aneurysmal disease is associated with an inflammatory cell infiltrate and enzymatic degradation of the vessel wall.to detect increased metabolic activity in abdominal aortic aneurysms (AAA) by means of positron emission tomography (PET-imaging).twenty-six patients with AAA underwent PET-imaging.in ten patients, PET-imaging revealed increased fluoro-deoxy-glucose (18-FDG) uptake at the level of the aneurysm. Patients with positive PET-imaging had one or more of the following elements in their clinical history: history of recent non-aortic surgery (n = 4), a painful inflammatory aortic aneurysm (n = 2), moderate low back pain (n = 2), rapid (> 2;5 mm in 6 months) expansion (n = 4), discovery by PET-scan of a previously undiagnosed lung cancer (n = 3) or parotid tumour (n = 1). Five patients with a positive PET scan required urgent surgery within two to 30 days. Among the 16 patients with negative PET-imaging of their aneurysm, only one had recent non-aortic surgery, none of them required urgent surgery, only two had a rapidly expanding AAA, and in only one patient, PET-imaging revealed an unknown lung cancer.these data suggest a possible association between increased 18-FDG uptake and AAA expansion and rupture.