Strokes can be Ischemic (80%), typically resulting from thrombosis or embolism Hemorrhagic (20%), resulting from vascular rupture (eg, subarachnoid hemorrhage, intracerebral hemorrhage) Transient stroke symptoms (typically lasting < 1 hour) without evidence of acute cerebral infarction (based on diffusion-weighted MRI) are termed a transient ischemic attack (TIA).