颅脑多发性硬化的MRI诊断

MRI diagnosis of multiple cerebral sclerosis

目的探讨颅脑多发性硬化MRI特征表现,提高对颅脑多发性硬化(MS)的影像诊断水平。方法搜集2002年2月～2008年3月间经南方医院收治的32例MS病例MRI检查资料。常规扫描T1WI、T2WI、Flair序列,26例行Gd-DTPA增强扫描;分析MS斑块分布的部位、大小、形态、MR信号及强化特点、占位征象、胼胝体改变及脑萎缩。所有数据采用描述性统计方法。结果32例MS患者中,30例MRI脑部有阳性病灶,敏感性为93.75%。全部为多发病灶,以皮层或皮层下白质、侧脑室旁、半卵圆中心、胼胝体为其好发部位。MS斑块直径大小不等,以圆形、卵圆形占大多数。双侧病灶大部分对称分布。其中"直角脱髓鞘征"20例、"白质变脏征"12例,兼具此二征者11例。T1WI表现为等、稍低或低信号。T2WI及Flair序列呈高信号。增强扫描大部分斑块无强化,强化斑块主要表现为结节状强化、环形强化。MS斑块无占位征象或轻度占位征象;矢状位胼胝体检查28例,17例信号异常,占60.71%(17/28),胼胝体萎缩5例。10例MS患者发生不同程度脑萎缩。结论MS好发于皮层或皮层下白质区、侧脑室旁、半卵圆中心及胼胝体,以圆形、卵圆形占大多数;MS斑块多发,双侧病灶大部分对称,"直角脱髓鞘征"及"白质变脏征"为MS较特异的征象;大多数MS斑块增强扫描可无强化,或出现结节状强化、环状强化;MS斑块无或有轻度占位征象;常侵犯胼胝体,表现为弥漫性、结节状、放射状信号异常及室管膜不规则形增厚,以矢状位Flair序列显示较好。

Objective To investigate the magnetic resonance imaging （MRI） feature of multiple cerebral sclerosis （MS） for better understanding and diagnosis of this disease. Methods The MRI data of 32 patients with MS were reviewed. Conventional scanning with T1WI, T2WI, Flair sequence was performed, and 26 patients underwent Gd-DTPA enhanced scanning. The MS plaques were analyzed for their locations, sizes, shapes, MR signals and enhanced features, space-occupying signs, and the related corpus callosum changes and brain atrophy. Descriptive statistical method was used for all the data. Results MRI identified MS lesions in the brain in 30 cases, with the sensitivity of 93.75%. All the MS patients had multiple lesions with predilection sites of the cortical/juxtacortical and periventricle areas, the centrum semiovale, and the corpus callosum. Most of the MS plaques were round or oval of different sizes. Bilateral lesions were almost symmetrical in distribution. Twenty patients had ＂rectangular demyelination＂ and 12 had ＂dirty white matter＂ signs, and 11 had both manifestations. The lesions were isointense, slightly hypointense or hypointense on T1WI, and hyperintense on T2WI and Flair sequences. Most of the MS plaques presented no enhancement, with occasional nodular or circular enhancement. No or slight space-occupying effect was found in the plaques. Of the 28 MS patients undergoing sagittal scanning of the corpus callosum, 17 presented with abnormal signals, with the sensitivity of 60.71% （17/28）. Five patients had corpus callosum atrophy, and 10 had brain atrophy of different degrees. Conclusion These results suggest that the corpus callosum is often compromised by the MS lesions to present diffusive, nodular, radiating signal abnormalities and irregular ependymal thickening, which can be most obvious with sagittal FLAIR imaging.