[Ultrasonic study of the internal carotid artery]

Investigation of the internal carotid arteries by ultrasound has revolutionized the prescription of complementary examinations in ischemic cerebral accidents. There are four techniques: 1) continuous Doppler, 2) CT scan with classical Doppler 3) CT scan with colour Doppler and 4) transcranial Doppler. The complementary of these investigations makes it possible to obtain hemodynamic and morphological information on the internal carotid artery from its cervical origin to its intracranial terminal. Reliable diagnosis of atherosclerotic carotid stenoses and occlusions has considerably reduced the need for angiography. Intracranial circulation can be studied by transcranial Doppler. This technique allows evaluation of the hemodynamic influence of extracranial carotid stenoses and occlusions, and diagnosis of hemodynamic stenoses in the intracranial internal carotid artery. Assessment of the thickness of the intima plus tunica media of the primary carotid artery by CT scan appears to be a sensitive marker of cerebral and coronary ischemic risk.