A new ultrasound imaging indicator for vulnerability evaluatation of carotid atherosclerotic plaques

Rupture of atherosclerotic plaques is the key factor leading to ischemic stroke. In conventional ultrasound, B-mode imaging and/or color flow/pulsed wave Doppler can be used to evaluate the stenosis of blood vessels but not the vulnerability of plaques. In this paper, we propose an ultrasound strain rate imaging based indicator called mean maximum strain rate (MMSR) to evaluate the vulnerability of carotid atherosclerotic plaques validated using multi-sequence magnetic resonance (MR) imaging characterization. This indicator was tested on 47 plaques from 34 human subjects. Statistical significance was found (p=0.01) between stable plaques and vulnerable plaques. The sensitivity and specificity at the cost effective point of receiver operating characteristic (ROC) curve is 76% and 81%, respectively. This indicator is shown to be effective in evaluating the vulnerability of carotid atherosclerotic plaques.