Associations between intraplaque hemorrhage and other high-risk plaque features in atherosclerotic plaques

<b>Background:</b> Little is known about the association between intraplaque hemorrhage (IPH) and other features of high-risk carotid atherosclerotic plaques, such as the presence of plaque ulceration, plaque enhancement, and lipid-rich necrotic core (LRNC). This study set out to assess the relationship between IPH and other vulnerable plaque features. <b>Materials and Methods:</b> A retrospective review was done of 102 patients with IPH in one or both of the internal carotid arteries (ICA) on neck MRA between 1/1/2016 and 3/31/2021. IPH was defined as a ≥200% signal intensity of the adjacent sternocleidomastoid muscle on MPRAGE images. All ICA plaques were assessed for the presence or absence of IPH, plaque ulceration, plaque enhancement, and LRNC, as well as IPH volume. IPH volume was measured manually by outlining the region of interest. <b>Results:</b> A total of 102 patients were included, with 88 (86.3%) being male. The average age was 73.5 years (SD = 9.0). Both IPH and LRNC were more commonly seen in the left carotid artery (<i>p</i> = .018 and <i>p</i> = .047, respectively). For right-sided ICAs, there was a significant association between IPH and LRNC (<i>p</i> < .0001). Lesions without IPH were more likely to have plaque enhancement than lesions with IPH (<i>p</i> = .04). For left-sided ICAs, there was also a significant association between the presence of IPH and LRNC (<i>p</i> < .0001). <b>Conclusions:</b> There is a significant association between the presence of IPH and LRNC. An inverse relationship was found between the presence of IPH and plaque enhancement for right-sided plaques. No associations were found between IPH and plaque ulceration.