What is the external landmark for the aortic EDE?
xiphoid process
What is the internal landmark for the aortic EDE?
spine and acoustic shadow
What is the area of interest for the aortic EDE?
outer wall of aorta
What are three distinguishing features between the IVC and the aorta?
- Aortic wall is thicker (more echogenic) than the IVC.
- Aorta is non-compressible.
- IVC collapses slightly with inspiration (respiratory variability)
What is a positive AAA EDE scan?
aortic wall diameter > 3 cm (measured outer wall to outer wall), assessed in true transverse
Describe three strategies to troubleshoot for bowel gas interfering with visualization.
- Push probe deeper into abdomen and wait 20-30 seconds for gas to dissipate.
- Slide probe off centre and heal probe medially, ensuring spine remains centred and image acquisition in true transverse.
- Flex patients knees to aid in relaxing abdominal wall musculature.
- Ask the patient to take a deep breath in and hold it.
What are two major pitfalls to identifying the aorta versus IVC?
- Pulsatility (both structures can be pulsatile).
- Sidedness (aorta is usually on the patients left, but not always).
Describe a strategy to improve visualization of the aorta in a patient with large amounts of adipose tissue.
lower probe frequency (increases beam penetration)
Describe a strategy to improve visualization of the aorta in a patient with large amounts of adipose tissue.
lower probe frequency (increases beam penetration)
What is a negative scan for AAA?
Visualization of the ENTIRE abdominal aorta from the xiphoid process (i.e. crux of diaphragm) to the iliac bifurcation in transverse. The aortic walls must be clearly seen and there must be no evidence of dilation of the aorta.
