High intensity signal on MIP images from routine TOF-MRA of carotid atherosclerotic plaque indicates higher volume of intraplaque hemorrhage and lipid rich necrotic core

Background Carotid intraplaque haemorrhage (IPH) and lipid rich necrotic core (LRNC) have been associated with accelerated plaque growth, luminal narrowing, future surface disruption and development of symptomatic events. It has also been reported that unstable plaque which contains LRNC or IPH is associated with an increased number of emboli after carotid artery stenting. Therefore, a simple screening method to detect these components in the plaque is needed. Maximum intensity projection (MIP) images from time-of-flight MR angiography (TOF-MRA) are widely and routinely used for screening carotid artery stenosis. This study examined whether high-intensity signal (HIS) in the plaque on MIP images from routine TOF-MRA could quantify IPH.