ECHOLUCENT REGIONS IN CAROTID PLAQUE - PRELIMINARY-ANALYSIS COMPARING3-DIMENSIONAL HISTOLOGIC RECONSTRUCTIONS TO SONOGRAPHIC FINDINGS

This study compares sonographic and histologic findings within defined spatial regions in carotid artery plaque, using computer generated th ree-dimensional reconstructions. Twenty-four patients (14 asymptomatic , 10 symptomatic) with angiographically documented 70% to 99% carotid artery stenosis were examined with ultrasonic B-mode imaging prior to endarterectomy. Using a standardized protocol for instrument set-up an d scanning technique, echolucent regions in the plaque were identified . After endarterectomy, each plaque was sectioned at 0.5 to 1.0 millim eter increments throughout its length. Sites containing intraplaque he morrhage, cholesterol clefts, foam cells, necrotic cores, dense calcif ication and speckled calcification were identified. These areas were o utlined on a template, digitized and imported into a computer program that created three-dimensional reconstructions of the histologic findi ngs. Each carotid plaque was divided into quadrants for analysis: (1) lateral wall proximal to the common carotid bifurcation (flow divider) ; (2) medial wall proximal to the flow divider; (3) lateral wall dista l to the dow divider; and (4) medial wall distal to the flow divider. The odds of finding intraplaque hemorrhage, foam cells, necrotic cores and speckled calcification were significantly higher in quadrants wit h an echolucent region identified by ultrasonography (odds ratio (95% confidence interval) for intraplaque hemorrhage = 3.5 (1.4-8.6); foam cells = 4.0 (1.6-9.9); necrotic cores = 3.2 (1.2-8.4); speckled calcif ication = 4.0 (1.6-9.8). This preliminary analysis demonstrates the po tential of these newly developed techniques for comparing ultrasonic i maging to histology.