Evaluation of a Kalman-based block matching method to assess the bi-dimensional motion of the carotid artery wall in B-mode ultrasound sequences

• Published in: Medical image analysis Vol. 17; no. 5; pp. 573 - 585
• Main Authors: Zahnd, Guillaume, Orkisz, Maciej, Sérusclat, André, Moulin, Philippe, Vray, Didier
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2013; Elsevier
• Subjects: Acoustics; Algorithms; Atherosclerosis; Block matching; Carotid Arteries - diagnostic imaging; Carotid Arteries - physiology; Carotid artery; Carotid Artery Diseases - diagnostic imaging; Carotid Artery Diseases - physiopathology; Data Interpretation, Statistical; Echocardiography - methods; Elastic Modulus; Elasticity Imaging Techniques - methods; Engineering Sciences; Humans; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Kalman filter; Motion; Movement; Pattern Recognition, Automated - methods; Reproducibility of Results; Sensitivity and Specificity; Speckle tracking; Carotid artery; Speckle tracking; Kalman filter; Atherosclerosis; Block matching
• ISSN: 1361-8415; 1361-8423; 1361-8423
• DOI: 10.1016/j.media.2013.03.006

[Display omitted] •We investigate arterial diseases by quantifying the wall stiffness in US imaging.•We focus on the intima-media tissues longitudinal motion, i.e. along the blood flow.•We introduce a novel block matching method based on a specific Kalman filter.•Results on 82 in vivo sequences show good accuracy compared to experts’ tracings.•The longitudinal motion is significantly reduced in at cardiovascular risk patients. We aim at investigating arterial diseases at early stage, by assessing the longitudinal (i.e. in the same direction as the blood flow) motion of the intima-media complex. This recently evidenced phenomenon has been shown to provide relevant and complementary information about vascular health. Our method assesses the longitudinal and radial motion from clinical in vivo B-mode ultrasound sequences. To estimate the trajectory of a selected point during the cardiac cycle, we introduce a block matching method that involves a temporal update of the reference block using a pixel-wise Kalman filter. The filter uses the initial gray-level of the pixel as control signal to avoid divergence due to cumulating errors. The block and search-window sizes are adapted to the tissue of interest. The method was evaluated on image sequences of the common carotid artery, acquired in 57 healthy volunteers and in 25 patients at high cardiovascular risk. Reference trajectories were generated for each sequence by averaging the tracings performed by three observers. Six different computerized techniques were also compared to our method. With a pixel size of 30μm, the average absolute motion estimation errors were 84±107μm and 20±19μm for the longitudinal and radial directions, respectively. This accuracy was of the same order of magnitude as the inter- and intra-observers variability, and smaller than for the other methods. The estimated longitudinal motion amplitude was significantly reduced in at-risk patients compared with healthy volunteers (408±281μm vs. 643±274μm, p<0.0001). Our method can constitute a reliable and time-saving technique to investigate the arterial stiffness in clinical studies, in the objective to detect early-stage atherosclerosis.