The prevalence and clinical significance of ischemic lesions on diffusion-weighted image in patients with transient ischemic attack

Abstract

Background and Purpose: We investigated the prevalence and clinical significance of ischemic lesions on diffusion-weighted images (DWI) in patients with transient ischemic attack (TIA).Methods: The association between clinical data and the DWI findings on admission and the 1–3 hospital days was examined in 166 consecutive patients with TIA.Results: 1) Fifty-five patients (33.1%) had positive ischemic lesions on the first or follow-up DWI. 2) Sixteen among them showed no lesion on the initial DWI within 24 hours of symptom onset. 3) DWI-positive lesions were not associated with the duration of symptoms and or the delay from the onset to the initial DWI. 4) In 9 among 55 DWI-positive patients, an ischemic lesion disappeared on the follow-up T2 weighted image. 5) Patients with a single ischemic lesion were more common in the supratentorial penetrating artery area. Whereas in patients with multiple ischemic lesions, they were more common in the area of the cortical branch of the middle cerebral artery. 6) DWI-positive patients were more likely to result from a cardio-embolic mechanism, whereas DWI-negative patients were more likely to result from a lacunar mechanism.Conclusion: DWI-positive patients accounted for 1/3 of all TIA patients. Within 24 hours following symptom onset, some patients showed no lesion on the initial DWI, but a positive lesion on the follow-up DWI. In our study, there was no association between a DWI-positive lesion and the duration of the symptoms. DWI-positive lesions did not always develop into cerebral infarction.