What is the definitive test used to diagnose an abdominal aortic aneurysm?
A. Abdominal X-ray
B. Arteriogram
C. CT scan
D. Ultrasound
Correct Answer: B. Arteriogram
An arteriogram accurately and directly depicts the vasculature; therefore, it clearly delineates the vessels and any abnormalities.
Option A: An abdominal aneurysm would only be visible on an X-ray if it were calcified. Plain radiography is often performed on patients with abdominal complaints before the diagnosis of AAA has been entertained. Using this method to evaluate patients with AAA is difficult because the only marginally specific finding, aortic wall calcification, is seen less than half of the time. Aortic-wall calcification (see the images below) may appear without aneurysm rim calcification, resulting in a high false-negative rate.
Option C: CT scan doesn’t give a direct view of the vessels. CT permits visualization of the retroperitoneum, is not limited by obesity or bowel gas, detects leakage, and allows concomitant evaluation of the kidneys.
Option D: Ultrasound doesn’t yield as accurate a diagnosis as the arteriogram. Ultrasonography is the standard imaging tool for AAA. When performed by trained personnel, it has a sensitivity of nearly 100% and a specificity approaching 96% for the detection of infrarenal AAA.