Ultrasonic evaluation of the site of carotid axis occlusion in patients with acute cardioembolic stroke.

Abstract

We performed the present study to determine whether the site of cardioembolic occlusion in the carotid axis could be identified by end-diastolic velocity measurements of the common carotid arteries. Using duplex carotid ultrasonography, we measured the flow velocity in the common carotid arteries and calculated the side-to-side ratios of the end-diastolic velocity (ED ratio; the end-diastolic velocity of the nonaffected side divided by that of the affected side) in 46 patients with acute cardioembolic stroke. The velocity on the faster side was divided by the slower velocity to obtain the normal values of ED ratio in 30 controls. The ED ratios were compared with the angiographic findings, in which unilateral intracranial internal carotid artery occlusion was present in 20 patients (IC group), occlusion of the horizontal segment of the middle cerebral artery was present in 16 patients (M1 group), and branch occlusion of the middle cerebral artery was present in 10 patients (MBr group). The ED ratios of the control group were less than 1.3; those of the MBr group generally less than 1.3; the IC group greater than 4.0, except in two patients with severe cerebral edema; and those of the M1 group between 1.3 and 4.0. Therefore, the IC group was easily distinguished from the other groups by an ED ratio greater than or equal to 4.0, with an accuracy of 97%, and the M1 group by an ED ratio greater than or equal to 1.3 and less than 4.0, with an accuracy of 93%. We found the ED ratio useful to identify internal carotid artery and middle cerebral artery occlusion in patients with cardioembolic stroke unless severe cerebral edema was present.