A 70 year old hypeensive male presents complaining of a brief episode of slurred speech and left sided weakness previous evening. He gives a history of two transient episodes of sudden loss of vision in his right eye last month. His Neurological examination is normal now. What is most appropriate next diagnostic test?

Symptoms of contralateral transient ischemic attacks and ipsilateral transient monocular blindness(Amaurosis fugax) suggest extracranial internal carotid aery disease and have high likelihood of developing strokes The Appropriate next step to confirm the suspicion of carotid stenosis is Doppler ultrasound of carotid vessels to look for atheromatous plaques and stenosis. Carotid Doppler showing irregular plaque(red arrow) in proximal ICA causing narrowing of lumen. Angiography is invasive,expensive and carries a risk of causing stroke