Noninvasive Assessment of Abdominal Aortic Aneurysm (AAA) Wall Structural Integrity and Inflammation as Predictors of Expansion and/or Rupture

Eligible subjects in this study will have either a known abdominal aortic aneurysm (AAA) or because they do not have an AAA (control group). The purpose of this research study is to further study, through FEA, changes that occur in the mechanical properties of the aortic wall. The investigator will compare two radiotracers, 18F-FDG and 11C-PBR28 to determine if one provides more useful and reliable information about inflammation. 18F-FDG and 11C-PBR28 are radioactive drugs that will be used for imaging during the PET-CT scan. The investigator will also compare the results describing the mechanical properties of the AAA wall to the degree of inflammation in that wall as determined by PET-CT imaging to define new and better predictors of AAA growth and/or rupture.