单方向背景抑制 MR 扩散加权成像与三维短时反转恢复快速自旋回波成像增强扫描显示臂丛神经的对比研究

摘要

目的：比较单方向背景抑制扩散加权成像（ DWIBS）与三维短时反转恢复快速自旋回波成像（3D STIR SPACE）增强扫描2种方法显示臂丛神经的优势及不足。方法20名正常志愿者行臂丛神经单方向DWIBS与3D STIR SPACE增强扫描，原始图像经冠状面MIP重组，所得图像质量分别从臂丛神经各部分显示情况及背景抑制情况（ I～IV分评分法）2方面进行评价。双侧臂丛神经锁骨上部分（脊神经C5～T1）20名受试者双侧共计200支，锁骨下部分20名受试者双侧共计40支。2种成像方法对臂丛神经的显示情况进行配对资料χ2检验；对背景抑制情况评分结果采用非参数Wilcoxon符号秩和检验进行比较。结果单方向DWIBS与3D STIR SPACE增强扫描2种方法中，双侧臂丛神经锁骨上部分（C5～T1）、锁骨下部分的显示率分别是84％（167/200）、33％（13/40）与99％（198/200）、95％（38/40），2种方法间比较差异均具有统计学意义（χ2值分别为28.18、31.15，P值均＜0.01）；单方向DWIBS扫描背景抑制评分Ⅰ～Ⅳ分的分别为0、0、4、16名，3D STIR SPACE增强扫描背景抑制评分Ⅰ～Ⅳ分的分别为15、4、1、0名，2者间差异具有统计学意义（Z＝3.96，P＜0.01），3D STIR SPACE增强扫描背景抑制评分明显优于单方向DWIBS。结论3D STIR SPACE增强扫描较单方向DWIBS可获得更好的臂丛神经图像质量，能显示臂丛神经全部走行。%Objective To evaluate two different MRI techniques , enhanced 3D STIR SPACE and unidirectionally-encoded DWIBS MR Neurography in visualizing the brachial plexus.Methods Twenty healthy volunteers underwent MR scanning by the procedures of unidirectionally -encoded DWIBS and enhanced 3D STIR SPACE sequence of the brachial plexus.Original images were reconstructed with coronal maximum intensity projection ( MIP ).The image quality was assessed by comparing the visualization of various parts of the brachial plexus and the suppression ratio of image background.The degree of visualization was compared via χ2-test of paired data , and comparison of background suppression scores was performed using a nonparametric Wilcoxon signed rank sum test.Results The successful rate of visualizing the brachial plexus supraclavicular section ( C5-T1 ) was 84% ( 167/200 ) and 99% ( 198/200 ) , respectively, for the DWIBS and enhanced 3D STIR SPACE, and the rate for the infraclavicular section was 33%( 13/40 ) and 95% ( 38/40 ).The differences between these two techniques were statistically significant (χ2 value was 28.18 and 31.15 respectively, P <0.01).In all images, the scores of grade (Ⅰ-Ⅳ) of background suppression were 0, 0, 4 and 16 for unidirectionally-encoded DWIBS, respectively;while they were 15, 4, 1 and 0 for enhanced 3D STIR SPACE.There was significant difference between the two techniques ( Z =3.96,P <0.01).Conclusions High-quality MR neurography of the brachial plexus can be obtained using the enhanced 3D STIR SPACE sequence.It offers a complete anatomical coverage of the brachial plexus , and thus demonstrates a better capacity in depicting the anatomy of brachial plexus as compared with the unidirectionally-encoded DWIBS.