听神经瘤的MRI诊断

MRI Diagnosis of Acoustic Neuroma

本文分析手术和病理证实76例78个听神经瘤的MRI表现,其中2例为内听道内微小听神经瘤,11例作静脉注射Gd-DTPA后MRI成象。下列特征有助于听神经瘤诊断:(1)肿瘤以第Ⅶ、Ⅷ神经束为中心生长,病侧Ⅶ、Ⅷ神经束明显增粗,与肿瘤无明确分界;(2)T_1加权图象肿瘤呈低信号或低等混合信号,T_2加权图象呈高信号或高等混合信号。静脉注射Gd-DTPA对诊断微小听神经瘤常甚有效。

The MRI findings of 78 acoustic neuromas verified by operation and pathology from 76 cases, in which 2 tumors were intracanalicular, were analyzed. 11 cases were imaged after intravenous Gd-DTPA administration. The following features are helpful in the diagnosis of acoustic neuroma: (1) The tumors grow round the affected nerves and are poorly demarcated from the affected nerves. The thickening of the affected nerves is usually visible. (2) The tumors are usually hypointensive of hypo-iso-intensive on T1 weighted images and are hyperin-tensive or hyper-iso-intensive on T2 weighted images. After Gd-DTPA administration the MRI is sensitive to detection of small acoustic neuroma.