Background and aims: Currently, the severity of the symptomatic carotid stenosis determines the treatment approach. However, it explains only the regional hypoperfusion as the mechanism of cerebral ischemia. Artery-to-artery embolisation remains an important pathogenic mechanism in patients with high-risk carotid plaques. Recently, inflammation has been proposed as the initiating event for plaque rupture and cerebral embolism. Using 18F-fluorodeoxyglucose positron-emission tomography (FDG-PET)/computed tomography (CT) and high resolution magnetic resonance imaging (HR-MRI), we investigated the role of plaque imaging and stroke recurrence in our cohort of patients with recently symptomatic carotid stenosis.
Methods: This ongoing prospective study included consecutive patients within 30-days of recent stroke and ipsilateral carotid stenosis (≥50%). FDG uptake was quantified as mean standardized uptake values (SUV, g/ml). The ratio of T1 hyperintensity of carotid plaque to the ipsilateral sternocleidomastoid muscle (SCM) was recorded on T1-weighted fat suppressed HR-MRI. Patients were followed prospectively for stroke recurrence within 90-days.
Results: Of the 70 patients included in the study, 11 (16%) suffered from recurrent cerebral ischemic event in the same vascular territory within 90-days. Compared to patients without subsequent cerebral ischemic events, patients with recurrent cerebral ischemia showed higher mean T1 carotid-SCM ratio (2.24 versus 1.46; p<0.0001) and higher mean SUV value in the carotid plaque (3.26g/ml versus 1.28g/ml; p<0.0001). Higher T1 carotid-SCM ratio on HR-MRI (OR 3.374, 95%CI 1.561-6.253; p<0.0001), higher mean SUV on FDG-PET (OR 3.646, 95%CI 3.172-11.524; p=0.005) were independent predictors of recurrent cerebral ischemia.
Conclusions: FDG-PET/CT and HR-MRI of carotid stenosis helps in identification of patients at higher risk of subsequent cerebral ischemic events and may aid in better therapeutic decision-making.