磁共振常规和弥散加权成像技术对多发性硬化的诊断价值分析

目的比较常规磁共振（MRI）检查和弥散加权磁共振（DWI）检查技术对多发性硬化（MS）的诊断价值。方法采用美国GE公司生产的Signa 1.5T TWin Speed磁共振机对58例经临床与实验室检查明确的MS病例（男34例、女24例，平均年龄35．95岁），例行T1FLAIR、T2加权扫描（T2W1）及弥散加权成（DWI）像检查。将3种序列所见进行比较，同时使用软件进行DWI的弥散系数（ADC）值及影像分析。结果（1）MS，病灶在MRI扫描中，T2WI像共发现病灶798个，T1FLAIR检见病灶673个，T1FLAIR显示的病灶数为T2WI的84％。采用DWI检查，可见病灶537个，检见病灶数为T2WI的67％。（2）T1FLAIR所检MS病灶的信号多为低或略低信号，T2WI的病灶显示为高信号，DWI在急性期病灶显示为略高信号影，在慢性期可表现为等信号或低信号。（3）MS急性期病灶平均ADC值与急性脑梗死相比无显著性差异（P〉0.05）。亚急性和慢性期平均A13（2值（0.00105）高于脑缺血的ADC值（0.000495）（P〈0.001），但低于脑肿瘤的ADC值（0.00174）（P〈0.05）。结论常规磁共振的阳性检出率T2WI优于T1WI；DWI可以明确判定脑内白质区的MS病灶是否急性期，同时应用DWI、ADC图检查对判别病灶的性质，尤其对脑缺血性或肿瘤性病灶有较大帮助，是诊断MS等脱髓鞘疾病的有效影像学方法。

Analysis of the Diagnostic Efficacy of Routine MRI and Diffusion-Weighted Imaging of Multiple Sclerosis

Objective To compare the efficacy of routine magnetic resonance imaging(MRI) to that of diffusion-weighted imaging(DWI) in the diagnosis of multiple sclerosis(MS).Methods(1)Device: Signa 1.5T Twin Speed MRI scanner from General Electric,USA;(2)Cases: 58 patients with multiple sclerosis confirmed by clinical manifestation and laboratory exam,including 34 males and 24 females(mean age: 35.95),were examined by MRI with T_1 FLAIR,T_2-weighted imaging(T_2WI) and diffusion-weighted imaging(DWI).The findings by each of the sequences were compared and apparent diffusion coefficient (ADC) values were measured and radiologically analyzed with the specific software.Results(1)A total of 798 lesions were detected using T_2-weighted imaging(T_2 WI),including 406 in periventricular region,340 in centrum ovale,2 in corpus callosum,19 in brain stem and 9 in cerebellum.While 673 lesions were found with T_1 FLAIR,including 363 in periventricular region,263 in centrum ovale,2 in corpus callosum,16 in brain stem and 7 in cerebellum.With DWI,the total lesions detected were 537,including 290 in periventricular region,226 in centrum ovale,2 in corpus callosum,13 in brain stem and 6 in cerebellum.In sum,the lesions detected by T_1 FLAIR was 84% of those detected by T_2WI and 67% of those by T_2WI.(2)The MRI signal intensity of lesions detected appeared to be low or mildly low in T_1 FLAIR and high in T_2WI,while in DWI it tended to be mildly high in acute phase and equal or low in chronic phase.(3)There was no significant difference between the ADC values measured in the acute MS lesions and in the acute cerebral ischemic focuses(P>0.05).In contrast,the mean ADC values in subacute and chronic MS lesions(0.001 05) was significantly higher than that in the ischemic ones(0.000 495,P<0.001) but lower than that in brain tumors(0.001 74,P<0.05).Conclusion The comparison of the findings by routine MRI and diffusion-weighted imaging(DWI) suggested that the detectability by T_2WI is greater than T_1WI,and that DWI is helpful in determining whether the MS lesions are acute or not.The combined application of DWI sequence and ADC map is valuable in the differentiation of MS lesions from ischemic and tumorous focuses,thus serves as an effective radiological approach to the diagnosis of MS and other demyelization disorders.Meanwhile, it is a useful guidance to treatments.