Abstract 692: Serial 3 Tesla Magnetic Resonance Imaging Identifies Changes in Carotid Plaque Morphology Following Acute Cerebrovascular Events
Introduction: Rupture of a carotid atherosclerotic plaque is associated with a high risk of early recurrent stroke - approximately 1 in 5 patients will have a further event within 3 months. The ability to identify healing of an acutely ruptured plaque could aid in risk stratification following acute cerebrovascular events.
Hypothesis: Serial magnetic resonance imaging (MRI) of acutely ruptured carotid plaque can identify changes in plaque morphology over time.
Methods: 20 patients presenting with acute minor strokes or transient ischaemic attacks underwent MRI using T1-, T2-, and proton density(PD) -weighted turbo spin echo imaging to 10mm either side of the carotid bifurcation (in-plane resolution 0.47mm x 0.47mm, slice thickness 2mm). Repeat scans were performed at a mean of 9.1 weeks; 5 patients underwent carotid endarterectomy and were excluded. Plaques were graded according to the MRI modified AHA system. Results and
Conclusion: The median time from symptoms to scan was 47.2 hours. 12 patients showed signs of vulnerable plaque at the initial scan (AHA type VI). Of these 12 cases, 2 showed evidence of fibrous cap healing and were re-classified as type IV/V at follow-up (figure A⇓, T1 weighting). However, the ten remaining cases of AHA VI plaque showed either no or only partial signs of healing, either due to ongoing cap rupture (figure B⇓) or to the continued presence of intra-plaque haemorrhage (figure C⇓). In conclusion, this is the first series describing the use of serial MRI to distinguish between healing and non-healing carotid plaques following acute cerebrovascular events. Further work will investigate the relationship between the plaque changes seen and clinical outcomes.