Color M-Mode Ultrasound to Assess Carotid Arteries: A Feasibility Study

Abstract

Introduction: The gradual process of atherosclerosis involves both structural and functional changes that can accumulate over years and contribute to cardiovascular risk. We propose the use of color M-mode ultrasound to evaluate the distensibility of the carotid artery as a quantitative measurement of dynamic function that could evaluate age-related vascular change when considering atherosclerotic cardiovascular disease evaluation and risk. The aim of the study was to assess the feasibility of color M-mode ultrasound to evaluate age-related changes in the carotid arteries. Methods: Color M-mode ultrasound of the distal common carotid artery (CCA) with concurrent electrocardiogram tracing was performed on 62 adults (19 men and 43 women) in 3 age groups: young adult (20-44 years; n = 22), middle age (45-64 years; n = 20), and senior (≥65 years; n = 20). Color M-mode ultrasound images of the CCA were processed offline using ImageJ to quantify total, red, green, and blue (RGB) pixels in systole and diastole. The CCA distensibility was calculated by using the following equation: distensibility coefficient (DC) = (systolic − diastolic diameter)/(diastolic diameter × pulse pressure). The difference in ultrasound parameters among the 3 age groups was analyzed by one-way analysis of variance (ANOVA). Intraobserver and interobserver reliability of offline imaging processing was tested using intraclass correlation coefficient (ICC). Results: We observed a significant difference in CCA distensibility among the 3 age groups (P < .05). The interobserver reproducibility and intraobserver repeatability in performing offline image processing were excellent (ICC >0.85). Conclusion: These findings suggest that color M-mode ultrasound is feasible in evaluating changes in CCA distensibility and systolic pixel values representing CCA blood flow significantly decreased in seniors.