Fig. 1

Regions of interest within the abdominal aorta. The abdominal aorta was split into three anatomical regions for analysis demonstrated on the panel on the left. Suprarenal—starting from the level of the origin of the coeliac artery till the upper-most renal artery. Neck—starting from the lower-most renal artery until where the aorta becomes aneurysmal. Aneurysm—starting just after the neck region ends until the aortic bifurcation. The second panel from the left shows a graphic representation of sequential 3 mm polygons taken from the three different aortic regions (suprarenal—blue, neck—green, aneurysm—red). The third panel from the left shows a sagittal view of the abdominal aorta. The right panel shows the volumes of interest drawn on the image analysis programme. CT [HU], computed tomography grey scale bar in Hounsfield units; SUV, positron emission tomography colour scale bar in standard uptake values