三叉神经瘤的影像学诊断

Imaging diagnosis of trigeminal neuroma

目的 :提高三叉神经瘤的影像诊断和鉴别诊断水平。方法 :经手术病理证实的 17例三叉神经瘤 ,分析其MRI、CT及DSA表现。结果 :肿瘤表现①中颅窝 6例 ,肿瘤瘤体小 ,多为实性无囊变。后颅窝 4例 ,瘤体大有囊变、坏死。跨颅窝 3例 ,典型的哑铃状 ;②MRIT1WI肿瘤呈稍低信号或低、等混杂信号 ,T2 WI呈高信号及高、等混合信号 ,CT平扫为低或混合密度。增强呈均匀性或环状、结节状强化。DSA示肿瘤多血供 ,斑点状染色 ;③三叉神经根增粗及功能异常 ,常伴岩骨、颅底骨质吸收、破坏。结论 :MRI、CT是三叉神经瘤理想的影像学检查方法 ,MRI优于CT ,定性困难者 ,结合DSA易做出诊断。

Objective:To improve imaging diagnosis and differential dignostic level of trigeminal neuroma.Methods:The imaging appearances of 17 cases with trigemial neuromas verified by operation and pathology were analyzed.Results:The imaging appearances of trigerminal neuroma were as follows:①Of 17 cases,6 cases located in middle cranial fossa,the lesions showed small in size and no capsular.In 4 cases tumors in posterior cranial fossa,were large in size with capsular or necrosis.3 cases with typical dumb-bell like in shape grew across middle and posterior cranial fossa;②The tumors were of slightly hypo or iso-hypo signal intensity on T 1WI and hyper or iso-hyper signal intensity on T 2WI.The hypo or mixed density were showed by CT.On contrast scan,the tumors were enhanced homogeneously,inhomogeneously,circularly or nodularly.Hypervascular and dot-stained tumors were found on DSA; ③The roots of trigeminal nerves thickening with dysfunction and erosion of petrous bone were found in most cases.Conclusion:Both MRI and CT are ideal imaging method for the diagnosis of trigeminal neuroma but MRI is superior to CT.When the nature of the lesion is difficult to determine,dignosis is easy by combining with DSA.