma developed along cistermas,acoustic tumour,trigeminal tumour and hemangioblastoma could display cystic change and necrosis.Most of cavernomas could display bleed.Meningioma and chordoma could show irregular calcification.Most meningioms revealed“tail sign' after contrast enhancement.The accuracy rates of detection,localization and qualification of the pontocertbellar tumour were 100%,100%,90%respectively by MRI technique.Conclusion:It is important to use MRI technique in diagnosis and differential diagnosis of the pontocerebellar tumour.