Can software be developed to automatically aid in the measurement of abdominal aortic aneurysms, and is there a way to predict future rupture or growth of abdominal aortic aneurysms.

Hypothesis: ECG-gated multidetector CT and ECG-gated Dual Source CT can be used to create multiple volumetric datasets of the abdominal aorta over the time period of the cardiac cycle, allowing for direct and regional calculations of abdominal aortic distensibility over the entire volume of the abdominal aorta, providing insight into risk of abdominal aortic aneurysm rupture and early large vessel stiffness.

Inclusion Criteria:

• AAA must be at least 3 cm to a maximum 4.9cm cross-sectional diameter.
• BMI 31 or less.
• Creatinine results <2.0 and within six months prior to scan.
• US patients must have only normal creatinine (0.9 to 1.4) for one year before study visit.
• Patients who are originally scheduled for US, who are then subsequently rolled in this study, will have only a ultrasound scan as followup after the initial CTA.

Exclusion Criteria:

• Creatinine > 2.0.
• Creatinine <0.9 or >1.4 for those who are scheduled for US.
• Atrial fibrillation or other arrythmia.
• Known AAA greater than 5 cm in size.
• Allergy to contrast dye.

Patients undergoing imaging of their abdominal aortic aneurysm