A fast 2D tissue motion estimator based on the phase of the intensity enables visualization of the propagation of the longitudinal movement in the carotid artery wall

A fast 2D motion estimator has been developed and evaluated. The method does not utilize block-matching or iterative solutions and is thus more computationally efficient and suitable for real-time motion estimation over the entire image. The method has been evaluated on 1) phantom measurements and 2) in vivo on the carotid artery wall of 17 subjects, where measurements of the longitudinal displacement of the intima-media complex were compared to our previously validated method. The mean error of the phantom measurements was 2.0±3.3% (velocities between 2-15 mm/s; approx. 60 million estimations). In the in vivo measurements the mean difference (validated-proposed) was 18±44μm. Further the method has enabled visualization of the propagation of the longitudinal movement in the carotid artery wall. Several different phases of the longitudinal propagation, which seem to be connected to the multi-phasic pattern of the longitudinal movement, can be seen. All phases of the longitudinal propagation seem to originate from the direction of the heart.