Abstract 19820: 18F-FDG Uptake is Increased in Abdominal Aortic Aneurysms: Localization of Metabolic Activity within Aneurysmal Transition Zones.
Introduction: Inflammation plays an important role in the pathobiology of abdominal aortic aneurysms (AAA). Here we compared vascular inflammation in the aortic wall between patients with AAA and age and gender-matched subjects without AAA, using 18-fluorodeoxyglucose-positron emission tomography (FDG-PET).
Methods and Materials: Thirty-three patients (Median [IQR] 71 years, 82% male), 11 with AAA and 22 age/gender-matched controls without AAA, underwent PET and CT imaging. FDG uptake within the aortic wall was assessed in axial images, from the celiac artery to the iliac bifurcation. Mean target-to-Background ratio (TBR) was determined by dividing aortic wall activity by vena caval blood activity. Additionally, within AAA, TBR was measured in transitional zones of the AAA (the shoulders of the aneurysm) as well as in the opposite wall (figure 1).
Results: Vessel wall inflammation (TBR) was higher in AAA vs. controls (2.82 [1.81] vs. 1.84 [0.59], P<0.001), a difference which remained significant after adjusting for presence of atherosclerosis and atherosclerotic risk factors (p<0.001). Moreover, within AAA, TBR was higher within shoulder regions vs. its opposite wall, (3.47 [2.08] vs. 2.97 [1.85], P<0.0001).
Conclusion: Vascular inflammation is higher in AAA compared to age and gender-matched controls. Furthermore, FDG uptake is highest in the shoulder region of the aneurysm, a region known to contain a high concentration of inflammatory cells. Accordingly, FDG-PET imaging of AAA, with particular attention to the aneurismal transition zones, may provide insights regarding disease mechanisms and opportunities to evaluate therapeutic efficacy.
- © 2010 by American Heart Association, Inc.