功能磁共振成像在超急性脑梗死诊断中的应用

Functional MRI in evaluation of hyperacute cerebral infarction

目的 探讨功能磁共振成像在脑梗死超急性期的诊断价值。方法 采用GESigna 1.5T超导MR系统 ,对 2 9例被高度怀疑急性脑梗死且发病 6h以内的病人分别行弥散加权成像 (DWI) ,灌注成像 (PWI) ,氢质子磁共振波谱分析 (1H MRS)及常规MRIT1 W ,T2 W ,PD W检查。经工作站Functool软件包分析处理获得量值。结果 4例在临床和影像学随访后排除了脑梗死。 2 5例超急性脑梗死的fMRI检查结果为 :DWI ,PWI和常规MRI的敏感性分别为 10 0 % ,88%和 8% ;特异性均为 10 0 %。 3例经1H MRS检查结果为N 乙酰天门冬氨酸 (NAA)下降 ,含碱代谢物 (Cho)和肌酸 /磷酸肌酸 (Cr)无明显变化 ,出现乳酸 (Lac)峰 ,符合超急性期脑梗死的代谢特征。结论 功能磁共振成像在超急性脑梗死诊断方面优于常规MRI。

Objective To evaluate the functional MRI in hyperacute cerebral infartion. Materials and Methods 29 patients (19 male and 10 female, mean age 65 years old) with acute stroke symptoms underwent functional MRI examination within 6 hours of onset of symptoms. Conventional MRI (T1 weighted and T2 weighted imaging), Diffusion weighted Images (DWI) and Perfusion weighted Images (PWI) based on echoplanar sequence were performed. Magnetic Resonance Spectroscopy ( 1H MRS) was performed in 3. Results Comparing with the following clinical and imaging examinations, in 4 patients stroke was ruled out because of absence of evidence on both clinical and imaging data. In 25 patients with diagnosis of hyperacute cerebral infarction, the sensitivity of DWI, PWI, and conventional MRI was 100%, 88%, 8%, respectively, the specificity each was 100%. 3 cases of 1H MRS study showed decreased N acetylaspartate, detection of lactate peak and no obvious changes in creatine and choline. Conclusion Different findings of hyperacute cerebral infarction are depicted in functional MRI before the display of infarcted focus in conventional MRI. These techniques can improve the diagnosis of hyperacute cerbral infarct and as guide line in treaments. (Shanghai Med J, 2000,23∶531 534)