对头颅轴位薄层CT扫描内听道形态的再认识

Further Recognize the Morphology of Internal Auditory Meatus on Cranial Axial CT Scan with Thin Lamina

目的 加深对内听道 (IAM)轴位薄层CT形态的认识 ,以提高听神经瘤的诊断水平。方法 复习 37例经病理证实的桥小脑角区肿瘤CT和 /或MRI资料。观察 41例无内听道病变的轴位薄层 (≤ 2mm)CT内听道的连续层面图像。 1具颅骨标本作验证。结果 薄层CT可显示轻微的内听道骨壁破坏。轴位薄层 (2mm)CT两个层面上可显示内听道。上部层面外半规管显示清楚 ,内听道多呈底尖口宽的喇叭形 ;其下部层面内听道几乎为平行状 ,其底部呈圆弧形。结论 CT观察内听道轻微骨质破坏必须使用连续薄层扫描并注意窗口技术。

Objective To further recognize morphology of the internal auditory meatus (IAM) on cranial axial CT scan with thin lamina (≤2mm) in order to improve the diagnosis of the acoustic nemoma. Methods The CT and /or MRI data of 37 patients with tumors at cerebellopontine angle proved pathologically were reviewed.The shapes and bony walls of IAM without diseases in 41 persons on axial CT scan were analyzed. One cranial bony specimen was used to verify. Results The small bony destruction of IAM only can be found on CT scan with thin lamina. The trumpet shape IAM were showed at the level of external semicircular canal on axial CT scanning mostly, while the parallel like IAM were all seen at the lower layer. Conclusion It must be used the sequential thin lamina CT scan to show the small bony destruction of IAM and the window technology is very important too. It may be the reason of the IAM with trumpet shape at the layer of external semicircular canal on thin lamina axial CT scan that the scan level does not parallel to the IAM.