DUPLEX CAROTID SONOGRAPHY IN DISTINGUISHING ACUTE UNILATERAL ATHEROTHROMBOTIC FROM CARDIOEMBOLIC CAROTID-ARTERY OCCLUSION

PURPOSE: To distinguish between acute complete unilateral cardioemboli c and atherothrombotic internal carotid artery (ICA) occlusion by usin g duplex carotid sonography. METHODS: We studied 11 patients with card ioembolic ICA occlusion (CE group), 32 patients with atherothrombotic ICA occlusion (AT group), and 25 patients with normal angiographic fin dings (control group). We obtained B-mode scans and measured the end-d iastolic flow velocity (EDV) in both common carotid arteries within 3 days of the onset of symptoms. Side-to-side ratios of EDV (ED ratio) w ere calculated by dividing the flow velocity on the unaffected side by that on the affected side. RESULTS: In the AT group, the proximal ICA was full, with a large area of heterogeneous and partially calcified plaque, and the EDV (10.9 +/- 6.1 cm/s) was significantly lower than t hat in the control group (20.3 +/- 6.0 cm/s). The ED ratio was greater than 1.4 in all but one patient. In three patients in the CE group, B -mode scans showed a mobile, echogenic intravascular structure in the proximal ICA. The EDV (1.8 +/- 3.4 cm/s) was significantly lower than that in the control and AT groups. The ED ratio was greater than 1.4 i n all cases. CONCLUSION: We conclude that B-mode scans and the EDV in the common carotid artery can help to distinguish between acute cardio embolic and atherothrombotic ICA occlusion.