多发性硬化的MR扩散加权成像研究

目的：总结多发性硬化（multiple sclerosis,MS)的扩散加权成像（diffusion-weighted imaging,DWI)表现，定量研究MS病灶区水分子表观扩散系数(apparent diffusion coefficient,ADC）值、扩散各向异性指数（anisotropy index,AI)的变化规律。方法：18例218个病灶分为5组：A组为MS急性期活动性病灶9例72个病灶，B组为A组中4例治疗后随访的病例，共31个病灶，C组为缓解－复发型的缓解期静止病灶9例（115个病灶），D组取病灶对侧或邻近的正常表现白质区域(normal appearance white matter,NAWM)，共218个，E组为正常对照组18例。总结病灶在DWI与常规MRI上的表现。测量病灶及临近正常表现白质区以及正常对照组相应区的ADC、AI。结果：在DWI上，进展型MS表现为高信号（T2WI表现为水肿样高信号）。缓解－复发型的急性发作期MS表现为环形或圆形高信号病灶。缓解－复发型的缓解期病灶与白质相比表现为稍高信号。各种分型与分期的MS病灶的ADC升高，AI下降，与NAWM及正常对照组间存在明显差异（F＝26．89，P＜0．01）。AI在病程后期表现为明显下降。MS病灶在T2WI上表现为高信号。强化MS病灶的ADC值 比非强化病灶的ADC值低（t＝4．19，P＜0．01），而2组的AI值之间无显著性差异（t＝0．99，P＞0．05）。结论：DWI与常规MR相比可以提供定量的诊断信息。能够反映MS不同临床分期的病理变化。扩散定量研究在MS的诊断、鉴别诊断以及疾病预后疗效中有重要的价值。

The study of the multiple sclerosis by using MR diffusion-weighted imaging

Objective To summarize the appearances of MS lesions on DWI, and to quantitatively study the ADC and AI values in different clinical MS subgroups Methods One hundred and eighty seven lesions were studied in 18 cases of MS at different clinical stages Routine MR and DWI were performed in all cases ADC and AI were calculated in the lesions,NAWM, and normal control group Results Hyperintensity (edema like on T 2WI) was demonstrated on DWI at acute primary progressive MS lesions Hyperintense ring sign was found at acute relapse MS lesions ADC increased in all subgroups of MS Significant difference of ADC was demonstrated among MS lesions, NAWM, and normal control groups Significant decrease of AI was demonstrated at later stages Hyperintensity was found in all MS lesions on T 2WI The hyperintensity lesions on DWI had enhanced or non enhanced appearances on CE T 1WI The ADC value of enhanced MS lesions was less than that of the non enhanced lesions ( t =4 19, P <0 01), while no difference was found for AI ( t =0 99, P >0 05) Conclusion DWI could give quantitative information for different pathological changes in MS lesions of different clinical subgroups Quantitative measurement of diffusion has great potential value in the diagnosis, differential diagnosis, and the prediction of prognosis in MS