Impact of Ultrasound Scanning Plane on Common Carotid Artery Longitudinal Wall Motion

Objective: The arterial wall not only moves in the radial direction to expand circumferentially but also moves in the axial (longitudinal) direction in a predictable bidirectional pattern during a normal cardiac cycle. While common carotid artery (CCA) longitudinal wall motion (CALM) has been described previously, there is a lack of evidence-based method standardization to align practices for human measurement. The purpose of this study was to evaluate whether different scanning planes impact CALM outcomes in healthy males and females to provide clarity on data collection strategies. Methods: Thirty-one healthy adults (16 females, 23 ± 3 y of age) underwent ultrasound scanning of the right CCA in the anterior, lateral, and posterior imaging planes. CALM was evaluated using a custom speckle-tracking algorithm and was analyzed as segmental motion outcomes (anterograde, retrograde, maximum displacement and radial-axial path length). Results: No differences in any CALM outcome were observed between imaging planes (p > 0.05), and equivalence testing indicated that retrograde CALM displacement was similar between anterior and posterior distal walls (p = 0.04). We observed no differences (p > 0.05) in CALM outcomes between the proximal (free-wall, adjacent to the internal jugular vein [IJV]) and distal wall in the posterior imaging plane. Qualitatively, it was more difficult to successfully track vascular tissue between the IJV and CCA due to the thin wall components and highly mobile wall in the radial direction. Conclusion: In the absence of clear differences between scanning planes, we recommend standardizing acquisition in the lateral plane and avoiding the IJV free-wall when evaluating CALM in humans.