The Significance of Carotid Artery Longitudinal Wall Motion: Insights from Block-Matching Ultrasound Analysis

Abstract

Cardiovascular disease remains the leading cause of morbidity and mortality worldwide, primarily driven by atherosclerosis. Early identification of vascular dysfunction is therefore clinically important. This thesis investigates carotid artery longitudinal wall motion (CALM) as a functional biomarker of arterial mechanical behavior, using B-mode ultrasound imaging combined with a custom MATLAB speckle-tracking framework. Cine loops from fourteen subjects with carotid atherosclerotic plaques were processed using a multiple kernel block-matching algorithm to extract longitudinal displacement, velocity, and diameter waveforms. Across all subjects, CALM exhibited the characteristic multiphasic pattern of alternating antegrade and retrograde motion. However, amplitudes were consistently reduced compared with reference values for healthy arteries. Peak antegrade displacement measured 0.03 ± 0.01 mm and peak retrograde −0.05 ± 0.02 mm, substantially below the typical physiological range (0.2–1.0 mm). Corresponding peak velocities were also modest (0.42 ± 0.18 mm/s) and diameter pulsation was attenuated (0.29 ± 0.11 mm), indicating diminished distensibility and localized stiffening in plaque-affected regions. The results demonstrate that CALM quantification is feasible with standard ultrasound imaging and low-complexity computational tools, while capturing functional arterial changes not reflected in structural markers such as intima–media thickness. Overall, this work provides a reproducible processing framework and supports the potential of CALM as a sensitive indicator for early atherosclerotic disease characterization.