听神经瘤的MRI诊断
磁共振成像；听神经瘤；诊断,,],磁共振成像；听神经瘤；诊断,1资料与方法,2结果,3讨论,[参考文献]
[摘要] 目的 研究听神经瘤的MRI表现与特征。方法 通过手术病理对照，回顾分析了35例听神经瘤的MRI表现，其中微小听神经瘤为3例，行GdDTPA增强扫描为30例。结果 听神经瘤的MRI表现主要为：(1)肿瘤以内听道为中心生长，第Ⅶ、Ⅷ神经束较对侧增粗，与肿瘤主体多无明确分界，增强后可见两者相连，颇为特征；(2)肿瘤在T1加权图像上呈低信号、略低信号或低等混合信号，T2加权呈高信号或高等混合信号；(3)注射GdDTPA后肿瘤呈均匀、不均匀或环状强化；(4)肿瘤边界清晰，边缘光整；(5)绝大多数肿瘤患侧内听道前后径扩大，深径缩短；(6)微小听神经瘤的MRI表现为第Ⅶ、Ⅷ神经束正常或局部结状增粗，造影后呈结节状或点状增强。结论 MRI是检查听神经瘤的有效方法，GdDTPA对微小听神经瘤的诊断很有价值。[关键词] 磁共振成像；听神经瘤；诊断
MRI diagnosis of acoustic neuroma
Dong Jin,Liu Yicheng,Tu Qian.Department of Radiology,The First Hospital of Wuhan，Wuhan 430022,China
[Abstract] Objective To study MRI appearances and characteristics of acoustic neuromas.Methods The MRI features along with pathologic findings of 35 patients with acoustic neuroma were analysed retrospectively.There were 3 small acoustic neuromas,30 cases were GdDTPA enhanced.Results MRI appearances of acoustic neuromas were:(1)The turmor's growth round the internal auditory canal,the Ⅶ,Ⅷ nerves affected side were thickened than that of opposite side.There was no marked demarcation between the main bodies of the tumors and the affected nerves.The connection between tumors and affected nerves could be showed at contrast enhanced imaging.(2)The tumors were of hypo or isohypo intensity on T1 weighted images and hyper or isohyper intensity on T2 weighted images.(3)After GdDTPA administration the tumors were homogeneously or inhomogeneously or circularly enhanced.(4)The margins of the tumors were smooth and well delineated.(5)The affected internal auditory canal usually became shorter in depth and larger in posterioranterior diameter.(6)MRI appearances of microacoustic neuromas were that the affected Ⅶ,Ⅷ nerves were normal in size or nodularly thickened and the tumor reveaed nodular or point enhancement at contrast enhanced MRI.Conclusion MRI is an effective method in detecting acoustic neuromas.GdDTPA enhancement is very valuable in the diagnosis of microacoustic neuromas. ......
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