P2.08 ESTIMATION OF LONGITUDINAL WALL MOVEMENT IN COMMON CAROTID ARTERY USING ROBUST BLOCK-MATCHING WITH AN EXTRA BLOCK

Abstract

Technological developments made it possible to detect a longitudinal motion of the arterial wall. Our previously presented method can estimate this motion with high accuracy, but the method requires ultrasound images of very high quality. The aim of this study was to evaluate a novel method for estimating the longitudinal movement with respect to both robustness and accuracy. The developed method uses ultrasound B-mode information to give a sub-pixel estimation of the movement of an area chosen in a cineloop. The method was evaluated in vivo on the right common carotid artery of healthy volunteers (2 measurements each on 10 males; age 27–57 years and 10 females; age 25–49 years). Figure 1 shows the longitudinal arterial wall movement of one volunteer. Three phases of longitudinal wall movement can be detected; an antegrade movement (LMov1) in early systole, a following retrograde movement (LMov2), and a subsequent antegrade movement (LMov3). The magnitude of the three phases of movement was mean 312 μm (SD 197), −706 μm (222) and 577 μm (218), respectively. The intra-observer variation for the different phases of movement was 21%, 13%, and 17%, respectively, compared to 14%, 13%, and 16% using our previously presented method. Figure 2 shows a Bland-Altman plot comparing the two methods. While the new method could make estimations in all cineloops, our previously presented method failed in six of them. The study shows that the new method seems to be more robust than our previously presented method with similar tracking accuracy.