Any patient who has suffered upper or lower extremity weakness or diminished sensation ie numbness, speech difficulty, visual field deficits symptoms whether permanent (stroke) or reversible (TIA) should undergo carotid duplex ultrasound ( US) to determine if there is significant blockage. Duplex US is a non invasive study that is performed without giving any dye or exposing the patient to irradiation.
Additionally a CT angiogram or MRI of the brain is essential to confirm the location, severity and structure of the blockage determine which region and extent of brain is involved.
A cardiac cause should also be ruled out clots can originate from the heart and travel to the brain due to arrhythmias or after a heart attack.
Carotid blockage may exist as previously mentioned without symptoms. So who should be screened by duplex US; the following
a) Patients with known coronary artery, peripheral artery disease, aortic aneurysms
b) Hearing a carotid bruit on physical exam
c) Age 60 and above with longstanding atherosclerosis risk factors ( smoking, hypertension, hyperlipidemia, diabetes, or thrombophilic disorders.