ARFI beam sequence performance as evaluated by trained readers: Plaquedetection

ARFI and SWEI have been demonstrated to be capable of detectingatherosclerotic plaques both ex vivo and in vivo. In order to ensure the bestpossible plaque detection capability, the most appropriate beam sequences mustbe used. A method for determining the performance of beam sequences is presentedin the form of a reader evaluation study using trained readers to evaluateparametric image sets. Nine ARFI/SWEI beam sequences were applied in arterialmimicking phantoms with soft and hard inclusions, and 7 sequences were appliedin 22 arterial segments from 6 pigs. The sequences consisted of 3 types ofexcitations: 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 oftracking to generate the 9 total sequences: 1:1 Single A-line receive, 4:1parallel receive and 4:1 parallel receive tracking lateral to the region ofexcitation (SWEI). Beam sequences that tracked in the region of excitationperformed best in both phantoms and ex vivo arteries. The ranking of beamsequence performance was generally consistent in both phantom and ex vivoarteries.