Increased 18F-FDG uptake is predictive of rupture in a novel rat abdominal aortic aneurysm rupture model.

Abdominal aortic aneurysm (AAA) is a significant medical problem, with a high mortality rate. More than 50% of AAA patients present with rupture, without a previous AAA diagnosis. Currently, increased aortic diameter represents the greatest risk measurement for human AAA rupture; however, small AAAs rupture, whereas large AAAs are incidentally discovered. Clinical practice would benefit from a reliable, noninvasive test of impending aortic rupture. Inflammation, specifically infiltration by activated macrophages, plays a significant role in AAA development and rupture. Glucose is the primary energy source for inflammatory cells, including macrophages. A number of studies have suggested a role for 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) imaging to detect aortic wall inflammation.1 Sakalihasan et al2 correlated increased AAA 18F-FDG uptake with associated symptoms and rapid aortic enlargement. The process of aortic rupture remains poorly understood, with a lack of adequate noninvasive imaging and biological insight. We utilized the lysyl oxidase inhibitor β-aminopropionitrile (BAPN) with the porcine pancreatic elastase (PPE) model to generate a novel, reproducible model of AAA rupture in the rat. We hypothesized that aortic rupture would be associated with an increased inflammatory response in the AAA wall, and this increased inflammation could be identified noninvasively by 18F-FDG micro-PET.