ObjectiveTo explore the relationship between the duration, MRI characters and prognosis in transient ischemic attack (TIA). Methods36 TIA cases were retrospectively analyzed according to the duration and Magnetic Resonance Imaging Diffusion Weighted Imaging(MRI-DWI). They were divided into two groups, Group A (13 cases) in which TIA continued within 1 h and Group B (23cases) in which TIA continued for 1～24 h. The patients were followed up 3 months and 12 months later. ResultsMRI abnormalities could be found with MRI-DWI in 2 cases in Group A, but 17 cases in group B(χ2=11.416,P=0.001). 1 case in Group A and 14 cases in Group B occurred cerebral infarction within a year(χ2=9.663,P=0.004). ConclusionThe longer TIA duration, the worse the prognosis.