Association Between Carotid Atherosclerotic Plaque Calcification and Intraplaque Hemorrhage A Magnetic Resonance Imaging Study

Objective-Carotid intraplaque hemorrhage (IPH) is associated with cardiovascular events. Calcification, which frequently accompanies IPH, may play a role in IPH occurrence. In this study, we aimed to investigate the associations between calcification characteristics and IPH in carotid plaques. Approach and results-One hundred seventeen patients with cerebrovascular symptoms and carotid plaques detected by ultrasound were recruited and underwent multicontrast magnetic resonance imaging. Advanced carotid plaques with composition measured by magnetic resonance imaging were included in the analysis. Carotid calcifications were divided into the following categories: surface, mixed, and deep calcification. They were also classified into single and multiple calcifications according to quantity. Logistic regression models utilizing generalized estimating equations were performed to evaluate the relationship between calcification and IPH. Of 117 subjects, 85 with 142 plaques were included in the final analysis, whereas 32 were excluded because of lack of plaque compositions. Of the 142 plaques, 40 (28.2%) had IPH. Plaques with IPH showed greater prevalence of calcification than those without (87.5% versus 55.9%; P=0.005). After adjusting for age, low-density lipoprotein, maximum wall thickness, and maximum soft plaque thickness, multiple calcifications (odd ratio, 10.1; 95% confidence interval, 3.3-30.4), surface calcification (odd ratio, 29.4; 95% confidence interval, 4.1-210.8), and mixed calcifications (odd ratio, 27.9; 95% confidence interval, 7.3-107.1) were found to be strongly associated with the presence of IPH (all P<0.05). Conclusions-Surface calcification and multiple calcifications in carotid atherosclerotic plaques are independently associated with the presence of IPH, suggesting that both quantity and location of calcification may play important roles in the occurrence of IPH. These findings may provide novel insights for understanding mechanisms of IPH.