Category: Incidental Findings – Vascular (Abdomen)

Abdominal Aortic Aneurysm – ACR 2013

Recommended intervals for initial follow-up imaging of ectactic aortas and abdominal aortic aneurysms

Aortic Diameter Imaging Interval
2.5 - 2.9 cm5 years (defined as ectactic)
3.0 - 3.4 cm3 years
3.5 - 3.9 cm2 years
4.0- 4.4 cm1 year
4.5 - 4.9 cm6 months, also consider surgical or endovascular referral
5.0 - 5.5 cm3-6 months, also consider surgical or endovascular referral
  • “The normal diameter of the suprarenal abdominal aorta is up to 3.0 cm, and that of the infrarenal abdominal aorta is 2.0 cm.”
  • “Aneurysmal dilation of the infrarenal aorta is defined as a diameter ≥3.0 cm or dilation of the aorta ≥1.5 times the normal diameter.”
  • “For abdominal aortic diameters <2.5 cm, follow-up is generally thought to be unnecessary. Because the rupture of smaller abdominal aortic aneurysms is less likely, we recommend longer intervals between follow-up examinations. Follow-up intervals may vary depending on comorbidities and the growth rate of the aneurysm.”

Reference: Khosa F, Krinsky G, Macari M, Yucel EK, Berland LL. 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 2013;10:789-794.

Penetrating Aortic Ulcer – ACR 2013

Annual follow-up is recommended when asymptomatic and more frequent follow-up if symptoms arise, with consideration of surgical or endovascular intervention.

  • “Penetrating aortic ulcers (PAUs) represent disruption of atherosclerotic plaque with penetration of luminal blood for variable distances into or through the aortic wall.”
  • “They may present with acute symptoms and findings, but they may also be recognized as chronic, asymptomatic, incidental findings.”
  • “Studies have shown that the natural history of PAU is variable, unpredictable, and may be one of progressive enlargement resulting in rupture.”

Reference: Khosa F, Krinsky G, Macari M, Yucel EK, Berland LL. 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 2013;10:789-794.

Iliac Artery Aneurysm – ACR 2013

Aneurysm DiameterImaging Interval
<3.0 cmNo explicit recommendation is made
3.0-3.5 cm6 month follow-up initially with cross-sectional imaging; if stable, repeat scanning annually
>3.5 cmClose follow-up or expeditious treatment
  • “Aneurysms that are <3.0 cm in diameter tend to be asymptomatic, rarely rupture, and expand slowly.”
  • “Iliac artery aneurysms >3.5 cm have a greater tendency to rupture.”

Reference: Khosa F, Krinsky G, Macari M, Yucel EK, Berland LL. 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 2013;10:789-794.

Splenic Artery Aneurysm – ACR 2013

Aneurysm DiameterImaging Interval
<2.0 cmYearly follow-up is recommended; follow-up interval may be extended depending on comorbidities and life expectancy
≥2.0 cmEndovascular therapy should be considered
  • “Splenic artery aneurysms occur more frequently in women.”
  • “Risk factors associated with rupture include rapidly increasing size, occurrence in women of childbearing years, cirrhosis (especially associated with α1 antitrypsin deficiency), and symptoms that can be attributable to the aneurysm.”
  • “Smaller aneurysms probably can be safely followed, although the clinical risk factors for rupture should be carefully assessed.”

Reference: Khosa F, Krinsky G, Macari M, Yucel EK, Berland LL. 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 2013;10:789-794.

Renal Artery Aneurysm – ACR 2013

Aneurysm DiameterImaging Interval
1.0 - 1.5 cm1-2 year follow-up imaging
>1.5 - 2.0 cmConsider surgical or endovascular repair
  • “Etiologies include fibromuscular dysplasia (FMD), atherosclerosis, and pseudoaneurysms that may occur after trauma.”
  • “RAAs related to FMD should be considered when there is a classic ‘string of beads’ appearance to the renal artery or when aneurysms occur in younger women, especially when associated with hypertension.”
  • “Pseudoaneurysms typically occur after trauma and are usually located within the parenchyma of the kidney.”
  • “Other aneurysms, not related to FMD or trauma, typically occur at branch points in the renal artery.”
  • Decision to repair a renal artery aneurysm depends on patient age, gender, aneurysm size, and presence of uncontrolled hypertension.

Reference: Khosa F, Krinsky G, Macari M, Yucel EK, Berland LL. 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 2013;10:789-794.