磁共振弥散加权像对早期脑梗塞的诊断价值

Early detection of human brain infarction by using diffusion weighted imaging

目的旨在分析磁共振弥散加权像对早期脑梗塞诊断的临床价值。方法２４例脑梗塞病人经磁共振成像常规程序和弥散加权程序检查，弥散加权像采用稳态自由进动程序，每层需时５７秒，弥散加权梯度为２３ｍＴ。对同一层面的所有磁共振像进行了比较，重点分析信号强度和病灶大小。数据经统计学分析。结果在超急性脑梗塞弥散加权像可显示Ｔ２加权像不能显示的病灶，在Ｔ２加权像可显示的病变中，弥散加权像可更清楚更全面地显示病灶。在亚急性期，弥散加权像的病灶有可能会呈相对等信号。本组结果略不同以往的动物实验。结论弥散加权像能非常可靠地显示急性脑梗塞。

Objective To evaluate the clinical utility of diffusion weighted steady state free precession (SSFP) sequence to detect early human brain infarction. Methods Twenty four patients were examined on a 1.5 T scanner. A diffusion weighted SSFP sequence was used. The scan time per slice was 57 seconds. The diffusion gradient strength was 23 mT. Same slices of diffusion weighted imagings and T2WIs were compared. Special attention was given to the presence of any abnormal signal intensity changes and lesion sizes. The data of the lesion size were statistically analyzed by using a linear regression method. Results In the superacute stage of brain infarction, either the infarcts were seen only with diffusion weighted imaging, or if they could be detected with T2WI, they would be seen better with diffusion weighted imaging. In subacute stage of brain infarction, relative isointensity was possibly shown on diffusion weighted imaging in a few patients. The results of this study differ slightly from the T2WI findings in a previous study of animal stroke models. Conclusion It is suggested that diffusion SSFP sequence is more sensitive and accurate to delineate acute ischemic lesion in human brain than conventional T2 weighted imaging.