短暂性脑缺血发作的影像学表现

目的　观察弥散成像 (DWI)、血流灌注成像 (PWI)、磁共振血管造影 (MRA)对短暂性脑缺血发作 (TIA)的诊断意义。方法　对 16例TIA患者的颈内动脉系统在发病后 1～ 6h行DWI、PWI、常规MRI及MRA检查 ,并对其中 1例于病后第 2天和第 3天复查MRI、MRA。其余 15例于病后 3～ 8d复查MRI和MRA或CT检查 1次。结果　在发病1～ 6h内行MRI检查的 16例中 ,CT及T1、T2 加权像均未见异常 ;MRA发现一侧颈内动脉闭塞者 2例 ,其前后交通动脉均开放 ;1例DWI正常而PWI显示在大脑中动脉供血区域血流量下降 ,3h后症状体征消失 ,次日MRA示颈内动脉再通 ;另 1例DWI、PWI未见异常。这 2例均在 2～ 3d后因血管再闭塞或侧支循环闭塞而出现梗死灶。DWI异常的 5例 ,PWI、MRI及MRA却未见异常 ,症状缓解后复查MRI,在DWI异常的部位发现梗死灶。 9例临床表现为TIA的患者 ,其DWI、PWI、MRI及MRA未发现异常 ,以后复查MRI或CT也未发现异常。结论　DWI、PWI及MRA对颈内动脉系统TIA的诊断和预后的估计具有重要意义

Imaging manifestation of transient cerebral ischemic attack

Objective To investigate the value of DWI,PWI and MRA in the diagnosis of transient ischemic attack (TIA).Methods The DWI,PWI,routine MRI and MRA examination were carried out in 16 patients with TIA of carotid artery system in 1～6 hours after onset of the disease.Of them,One patient received second and third MRI and MRA examination on the second and the third day respectively after onset of the disease while the other 15 TIA patients received MRI and MRA or CT re examination 3～8 days after onset.Results CT or T 1? T 2 abnormality was not found in these 16 TIA patients 1～6 hours after onset of the disease.Two cases were found to have internal crotid artery block in MRA.The anterior communication artery and posterior communication artery of both of them opened and in one of them,DWI was normal but PWI showed that the cerebral blood flow(CBF) decreased in the area supplied by the middle cerebral artery.His symptoms and signs disappeared in three hours after onset,and MRA showed that his occluded internal carotid artery reopened on second day.DWI and PWI of the another patient were normal.Both of these two cases were found to have internal carotid artery or collateral circulation block and cerebral infarction by MRA and MRI re examination 2～3 days later.Five TIA patients had abnormal DWI,but their PWI,MRI and MRA were normal.Cerebral infarction was found in the abnormal DWI area by re examination after symptoms were relieved.Nine TIA patients had normal DWI,PWI,MRI,MRA and all of them had normal MRI or CT by re examination.Conclution DWI,PWI and MRA have important significance in diagnosis and prognosis of TIA of carotid artery system.