脑梗死后MR弥散加权成像上信号强度变化的随访观察  

Signal Intensity Changes on Diffusion-weighted MRI after Cerebral Infarction: A Follow-up Observation

作　　者：周根泉[1] 张悦萍[1] 汪守中[1] 李建奇[1] 胡运胜[1] 诸慧铭[1] 陈丽萍[1] 王为珍[2] 

机构地区：[1]上海市第一人民医院放射科,200080 [2]上海市第一人民医院神经内科,200080

出　　处：《临床放射学杂志》2002年第12期929-932,共4页Journal of Clinical Radiology

基　　金：上海市卫生局青年课题基金资助项目 (No .984Y1)

摘　　要：目的　随访观察脑梗死后在MR弥散加权成像 (DWI)上信号强度的变化。资料与方法　对 81例确诊为脑梗死的患者在梗死后不同时间行常规MRI和DWI。 81例均有明确的发病时间、脑梗死的典型症状、体征 ,并持续48h以上。其中 8例分别在不同时间作了 2次MR扫描 ,3例在 2个不同的解剖部位各出现一个梗死灶。因此 ,共有92个病灶用于分析。以邻近或对侧正常脑组织的MR信号强度作对照 ,观察脑梗死后不同时间在DWI上信号强度的变化。结果　发病后 3天内作MRI检查的 43例患者的 47个病灶 ,在DWI上均显示异常高信号 ;在发病后 4～ 7天内作MRI检查的 1 7例患者的 1 9个病灶中 ,1 8个病灶在DWI上显示异常高信号 ,阳性率为 94.7% ;在发病后 8～1 4天和 1 5～ 2 0天内检查的患者中 ,DWI的阳性率分别为 66 .7%和 2 8.6 % ;梗死后 2 0天以后检查的患者 ,在DWI上均未显示异常高信号。结论　脑梗死后 3天内 ,在DWI上均表现为异常高信号 ,在发病后 4～ 7天内 ,DWI的阳性率为 94.7% ,以后逐渐下降。大约在 3周后 。Objective To observe the signal intensity changes of the cerebral infarcted foci on diffusion weighted imaging (DWI) after the onset of stroke. Materials and Methods Both conventional MRI and DWI were performed in 81 patients at different time after cerebral infarction. All the patients had a clear onset of illness, and clinically showed typical symptoms and signs of cerebral infarction, which persisted over 48 hours. Two sessions of MR scanning at different time were carried out in 8 patients, and 3 patients showed two separate infarction foci at two anatomical sites. A total of 92 infarction lesions could be used for analysis. The signal intensity of the adjacent or contralateral normal brain was used for comparison, and the changing in signal intensity of the infracted lesions on DWI was observed.Results On DWI, abnormal high signal intensity was demonstrated in all of 47 foci (in 43 cases) and in 18 (94.7%) of 19 foci (in 17 cases) showed on MRI which was performed at 3 days and at 4～7 days after the onset, respectively. The positive rate obtained with DWI at 8～14, 15～20 and after 20 days was 66.7%, 28.6% and 0%, respectively.Conclusion In patients of cerebral infarction, abnormal high signal intensity is demonstrated on all DWI obtained within 3 days after the onset, which remains as high as 94.7% at 4～7 days, then the displaying rate of this sign decreases until 20 days when the abnormal high signal intensity is no longer seen.

关 键 词：信号强度 DWI 脑梗死 中风 磁共振成像 磁共振弥散加权成像 

分 类 号：R445.2[医药卫生—影像医学与核医学]