Reproducibility Study of Transcranial Doppler Microembolic Signals Detection in the Middle Cerebral Artery

Hardening of the neck vessels (carotid arteries) caused by fatty deposits called 'plaques' is a common cause of strokes. Over time plaques can burst or may lead to a severe narrowing (stenosis) of the neck artery. When plaques burst, small clots or fatty particles (called microemboli) break off, block brain vessels and lead to a stroke. Researchers have an incomplete understanding of the processes that cause hardening of the arteries, development of small clots and are unable to predict who will have a stroke. At present, the only ultrasound scan that evaluates circulation in the head and detects these small clots is called the Transcranial Doppler ultrasound. The aim of the study is to test this simple ultrasound technique to see if it can detect signals that may correspond to these small clots or fatty particles. The other objective is to see how repeatable the ultrasound technique is. This may help to identify patients with hardened neck arteries who are at higher risk of a recurrent stroke. This could also potentially improve patients selection to a targeted surgical or future novel pharmacological therapy.