11C-PBR28 autoradiography. Representative autoradiography (A, B, E, F), block face photographs (C, G), and fusion images (D, H) of a representative IPPE control (A-D) and an APPE AAA (E-H). Note that the AAA (in E-H) is collapsed causing folds in the aortic wall. 11C-PBR28 uptake is increased in the APPE AAA (AMRARG 28.6 ± 8.0) wall compared to the control aortic wall (AMRARG 4.7 ± 0.2). The aortic wall (red arrows), blood pool (yellow arrows), psoas musculature (black arrows), suture material (green arrow), and gut activity (blue arrow) are marked.