Attenuation Coefficient Parameter Estimations to Characterize Ex Vivo Carotid Plaque

A leading cause of stroke is carotid artery atherosclerosis. Attenuation coefficient (AC) parameters can evaluate carotid plaque echogenicity and visualize plaque composition for assessments of vulnerability. High-frequency radiofrequency (RF) data (fc = 40 MHz) were acquired using a stepper motor from 10 plaques removed via carotid endarterectomy. AC parameters such as Median AC were calculated using an optimum power spectral shift estimation (OPSSE) method developed in our lab. Parametric maps were created to visualize AC parameter variation throughout plaque. AC parameters were compared with surgical scores and histopathology assessments. Kendall's tau correlations compared AC parameters, whole plaque scores, and histopathology assessments. Kruskal-Wallis H and Dunn's post hoc test assessed ability of AC parameters to distinguish among tissue scores. This work demonstrates a technique for computing AC parameters that suggests correlations and discriminatory potential for surgical and histopathological markers of plaque composition and vulnerability.