| Abdominal Aortic Aneurysm Diameter | Follow-up Imaging Interval | Notes |
| 2.5 – 2.9 cm | 5 years | |
| 3.0 – 3.4 cm | 3 years | |
| 3.5 – 3.9 cm | 2 years | |
| 4.0 – 4.4 cm | 1 year | |
| 4.5 – 4.9 cm | 6 months | Consider surgical or endovascular referral |
| 5.0 – 5.5 cm | 3-6 months |
| Iliac Artery Aneurysm Diameter | Follow-up Imaging Interval | Notes |
| <3 cm | Asymptomatic, grow slowly, rarely rupture | |
| 3.0 – 3.5 cm | Follow-up in 6 months, then annually if stable | |
| >3.5 cm | “Follow more closely” | Consider surgical or endovascular referral |
| Finding | Follow-up Imaging Interval | Notes |
| Penetrating Atherosclerotic Ulcer | Annual follow-up CT if asymptomatic | Consider surgical or endovascular referral |
| Splenic Artery Aneurysm | Annual | >1 year f/u for smaller aneurysms based on life expectancy, comorbidities |
| Renal Artery Aneurysm
1-1.5 cm |
1-2 years | >1.5 cm, consider surgical or endovascular referral |
| Other Aneurysms | Treatment recommended for aneurysms >2 cm diameter, or any pancreaticoduodenal aneurysms |
References:
Khosa, F., et al. (2013). “Managing Incidental Findings on Abdominal and Pelvic CT and MRI, Part 2: White Paper of the ACR Incidental Findings Committee II on Vascular Findings.” J Am Coll Radiol 10: 789 – 794.