Inclusion Criteria:  Transient ischemic attack in anterior flow area (with diffusion restriction on DWI/ADC sequences of the cerebral MRI, corresponding to recent ischemia) or clinical diagnosis of brain infarction (cerebral CT for exclusion of brain haemorrhage) Opportunity to undergo Ultra-COMPASS ultrasound measurements ≤7 days after initiation of first clinical symptoms Stenosis 30-70% of carotid arteries based on clinically performed carotid ultrasound or thickening of at least 2mm on CT/MR scan ≥18 jaar Signed informed consent  Exclusion Criteria:  Total occlusion common carotid artery or internal carotid artery Cardio-embolic nature of ischemic stroke (a.o. atrial fibrilation, valvular prothesis, endocarditis, recent myocardialinfarction) Restenosis after carotid endarterectomy Acute myocardial infarction Radiotherapy-induced carotid stenosis