Comparison of symptomatic and asymptomatic atherosclerotic carotid plaque features with in vivo MR imaging

Purpose: To retrospectively determine if in vivo magnetic resonance (MR) imaging can simultaneously depict differences between symptomatic and asymptomatic carotid atherosclerotic plaque. Materials and Methods: Institutional review board approval and informed consent were obtained for this HIPAA-compliant study. Twenty-three patients (21 men, two women; mean age, 66.1 years +/- 11.0 [standard deviation]) with unilateral symptomatic carotid disease underwent 1.5-T time-of-flight MR angiography and 1.5-T T1-, intermediate-, and T2-weighted MR imaging. Both carotid arteries were reviewed. One observer recorded quantitative and morphologic information, which included measurement of the area of the lumen, artery wall, and main plaque components; fibrous cap status (thick, thin, or ruptured); American Heart Association (AHA) lesion type (types I-VIII); and location (juxtaluminal vs intraplaque) and type of hemorrhage. Plaques associated with neurologic symptoms and asymptomatic plaques were compared with Wilcoxon signed rank and McNemar tests. Results: Compared with asymptomatic plaques, symptomatic plaques had a higher incidence of fibrous cap rupture (P=.007), juxtaluminal hemorrhage or thrombus (P=.039), type I hemorrhage (P=.021), and complicated AHA type VI lesions (P=-.004) and a lower incidence of uncomplicated AHA type IV and V lesions (P=.005). Symptomatic plaques also had larger hemorrhage (P=.003) and loose matrix (P=.014) areas and a smaller lumen area (P=.008). No significant differences between symptomatic and asymptomatic plaques were found for quantitative measurements of the lipid-rich necrotic core, calcification, and the vessel wall or for the occurrence of intraplaque hemorrhage or type II hemorrhage. Conclusion: This study revealed significant differences between symptomatic and asymptomatic plaques in the same patient. (c) RSNA, 2006.