Irregularity of Carotid Plaque Surface Predicts Subsequent Vascular Event: A MRI Study

Abstract

Background: The relationship between plaque compositions and irregular plaque surface and its predictive value for vascular events (VEs) are unknown.

Purpose: To investigate the relationship between irregular carotid plaque surface and plaque compositional features and its predictive values for future VEs utilizing magnetic resonance (MR) vessel wall imaging.

Study type: Prospective study.

Population: In total, 140 patients with cerebrovascular symptoms were recruited.

Field strength/sequence: 3T, black blood T₁ -weighted, black blood T₂ -weighted, 3D time-of-flight, magnetization-prepared rapid acquisition gradient echo (MP-RAGE), and 3D motion sensitized driven equilibrium rapid gradient echo (MERGE).

Assessment: The carotid artery stenosis and maximum wall thickness (Max WT) were measured. The presence/absence of irregular carotid plaque surface, calcification, lipid-rich necrotic core (LRNC), intraplaque hemorrhage (IPH), and fibrous cap rupture was determined. After baseline examination, all patients were followed-up for at least 1 year to record the VEs.

Statistical tests: Independent t-test, Mann-Whitney U-test, Chi-square, logistic regression, and Cox regression were used.

Results: In total, 82 (58.6%) had irregular plaque surfaces. The carotid Max WT, stenosis, and the presence of surface calcification, LRNC and IPH were significantly associated with irregular plaque surface (all P < 0.05). After adjusted for baseline confounding factors, these associations remained statistically significant (all P < 0.05). During the median follow-up time of 12.1 months, 37 (26.4%) patients had VEs. Univariable Cox regression analysis showed that the irregular carotid plaque surface was significantly associated with subsequent VEs (hazard ratio [HR], 11.02; 95% confidence interval [CI], 2.65-45.85; P = 0.001). After adjusted for baseline and follow-up confounding factors, this association remained statistically significant (HR, 13.03; 95% CI, 1.71-99.42, P = 0.013). After further adjusted for intracranial stenosis, this association also remained statistically significant (HR, 12.57; 95% CI, 1.63-96.83, P = 0.015).

Data conclusion: The morphology of carotid atherosclerotic plaque surface determined by MR vessel wall imaging, particularly irregular plaque surface, is an independent predictor for subsequent vascular events.

Level of evidence: 1 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2020;52:185-194.

Keywords: atherosclerosis; carotid artery; irregular plaque surface; vascular events.