Preoperative evaluation of extracranial carotid artery stenosis by ultrasonography.

Ultrasonography was applied to 24 carotid arteries in 22 patients prior to carotid endarterectomy (CEA) . The relationships between the histology of the plaque removed by CEA, especially the presence or absence of plaque hemorrhage (PH) and the echogenicity in B-mode imaging, and between clinical symptoms and turbulent flow (TF) around the plaque revealed by color flow imaging, were examined. The echogenicity of the plaque was divided into 3 grade based on comparison with that of the intimal layer: Low, in which echogenicity was hypoechoic relative to the intimal layer (5 plaques), Iso, in which echogenicity was the same as that of the intimal layer (6 plaques), High, in which echogenicity was hyperechoic relative to the intimal layer (13 plaques) . PH was found in 7 of the 24 plaques. All 5 of the hypoechoic plaques showed PH, whereas none of the 13 hyperechoic plaques didso. TF was detected in 11 of the 24 carotid arteries. Clinical symptoms occurred in 7 of the 11 patients with TF and 3 of those without TF. In conclusion, we have shown that this technique is capable of predicting the occurrence of PH due to its echogenicity in B-mode imaging. We also suggest that TF may play a role in the production of clinical symptoms.