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Doppler Study of the Left Common Carotid Artery With Preocclusive Stenosis

Preocclusive stenosis of the common carotid artery is a rare and potentially life-threatening entity, and the early recognition of associated internal and external carotid artery patency is important for the management plan. The patient in this case report was sent for a thyroid ultrasound for complaints of neck pain, voice change, and dysphagia, and a preocclusive stenosis of the left common carotid artery was found. Multiple collateral pathways had developed to supply blood flow to the left internal carotid artery, and there was retrograde flow in the external carotid artery and antegrade flow in the internal carotid artery. Collaterals from the left thyrocervical trunk were supplying the superior thyroid artery which supplied the external carotid artery and finally the internal carotid artery through the carotid bulb. Doppler ultrasound is valuable in the identification of preocclusive common carotid artery stenosis and mapping of collateral pathways.