Do ultrasonographic surface characteristics of carotid plaque correlate with intraoperative findings?

Purpose: The correlation between carotid plaque morphology identified by preoperative ultrasound and operative findings remains controversial. Here, we compare carotid plaque surface characteristics by B-mode imaging with intraoperative analysis of each specimen. Methods: B-mode images and operative findings of 76 consecutive carotid endarterectomy specimens were analyzed using a blinded protocol. Ultrasonographic features were classified into three groups: homogeneous noncalcified plaques (Group 1); heterogeneous plaques (Group 2); and diffusely calcified plaques (Group 3). In each group, the presence of ulceration, thrombus, or both was carefully noted. The macroscopic features of each plaque were recorded from review of intraoperative photographs. The accuracy of B-mode ultrasound was determined in comparison with the macroscopic appearance of each specimen. Results: The 10 group I lesions had no ulceration or thrombus by either B-mode imaging or macroscopic examination. There were 35 lesions in Group 2; three ulcers and four thrombi were detected by ultrasound. An additional eight ulcers and one thrombus were found intraoperatively. The sensitivity and specificity of detecting ulceration or thrombus in patients in Group 2 was 43.8% and 100%, respectively, with a positive predictive value of 100%, Group 3 contained 31 diffusely calcified plaques, which precluded any true surface characterization of the plaques by ultrasound. Conclusions: Although B-mode imaging is useful in determining the gross morphologic appearance of carotid plaque, its use in detecting ulceration or thrombus is limited by the amount of calcification present.