Tests
1st tests to order
abdominal ultrasound
Test
Definitive test (sensitivity and specificity of 92% to 99% and nearly 100%, respectively).[1][2][77]
The ultrasound is performed perpendicular to the aortic axis as oblique views may overestimate the true aortic diameter.[2][5][79]
Unfortunately, ultrasound offers little utility in imaging aneurysms close to the origins of, or proximal to, the renal arteries.[80][81]
Result
abdominal aortic dilation of >1.5 times the expected anterior-posterior diameter of that segment, given the patient's sex and body size; the most commonly adopted threshold is a diameter of ≥3 cm
Tests to consider
computed tomography angiography (CTA)/CT
Test
In selected patients, CT scan is recommended as a first-line investigation to evaluate patients thought to have AAA presenting with recent-onset abdominal or back pain, particularly in the presence of a pulsatile epigastric mass or significant risk factors for AAA.[76] May demonstrate retroperitoneal hematoma, discontinuity of the aortic wall, or extravasation of contrast into the peritoneal cavity, which are all signs of rupture.[13][85]
Also useful in diagnosing aortic aneurysms close to the origins of, or proximal to, the renal arteries.[5][81][85]
The first choice for pre- and intraoperative planning; 0.5 mm slices are desirable and 3D reconstruction is essential for accurate planning.[79][86]
Result
abdominal aortic dilation of >1.5 times the expected anterior-posterior diameter of that segment, given the patient's sex and body size; the most commonly adopted threshold is a diameter of ≥3 cm
positron emission tomography-computed tomography (PET-CT)
erythrocyte sedimentation rate (ESR)/C-reactive protein (CRP)
Test
Supports a diagnosis of possible inflammatory AAA.[5]
Result
elevated
CBC
Test
Leukocytosis and a relative anemia on CBC with positive blood cultures are indicative of infectious AAA.
Result
leukocytosis, anemia
blood cultures
Test
Leukocytosis and a relative anemia on CBC with positive blood cultures are indicative of infectious AAA.
Result
positive
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