磁共振灌注成像证实的无临床体征对应的脑血流分布不均征象与临床

The Features of MRI-PWI Proved Cerebral Blood Flow Uneven Distribution without Corresponding Clinical Signs

目的分析由磁共振灌注成像（magnetic resonance imaging—perfusion weighted imaging，MPI-PWI）证实的无临床体征对应的脑血流分布不均征象的特点，探讨其发生机制。方法2008年1月至2009年1月间顺序在我院放射科行头颅磁共振（magnetic resonance，MR）动态增强灌注成像的患者100例，其中7例（7％）患者存在无临床体征对应的脑血流分布不均征象。对所有入组患者自检查之日起终身随访（7d到14个月不等）。对这些患者的临床症状体征、磁共振血管成像（magnetic resonance angiography，MRA）显示异常的血管区域及灌注成像（perfusion weighted imaging，PWI）显示血流不均的部位进行分析总结。结果无相应临床体征对应的7例患者共13个PWI脑血流分布不均匀区。PWI显示符合Ⅱ期改变的6个（4例），符合Ⅲ期改变的6个（5例），符合Ⅳ期改变的1个。仅有1个区域与临床症状及MRA表现相符，2个区域与临床表现相符但与MRA表现不相符，4个区域与临床症状不相符但与MRA表现相符，6个区域与临床症状及MRA表现均不相符。结论灌注异常在非缺血性卒中诊断病例中存在部分脑血流不均，此类型脑血流不均与临床症状及MRA显示的血管异常无明确对应关系，以PWI与扩散加权像（diffusion weighted imaging，DWI）不匹配区的溶栓时间窗可能需要结合患者前期的PWL血流分布情况综合判断。

Objective To analyze the characteristics and its possible mechanism on MRI-PWI proved cerebral blood flow uneven distribution without corresponding clinical signs. Methods There were seven cases of one hundred which performed the examination between January 2008 and January 2009 with cerebral blood flow uneven distribution without corresponding clinical signs. All patients underwent lifelong follow-up（varied from 7 days to 14 months）. Retrospectively analyzed the clinical manifestation, MRA and PWI features of the 7 cases. Results There were 13 cerebral blood flow uneven distribution regions in 7 cases. One region was consistent with both clinical symptom and MRA features. Two regions were consistent with clinical symptom but weren＇t consistent with MRA feature. Four regions were consistent with MRA feature but weren＇t consistent with clinical symptom. Six regions were consistent with neither clinical symptom nor MRA feature. Six regions accorded with PWI grade Ⅱ, Six regions accorded with PWI grade Ⅲ, one region accorded with PWI grade Ⅳ. Conclusion PWI proved cerebral blood flow uneven distribution not only existed in the ischemic ccrebrovaseular attack patients. Brain blood flow uneven distribution of this type had no definite correlation with MRA abnormal and clinical symptoms. PWI/DWI mismatch should combine with the distribution of cerebral blood flow before to assess the patient＇s condition.