Abdominal aortic aneurysm — US / CT

USCTSVS 2018

Measurement and surveillance of an infrarenal abdominal aortic aneurysm.

Applies to

Infrarenal abdominal aortic aneurysm on ultrasound or CT

Does not apply to

Suspected rupture or symptomatic aneurysm (urgent, not surveillance)
Thoracic or thoracoabdominal aneurysms (different thresholds)

What to report

Tap an item to check it off while dictating.

1.Maximum diameter
Outer-to-outer wall, perpendicular to the vessel axis; report the plane used.
Pitfall: An oblique measurement overestimates diameter — always measure perpendicular to the lumen axis.
2.Extent and neck
Longitudinal extent and distance from the renal arteries (proximal neck) for repair planning.
3.Mural thrombus
Presence and thickness of mural thrombus, and true residual lumen.
4.Iliac involvement
Extension into the common iliac arteries and their diameters.
5.Rupture signs
Crescent sign, contour discontinuity, or retroperitoneal hemorrhage — communicate urgently if present.
6.Comparison / growth rate
Compare with priors; growth >0.5 cm/6 months or >1 cm/year warrants referral regardless of absolute size.

Scores & calculators

AAA surveillance interval

SVS 2018

Surveillance interval for an infrarenal abdominal aortic aneurysm by maximum outer-to-outer diameter.

Maximum diameter (outer-to-outer)

Complete the inputs to see the result.

Percentage volume / size change

Percentage change between a prior and current measurement.

Prior value

Current value

Complete the inputs to see the result.

Percentage change = (current − prior) / prior × 100. Use consistent units (diameter or volume).

Sources

SVS practice guidelines on AAA — Chaikof EL et al. J Vasc Surg (2018)

Content review: Content pending clinical review · 2026-07-09

Educational reference for trained clinicians. Verify every result against the cited original guideline before use. Not a substitute for clinical judgment or medical advice.