Longitudinal follow-up of ascending versus abdominal aortic aneurysm formation in angiotensin II-infused ApoE−/− mice

Abstract

Purpose: To explore new imaging techniques to elucidate some of the differences between both abdominal and ascending aortic aneurysms in the angiotensin II mouse model. Procedures: Angiotensin II-infusing pumps were implanted in male ApoE−/− mice (n = 10). In vivo micro-CT, ultrasound and Positron emission tomography (PET) were used to follow up on aneurysm formation. Results: We observed that the ascending aortic aneurysm gradually increased in size over the course of 49 days, while the abdominal aneurysm appeared much more suddenly in between scan times, or in some cases was not detectable at all on micro-CT. Diastolic backflow was detected from day 7 on in the ascending aorta, but not in the abdominal aorta of animals developing an aneurysm at the respective location. Finally PET 18F-FDG uptake was increased in both the ascending and the abdominal aneurysmatic aorta at day 14, but not at day 7. Conclusions: Novel imaging techniques should be explored in-depth to come to a better understanding of the difference in morphology and hemodynamics between ascending and abdominal aneurysms in angiotensin II-infused ApoE−/− mice.

Keywords

• Small animal imaging
• In vivo micro-CT
• High-frequency ultrasound
• PET
• Angiotensin II
• Ascending aortic aneurysm