3D-重T_2W水成像技术显示面听神经及内耳结构的研究

Normal anatomy of inner ear and IAC on FSE 3D heavy T_2 weighted MR imaging

目的 :探讨MR薄层 3D 重T2 W水成像技术对内听道面听神经分支和迷路解剖结构的显示情况。方法 :选择 40例 (80侧 )无耳部疾病患者 ,使用GESigna 1 .5T超导MR成像仪 ,头部环形线圈或 3in(7.62cm)环形线圈 ,0 .5mm层厚 3D 重T2 WIFSE序列与常规T2 WIFSE序列对两侧耳部同时进行扫描 ,比较两者对内听道面听神经分支和迷路解剖结构的显示率 ,并作统计分析。结果 :3D 重T2 WIFSE序列与常规T2 WIFSE序列对其细微结构的显示率分别为螺旋板(98%∶0 % ,P <0 .0 1 )、前庭阶 (98%∶0 % ,P <0 .0 1 )、鼓阶 (98%∶0 % ,P <0 .0 1 )、椭圆囊 (95 %∶0 % ,P <0 .0 1 )、球囊 (95 %∶0 % ,P <0 .0 1 )、前庭嵴 (95 %∶0 % ,P <0 .0 1 )、前庭上神经 (1 0 0 %∶40 % ,P <0 .0 1 )、前庭下神经 (98%∶2 0 % ,P <0 .0 1 ) ,其差异均有显著性意义 ,而在 3个半规管、前庭、耳蜗、内听道面神经、蜗神经等结构的显示率方面差异无显著性意义 (P >0 .0 5)。结论 :薄层 3D 重T2 WFSE水成像技术在显示内听道前庭上下神经分支和迷路的螺旋板、前庭阶、鼓阶、椭圆囊、球囊等细微结构方面明显优于常规T2 WI。

Objective:To study the detectability for anatomy structures of internal auditory canal (IAC) and labyrinth in normal subjects on FSE 3D Heavy T 2WI MR imaging.Methods:MR images of 80 inner ears in 40 normal subjects were studied without related abnormalities or symptoms.All studies were performed on GE 1.5T MR scanner with a circular head coil or 3 inch circular coils,using 0.5 mm thickness on both FSE 3D Heavy T 2WI and FSE T 2WI sequences.3D reconstructed MR images of the inner ear were directly synthesized with maximum intensity projection (MIP) technique.The detection rates of the minute anatomy structures of IAC and labyrinth on FSE 3D Heavy T 2WI were compared with that on FSE T 2WI MR imaging.Results:The detection rates for the anatomy on FSE 3D Heavy T 2WI and FSE T 2WI were 95% vs 0% ( P <0.01) for saccule,95% vs 0% ( P <0.01) for vestibular crest,95% vs 0% ( P <0.01)for utricle,98% vs 0% ( P <0.01) for scala vestibuli,98% vs 0% ( P <0.01) for scala tympani,98% vs 0% ( P <0.01) for spiral lamina,100% vs 40% ( P <0.01) for nervi vestibularis superior,and 98% vs 20% ( P <0.01) for nervi vestibularis inferior,respectively.The difference of detection rates was statistically significant for these minute anatomical structures,but was not statistically significant for three semicircular ducts,vestibule,cochieae,nervi nochieae and nervi facialis ( P >0.05) between FSE 3D Heavy T 2W and FSE T 2W MR images.Conclusion:FSE 3D Heavy T 2WI MR imaging is better than FSE T 2WI MR imaging for detection the anatomical structures of internal auditory canal and labyrinth.