Increased Metabolic Activity in Abdominal Aortic Aneurysm Detected by 18F-Fluorodeoxyglucose (18F-FDG) Positron Emission Tomography/Computed Tomography (PET/CT)

ObjectivesAbdominal aortic aneurysms (AAAs) are associated with an inflammatory cell infiltrate and enzymatic degradation of the vessel wall. The aim of this study was to detect increased metabolic activity in the wall of the AAA with 18F-fluorodeoxyglucose (18F-FDG), mediated by glucose transporter protein (GLUTs), using a dedicated hybrid PET/64-detector CT.Design, method and materials14 patients (All male, mean age 73.6 years, range 61–82) with AAA under surveillance underwent PET/CT scanning with 175 MBq of intravenous I8F-FDG. The maximum aneurysm diameter and calcification score were determined on the attenuation correction CT. A volume of interest was placed on the aneurysm sac and the maximum Standardised Uptake Value (SUVmax) measured.ResultsThe mean aneurysm diameter was 5.4 cm (SD ± 0.8). Two aneurysms had the CT characteristics of inflammatory aneurysms. Twelve aneurysms showed increased FDG uptake (SUVmax > 2.5). There was no significant difference in FDG uptake between heavily calcified aneurysms and non-heavily calcified aneurysms (t-test). There was a significant increase in the FDG uptake in the two inflammatory aneurysms compared to the other twelve aneurysms (t-test; P = 0.04).ConclusionThe findings in this study offer in vivo evidence that the AAA wall shows increased glucose metabolism, mediated by the GLUTs: this increased metabolic activity as detected by PET/CT may be present in most AAAs.