Carotid Wall Longitudinal Motion in Ultrasound Imaging: An Expert Consensus Review.

Motion extracted from the carotid artery wall provides unique information for vascular health evaluation. Carotid artery longitudinal wall motion corresponds to the multiphasic arterial wall excursion in the direction parallel to blood flow during the cardiac cycle. While this motion phenomenon has been well characterized, there is a general lack of awareness regarding its implications for vascular health assessment or even basic vascular physiology. In the last decade, novel estimation strategies and clinical investigations have greatly advanced our understanding of the bi-axial behavior of the carotid artery, necessitating an up-to-date review to summarize and classify the published literature in collaboration with technical and clinical experts in the field. Within this review, the state-of-the-art methodologies for carotid wall motion estimation are described, and the observed relationships between longitudinal motion-derived indices and vascular health are reported. The vast number of studies describing the longitudinal motion pattern in plaque-free arteries, with its putative application to cardiovascular disease prediction, point to the need for characterizing the added value and applicability of longitudinal motion beyond established biomarkers. To this aim, the main purpose of this review was to provide a strong base of theoretical knowledge, together with a curated set of practical guidelines and recommendations for longitudinal motion estimation in patients, to foster future discoveries in the field, toward the integration of longitudinal motion in basic science as well as clinical practice.

Measuring the effect of aging on vibrations of the carotid artery wall using empirical mode decomposition method.

Quantification of arterial elasticity and its dependency to age is considered in this paper. We use radiofrequency (RF) signals from carotid artery ultasonography to evaluate this dependency. Blood pressure, blood flow, and tethering to surrounding tissue are the main causes of the motion of the carotid wall. Tracking carotid artery wall motion from a series of ultrasound B-mode images is challenging due to the presence of noise and variable contrast. Moreover, the process of converting RF signals into the B-mode images causes some information to be lost. Hence, our goal is to extract the carotid wall motions and vibrations from RF signals. After extraction and removing the wall motion by using the phased tracking method combined with continuous wavelet transform, the vibrations of carotid inner wall in different subjects in different ages are compared with each other. Empirical mode decomposition method is used for extracting the first intrinsic mode function for different subjects' vibration and then their zero-crossing rates are compared. The results show the vibrations of the carotid inner wall are clearly decreased by age.