What is the test of choice for diagnosing an aortic aneurysm?

The test of choice for diagnosing an aortic aneurysm is a CT scan. A CT scan provides detailed and high-resolution images of the aorta and is able to identify the presence, size, and extent of an aneurysm effectively. It helps in evaluating the entire thoracic and abdominal aorta, which is crucial for proper diagnosis and treatment planning.

While ultrasound is a valuable tool, particularly for detecting abdominal aortic aneurysms in asymptomatic patients, it is not as definitive for assessing the full extent of the aneurysm or for thoracic aortic aneurysms, compared to a CT scan. MRI is also useful in some cases but is less commonly used for the initial diagnosis of aortic aneurysms due to availability and longer examination times. X-rays are not typically used for diagnosing aortic aneurysms, as they do not provide sufficient detail to visualize the aorta adequately.

Therefore, the CT scan stands out as the most reliable method for accurately diagnosing an aortic aneurysm and guiding further management.