Background and aims: Symptomatic carotid stenosis is associated with an increased risk of early stroke recurrence. Currently, therapeutic decisions are largely based on the luminal narrowing, which mainly explain the cerebral ischemia related to regional hypoperfusion. Plaque inflammation, the initiating event for plaque rupture and thromboembolism (artery-to-artery embolism), is not evaluated routinely in patients with carotid stenosis. Using combined 18F-fluorodeoxyglucose positron-emission tomography (FDG-PET)/computed tomography (CT), we investigated the role of plaque inflammation and stroke recurrence in our cohort of stroke patients with recently symptomatic carotid stenosis.
Methods: This ongoing prospective study aims to include consecutive patients within 30-days of recent stroke and ipsilateral carotid stenosis (≥50%). FDG uptake is quantified as mean standardized uptake values (SUV, g/ml). Patients are followed prospectively for stroke recurrence. Embolic potential of the carotid plaque is estimated by presence of spontaneous microembolic signals (MES) on continuous transcranial Doppler monitoring of the middle cerebral arteries (MCA) for 40 minutes.
Results: Of the 22 patients included in the study, 5 suffered from recurrent cerebral ischemic event in the same vascular territory within 90 days. In patients with recurrent cerebral ischemia, the mean SUV value in the carotid plaque on the side of symptomatic carotid stenosis was higher (3.46g/ml) as compared to the patients without stroke recurrence (1.72g/ml; p=0.03). MES were noted in 3/5 cases with recurrent cerebral ischemia as compared to 2/17 cases (p=0.001)
Conclusions: FDG-PET/CT aids in the imaging of plaque inflammation and identification of patients with higher risk of subsequent cerebral ischemic events. This ongoing study intends to develop a robust prediction model for risk stratification based on luminal stenosis and plaque characteristics for better therapeutic decision-making.