AAA: ULTRASOUND GUIDELINES

III. Indications/Contraindications

Indications for ultrasound of the abdominal aorta include but are not limited to:

A. Diagnostic Evaluation for an Abdominal Aortic

Aneurysm 

1. Palpable or pulsatile abdominal mass.

2. Unexplained lower back pain , flank pain, or abdominal pain.

3. Follow-up of a previously demonstrated abdominal aortic aneurysm.

4. Follow-up of patients with an abdominal aortic and/or iliac endoluminal stent graft.

B. Screening Evaluation for an Abdominal Aortic Aneurysm

1. Men 65 years or older.

2. Women 65 years or older with cardiovascular risk  factors.

3. Patients 50 years or older with a family history of aortic and/or peripheral vascular aneurysmal

disease.

4. Patients with a personal history of peripheral vascular aneurysmal disease.

Groups with additional risk include patients with a history of smoking, hypertension, and certain connective tissue diseases (eg, Marfan syndrome).

There are no absolute contraindications to ultrasound of the aorta. If aortic rupture or dissection is clinically suspected, ultrasound is usually not the examination of choice.

IV. Written Request for the Examination

The written or electronic request for an ultrasound examination should provide sufficient information  to allow for the appropriate performance and interpretation of the examination.

The request for the examination must be originated by a physician or other appropriately licensed health care provider or under their direction. The accompanying clinical information should be provided by a physician or other appropriate health care provider familiar with the

patient’s clinical situation and should be consistent with relevant legal and local health care facility requirements.

V. Specifications of the Examination

A. Diagnostic Examination

The examination includes the following, when feasible:

1. Abdominal aorta:

a. Longitudinal images (along the long axis of the vessel):

i. Proximal;

ii. Mid;

iii. Distal.

b. Transverse images (perpendicular to the long axis of the vessel):

i. Proximal (near diaphragm);

ii. Mid;

iii. Distal.

c. Measurements:

i. Measurements of the proximal, mid, and distal aorta should be obtained.

Measurements are taken at the greatest diameter of the aorta from outer edge to outer edge.

ii. If an aneurysm is present, the maximal size and location of the aneurysm should be documented and recorded. The relationship of the dilated segment to the renal arteries and to the aortic bifurcation should be determined if possible.

iii. A measurement of the length of the aneurysm is not necessary.

2. Common iliac arteries:

a. Longitudinal images of the proximal right and left common iliac arteries (along the long axis of the vessel).

b. Transverse images (perpendicular to the long axis of the vessel) of the proximal common iliac arteries just below the bifurcation.

c. Measurement of the widest visualized portion of each common iliac artery from outer edge to outer edge.

Color Doppler and/or spectral Doppler imaging with waveform analysis of the aorta and iliac arteries may provide additional information.

After endoluminal graft placement, color (or power) Doppler imaging and spectral Doppler imaging are required to document the presence or absence of endoleaks.

Interobserver measurements of an aortic aneurysm can vary by as much as 5 mm. This variation makes visual comparison with previous studies particularly important to determine whether a significant change in size has occurred.

B. Screening Examination for an Abdominal Aortic Aneurysm

1. Abdominal aorta:

a. Longitudinal images (along the long axis of the vessel):

i. Proximal;

ii. Mid;

iii. Distal.

b. Transverse images (perpendicular to the long axis of the vessel):

i. Proximal (near diaphragm);

ii. Mid;

iii. Distal.

C. Interpretation of the screening examination should include at least 3 categories:

1. Positive—Infrarenal abdominal aortic aneurysm greater than or equal to 3 cm in diameter or greater than or equal to 1.5 times the diameter of

the more proximal aorta.

The latter definition is particularly important in women.

2. Negative—No infrarenal abdominal aortic aneurysm.

3. Indeterminate—Aneurysmal status not defined because of nonvisualization or only partial visualization of the infrarenal abdominal aorta.

The report should also state whether the suprarenal aorta was seen and, if seen, should reflect whether it is normal.