Which imaging modality is preferred for screening individuals at risk for abdominal aortic aneurysm?

• A. Ultrasound
• B. CT Scan
• C. MRI
• D. X-ray

Answer: (A)

Ultrasound is the best screening option because it’s safe, inexpensive, widely available, and accurately measures the abdominal aorta to detect aneurysmal dilation. It uses no ionizing radiation and can be performed quickly in primary care or screening settings, making it ideal for routine screening of at-risk individuals. An abdominal aorta diameter of 3 cm or greater defines an aneurysm, and ultrasound reliably identifies this threshold and can be used for ongoing surveillance of growth.

Other imaging modalities have drawbacks for screening. CT provides excellent detail but involves radiation and higher cost, plus contrast risks. MRI avoids radiation but is more expensive and less accessible for routine screening. X-ray offers poor sensitivity for detecting abdominal aortic aneurysms and cannot reliably measure aortic diameter.