Atherosclerotic plaque evolution predicts cerebral ischemic events in patients with intracranial atherosclerosis: a multicentre longitudinal study using high-resolution MRI

Background: Intracranial atherosclerosis (ICAS) is the leading cause of ischemic stroke in Asians and the recurrent rate remains high despite the optimal medical treatment. This study aimed to confirm that follow-up high-resolution magnetic resonance imaging (hrMRI) provided essential values in predicting subsequent cerebral ischemic events in patients with ICAS.

Methods: Patients with moderate to severe stenosis in the middle cerebral artery (MCA) defined by magnetic resonance (MRA) or computed tomography angiography (CTA) were recruited from three centers retrospectively. Detailed plaque composition was analyzed on baseline and follow-up hrMRI. Multivariate Cox proportional hazards regression analysis was used to identify the key risk factors for predicting subsequent ischemic events.

Results: Among 152 patients, a total of 86 patients with MCA atherosclerotic stenosis underwent follow-up hrMRI exams and ipsilateral cerebral ischemic events occurred in 12 patients during a 1-year follow-up. Analyses showed the predictors of ischemic events were age (adjusted Hazard ratio (HR) = 0.942; 95% Confidence Interval (CI), [0.903, 0.983]; p = 0.006), progression of plaque burden (HR = 3.818; 95% CI [1.117, 13.051]; p = 0.033), vessel expansion (HR = 5.173; 95% CI [1.077, 24.838]; p = 0.040) and enhancement ratio progression (HR = 6.144; 95% CI [1.480, 25.511]; p = 0.012). The combined model achieved a concordance index of 0.804 (95% CI [0.658, 0.950]).

Conclusion: Longitudinal hrMRI evaluation improved the accuracy in identifying higher-risk patients with intracranial atherosclerosis.

Key points: Question Can longitude high-resolution magnetic resonance imaging (hrMRI) help clinicians observe intracranial plaque evolution? Findings Compared with the baseline exam, intracranial plaque evolution distinguished by follow-up hrMRI exam showed a higher accuracy in predicting subsequent ischemic events. Clinical relevance Longitudinal high-resolution magnetic resonance vessel wall imaging enables dynamic observation and evaluation of the changes in plaque characteristics among intracranial atherosclerosis patients. Atherosclerotic plaque evolution revealed by repeated exams can strengthen the risk stratification of patients with intracranial atherosclerosis.