How is an abdominal aortic aneurysm (AAA) typically diagnosed?

An abdominal aortic aneurysm (AAA) is typically diagnosed using imaging techniques that provide detailed visualization of the abdominal aorta. The most reliable method for diagnosing AAA is CT abdomen and pelvis with IV contrast dye. This imaging modality offers several advantages: it provides high-resolution images, allowing for accurate measurement of the size and extent of the aneurysm and can help determine any involvement of adjacent structures. Additionally, the use of contrast enhances the visualization of blood vessels, making it easier to identify any abnormalities.

While ultrasound imaging is also a common initial screening tool for AAA due to its accessibility and lack of radiation, it does not provide the comprehensive detail that a CT scan with contrast can offer for definitive diagnosis and planning of surgical intervention. Other methods like X-ray or MRI may not be preferred for this condition, as they either lack the specificity needed for vascular assessment or are more complex and costly without providing significant additional benefit in this particular context. Thus, CT imaging remains the gold standard for diagnosing AAA.