Abstract 733: 18 F-FDG PET Imaging Predicts Progression of Carotid Stenosis: A Prospective 2-Year Follow-up Study
Background: Inflammation plays an important role in the progression of advanced atherosclerotic lesions. FDG-PET imaging has been validated in humans for measurement of plaque inflammation. Accordingly, we tested the hypothesis that carotid FDG PET signal predicts subsequent carotid plaque progression (stenosis) in patients with carotid stenosis.
Methods: We studied 15 patients with carotid stenosis [Age 71±9 yr, 65% males] who underwent carotid PET imaging (3 hr after FDG) prior to carotid endarterectomy (CEA). FDG uptake was examined along the vessel ipsilateral to CEA and activity within the 1.5 cm-long segment with the highest FDG uptake was recorded. Target-to-background ratio (TBR) was calculated by dividing vascular FDG uptake by venous blood activity. Thereafter, progression of carotid artery disease was determined by serial carotid ultrasound (US) examinations. Progression was defined as a change in the grade of stenosis severity (change of 0, 1, or ≥2 US grades of stenosis over 2 years). PET and ultrasound measurements were done independently, in a blinded manner.
Results: TBR was significantly higher in the patients with any progression of stenosis (vs. without), [Median (IQR) 2.64 (0.25) vs. 1.56 (0.43)], (P=0.0071). Further, TBR varied according to the rate of progression [Median (IQR) 1.56 (0.43) vs. 2.41 (0.83) vs. 3.66 (2.03)] for increase of 0, 1 and ≥2 US grades of stenosis, respectively, (P=0.02).
Conclusion: This preliminary observation suggests that FDG uptake may predict progression of carotid stenosis. Additional validation in a larger cohort will be required prior to generalization of these findings.