Purpose: To utilize 40-slice electrocardiographically (ECG)-gated cine computed tomographic angiography (CTA) to characterize normal aortic motion during the cardiac cycle at relevant anatomical landmarks in preoperative abdominal aortic aneurysm (AAA) patients.
Methods: In 10 consecutive preoperative AAA patients (10 men; mean age 78.8 years, range 69-86), an ECG-gated CTA dataset was acquired on a 40-slice CT scanner using a standard radiation dose. CTA quality was graded and scan time was measured. Pulsatility measurements at multiple relevant anatomical levels were performed in the axial plane. Changes in aortic circumference were determined for both the aortic wall and the luminal diameter.
Results: All 10 CT scans were of good quality. All patients could be scanned in 14 to 33 seconds (mean 21). At each anatomical level measured, there was a 2.2- to 3.4-mm increase in the aortic wall circumference per cardiac cycle. A similar increase was observed in luminal circumference, with a 2.4- to 3.6-mm increase per cycle.
Conclusion: This study introduces the concept of dynamic cine CTA imaging of aortic motion, providing insight into the pathophysiology of abdominal aortic and iliac pulsations. Patients with AAAs selected for EVAR demonstrate changes in aortic circumference with each cardiac cycle that may have consequences for endograft sizing and future design. The potential for graft migration, intermittent type I endoleak, and poor patient outcome following EVAR can be anticipated. Complex aortic dynamics deserve increased scrutiny in an effort to prevent potential complications.