Objective: The aim of this study was to determine the ideal circulation time of fluorine-18 fluorodeoxyglucose (18F-FDG) in order to detect and quantify atherosclerotic plaque inflammation with PET computed tomography (CT) imaging.
Methods: Fifteen patients underwent multiple time-point imaging at ∼60, 120, and 180 min after 18F-FDG administration. For each time point, global assessment of aortic and carotid 18F-FDG uptake was determined qualitatively by visual assessment and semiquantitatively by calculation of the mean and maximum standardized uptake values (SUV) and the corresponding target-to-background ratio (TBR).
Results: Delayed imaging achieved significant improvement in visualization of atherosclerotic plaque inflammation [Friedman’s χ2 statistic (d.f.=2, n=15)=24.13, P<0.001, Kendall’s W=0.80]. This observation was confirmed by semiquantitative image analysis. At 1 h, the aortic and carotid SUVmean-calculated TBR was 1.05 [95% confidence interval (CI)=0.98, 1.11] and 0.88 (95% CI=0.81, 0.96), respectively. At 3 h, the TBR significantly increased to 1.57 (95% CI=1.28, 1.86; P=0.001) for the aorta and to 1.61 (95% CI=1.36, 1.87; P<0.001) for the carotid arteries. SUVmax-calculated TBRs showed a similar increase over time.
Conclusion: One- and 2-h 18F-FDG PET CT imaging is suboptimal for global assessment of atherosclerotic plaque inflammation compared with imaging at 3 h. Our data support the utilization of 3-h delayed imaging to obtain optimal data for the detection and quantification of atherosclerotic plaque inflammation in human arteries.
aPerelman School of Medicine at the University of Pennsylvania
bDepartment of Radiology, Hospital of the University of Pennsylvania
cDepartment of Radiology, Philadelphia VA Medical Center, Philadelphia, Pennsylvania
dNational Heart Lung and Blood Institute, Bethesda, Maryland, USA
eUniversity Medical Center Utrecht, Utrecht University School of Medicine, Utrecht, The Netherlands
Correspondence to Abass Alavi, MD, MD(Hon), PhD(Hon), DSc, 3400 Spruce Street, Philadelphia, PA 19104, USA Tel: +1 215 662 3069; fax: +1 215 746 0753; e-mail: firstname.lastname@example.org
Received February 15, 2013
Accepted May 21, 2013