Inclusion Criteria- Healthy volunteers with no previous history of cerebrovascular disease and aged over 18 years old.
- Patients with symptomatic cerebrovascular event (stroke, transient ischaemic attack or amaurosis fugax) and image confirmed carotid artery stenosis of >30%. This will include patients scheduled for carotid endarterectomy (>50% for men and >70% for women, by North American Symptomatic Carotid Endarterectomy Trial criteria) or treated conservatively with an optimal medical therapy (if patient declined surgical intervention or is outside surgical criteria for carotid endarterectomy).
Exclusion Criteria- Subjects unable to comply with the study procedures such as a severe disabling stroke.
- Inadequate temporal window for Transcranial Doppler assessment.
- Adults with incapacity.