New criteria for the sonographic diagnosis of a plaque ulcer in the extracranial carotid artery

Abstract

Objective: The diagnostic power of carotid sonography in detecting plaque ulcers may be inadequate when using the conventional criteria. We aimed to evaluate the usefulness of new criteria that we devised through a preliminary analysis of 50 endarterectomy cases before the present series.

Subjects and methods: Thirty carotid arteries of 30 consecutive patients who underwent endarterectomy (28 men; age range, 46-83 years) were studied. In the long- and short-axis B-mode images of carotid arteries, the concavity of the plaque surface and the surface echo intensity were carefully investigated. The conventional criteria stipulate a concavity larger than 2 × 2 mm with a well-defined back wall and flow reversal within the recess. Our new criteria specify a concavity in the plaque with the basal border echo weaker than that of the adjacent plaque surface, regardless of size. The final diagnosis was based on surgical and histologic findings.

Results: Among the 30 carotid arteries, 14 arteries had 14 ulcers at surgery. Seventeen concavities were detected by sonography, and 12 of them, including six smaller than 2 × 2 mm, were truly ulcers. Two concavities with an echo intensity of the basal border equal to or greater than that of the adjacent surface were not true ulcers. Only two of 14 ulcers were not detected by sonography. The sensitivity and specificity of the conventional criteria were 35.7% and 75.0%, respectively, and those of our new criteria were 85.7% and 81.3%, respectively.

Conclusion: Our new criteria for the sonographic diagnosis of plaque ulcer are more useful than the conventional ones.