Magnetic Resonance Imaging
Magnetic Resonance Imaging (MRI) was used to evaluate the time-course evolution of the aneurysm formation in response to Ang II. MRI assessments were repeated every day for five days (0, 24, 48, 72 and 96 hours from the starting of Ang II infusion). The number of averaged experiments (NA) was 2 and the total acquisition time for this experiment was 12 minutes and 17 seconds. In the most caudal position of the image volume a flow saturation slice was used to eliminate the signal of venous flow. Magnetic Resonance Angiography (MRA) data were processed using ImageJ 1.51 (NIH, Bethesda, Maryland, USA). The aorta areas, comprising aortic wall and lumen, and the lumen areas were measured by two independent observers using ParaVision 3.1 software (Bruker, Ettlingen, Germany). Regions of interest were manually drawn and the mean of the two measurements were calculated. The aortic areas were measured on every 1-mm slice from the superior mesenteric artery to 10 mm above it.