 - MRI exclusion criteria: Evidence of ICH, Evidence of SAH, Signs of extensive early infarction on DWI assessed by evidence of involvement of 13 of the middle cerebral artery MCA territory. No perfusion deficit, Internal carotid artery ICA occlusion ipsilateral to stroke lesion without additional ipsilateral MCA, anterior cerebral artery ACA or posterior cerebral artery PCA occlusion. Any intracranial pathology that would interfere with the MRI assessment of acute ischemic stroke. 