ESTIMATING THE PERIODIC COMPRESSION OF THE CAROTID INTIMA-MEDIA USING ULTRASONOGRAPHY: A PROOF OF CONCEPT

International audienceCardiovascular diseases are the leading cause of mortality in the world [1]. The carotid-artery intima-media thickness (IMT) is strongly correlated with cardiovascular diseases [2], but tends to overestimate the risk. Recently a promising predictor has been discovered: the IMT temporal variation during the cardiac cycle, which reflects the arterial stiffness and may be more sensitive than classical risk markers [3]. Few teams have worked on its estimation [3,4,5,6]; existing methods separately delineate the arterial wall in a series of B-Mode images to deduce a single IMT value at each time point. Their evaluation against contours manually traced in B-mode images is tedious and does not exploit the temporal consistency. In this paper, we investigate a less time-consuming process devised to create a temporally consistent manual reference.1. World Health Organization (WHO). Fact Sheet No. 317 at : http://www.who.int/mediacentre/factsheets/fs317/en/2. Bots, ML. et al. Circulation 96(5):1432-1437, 1997.3. Zahnd G. et al. Int J CARS, 9:645-658, 2014.4. Ilea DE et al. IEEE UFFC, 60(1):158-177, 2013.5. Cinthio M. et al. Proc IEEE US Symp 389-391, 2005.6. Zahnd G. et al. Ultrasound Med Biol, 43:1,239-257, 2017

EXTRACTION OF CHARACTERISTIC PATTERNS FROM CAROTID LONGITUDINAL KINETICS

International audienceCardiovascular diseases were in 2016 the leading cause of mortality in the world [1]. Most of them are due to arteriosclerosis, a pathological stiffening of arteries. Screening is traditionally done using risk factors. Carotid longitudinal kinetics (LOKI) has proven to be modified by arteriosclerosis [2, 3]. Although most teams, except [4], use only LOKI amplitude to distinguish atrisk patients from healthy controls, the whole motion may be useful to detect pathological behaviours. In this study typical motion patterns were isolated and their association with cardiovascular risk was investigated.1. World Health Organization (WHO). Fact Sheet No. 317 at: http://www.who.int/mediacentre/factsheets/fs317/en/2. Zahnd G. et al. Med Image Anal, 17 :573–585, 20133. Cinthio M. et al. Am J Physiol Heart Circ Physiol, 291:H394–H402, 20064. Soleimani E. et al. Med Biol Eng Comput 54:12051215, 201

Kalman-Based Carotid-Artery Longitudinal-Kinetics Estimation and Pattern Recognition

International audienceObjectives. The context of the study is the early detection of atherosclerosis. The specific aim of the article is to estimate the longitudinal displacements of the carotid artery wall and assess the discriminative power of the estimated motion patterns to distinguish at-risk individuals from healthy subjects.Methods. Motion estimation builds on block matching with a Kalman filter updating the reference-block gray levels, and incorporates a Kalman filter controlling the trajectory via a model using cosine decomposition. The estimated motion patterns were normalized and provided as input features to a machine-learning-based classifier that automatically assigned healthy or at-risk labels.Results. Evaluated on 113 subjects, the method successfully estimated all but one trajectory, and classification achieved 70% sensitivity and 72% specificity.Conclusions. The proposed method is well suited to estimate 2D (longitudinal and radial) quasi-periodic displacements of the arterial wall in ultrasound image sequences. The estimated motion patterns can contribute to discriminate at-risk from healthy subjects