Objectives: Inflammation is important in both the pathogenesis and outcome of atherosclerosis. Current imaging techniques provide anatomic data but no indication of plaque inflammation. We tested the hypothesis that plaque inflammation could be assessed in vivo by (18)FDG-PET and that plaque inflammation could increase the risk of recurrent vascular events and poor response to treatment in a pilot study.
Patients and methods: Thirteen patients (median age 66.1 years [55-82 years]) with recent carotid territory TIA or ischemic stroke and internal carotid artery (ICA) stenosis > or =50% were studied. Angiography and (18)F-fluorodeoxyglucose-positron emission tomography ((18)FDG-PET) imaging were carried out in all patients. Treatment for carotid stenosis in each patient was selected by the attending physician and consisted in medical treatment, endarterectomy or stent placement. During 6 months of follow-up, the specific end points assessed were the occurrence of any stroke, death, or re-stenosis.
Results: Patients with symptomatic carotid atherosclerosis were imaged using (18)FDG-PET. Strong (18)FDG uptake (SUV> or =2.7) was seen in 11 of 13 (85%) carotid lesions. Among these patients two died during follow-up, 3 had recurrent non-fatal ipsilateral ischemic stroke and 1 patient who had undergone stenting had non-symptomatic re-stenosis in control studies. There was a significant correlation between the (18)FDG uptake and degree of ICA stenosis detected by angiography.
Conclusion: Carotid atherosclerotic plaques contain a variable degree of inflammation which can be assessed in vivo by means of FDG and PET. The prognostic value of this marker is, however, still unclear and needs further study.