Abdominal aorta U/S

The abdominal aorta is considered aneurysmal if the diameter is more than or equal to 3 cm. The common iliac arteries have a diameter of 1.5 cm or less. Use a curvilinear or cardiac probe. Make sure to adjust depth during the scan.
STEPS
1.  Pan-scan the abdominal aorta in transverse

- Hold the probe in transverse orientation, anterior-posterior to body, depth at 16-21cm (adjust according to patient size).
- Rapidly scan down the abdominal aorta from proximal to bifurcation.
- Note that the aorta is deeper as it enters the diaphragm, and shallower as it runs down the body.
- Visually inspect for any widening of the aorta.

2. Pan-scan the abdominal aorta in sagittal
- Repeat using the longitudinal / sagittal orientation.
- Now scan from bifurcation to proximal aorta.

3. Detailed scan of the abdominal aorta in transverse
- Use appropriate depth setting, 16-21cm at the proximal aorta, reducing depth as the probe moves downwards towards bifurcation, keeping the aorta in the centre of the screen.
- Stop and measure the proximal (above the celiac trunk), mid, and distal (before bifurcation) aorta
- Measure both AP and transverse diameter
- Repeat using the longitudinal / sagittal orientation.

4. Scan the iliac arteries
- Follow the common right and left iliac arteries until they divide into the internal and external iliac arteries
- The iliac veins run next to the arteries so don't be surprise if multiple vessels are apparent.

abdominal aorta scan technique



Transverse scan of AAA



Longitudinal scan of AAA





Watch a comprehensive video tutorial on performing the ultrasound of the abdominal aorta





References
1. Bentz S, Jones J. Accuracy of emergency department ultrasound scanning in detecting abdominal aortic aneurysm. BMJ 2006;23(10):803.

2. Barkin AZ, Rosen CL. Ultrasound detection of abdominal aortic aneurysm. Emerg Med Clin North Am 2004, Aug;22(3):675-82.

3. Knaut AL, Kendall JL, Patten R, Ray C. Ultrasonographic measurement of aortic diameter by emergency physicians approximates results obtained by computed tomography. J Emerg Med 2005, Feb;28(2):119-26.

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