ARFI beam sequence performance as evaluated by trained readers: Plaque detection

ARFI and SWEI have been demonstrated to be capable of detecting atherosclerotic plaques both ex vivo and in vivo. In order to ensure the best possible plaque detection capability, the most appropriate beam sequences must be used. A method for determining the performance of beam sequences is presented in the form of a reader evaluation study using trained readers to evaluate parametric image sets. Nine ARFI/SWEI beam sequences were applied in arterial mimicking phantoms with soft and hard inclusions, and 7 sequences were applied in 22 arterial segments from 6 pigs. The sequences consisted of 3 types of excitations: a single F/1.5 pulse, a single F/3 pulse, and two F/1.5 pulses, spaced 0.8 ms apart. These 3 excitation methods were combined with 3 types of tracking to generate the 9 total sequences: 1:1 Single A-line receive, 4:1 parallel receive and 4:1 parallel receive tracking lateral to the region of excitation (SWEI). Beam sequences that tracked in the region of excitation performed best in both phantoms and ex vivo arteries. The ranking of beam sequence performance was generally consistent in both phantom and ex vivo arteries.