From the Guidelines
Abdominal Aortic Aneurysm (AAA) Diagnostic Investigations: The most appropriate diagnostic investigations for AAA include ultrasound, CT, and MRI.
Diagnostic Imaging Options
- Ultrasound is recommended as the initial screening test in patients with suspected AAA, particularly for male patients > 65 years of age 1.
- CT is the preferred modality for evaluating most patients with suspected AAA, due to its wide availability, accuracy, and speed, as well as the extent of anatomic detail it provides 1.
- MRI is a reasonable alternative for initial diagnostic imaging, especially in patients with contraindications to iodinated contrast material 1.
Additional Considerations
- CT angiography is optimal for detailed characterization of the aneurysm and may aid in treatment planning 1.
- MR angiography may be substituted if CT cannot be performed, such as in patients allergic to iodinated contrast material 1.
- Invasive angiography has little role in the diagnosis of AAA and is rarely used due to its invasive nature and lower sensitivity compared to other imaging modalities 1.
- TEE and TTE are alternative imaging modalities that can be used in certain clinical circumstances, such as patients with a history of iodinated contrast reaction or those who are too unstable to travel to the radiology suite 1.
From the Research
Diagnostic Investigations for Abdominal Aortic Aneurysm (AAA)
The diagnostic investigations for AAA include:
- Abdominal ultrasonography: considered the preferred modality for screening due to its cost-effectiveness and lack of exposure to ionizing radiation 2, 3
- Computed Tomography (CT): provides accurate information on the diameter of the aneurysm and involvement of renal and iliac arteries 4
- Magnetic Resonance Imaging (MRI): reliable for evaluating aneurysms, but has limited capability in detecting calcifications 4
- Angiography: useful for diagnosing involvement of renal arteries, but may underestimate the diameter of lesions without peripheral calcifications 4
Imaging Modalities
The choice of imaging modality depends on the clinical presentation and risk factors of the patient.
- Ultrasonography is recommended for screening high-risk patients, such as those with a history of smoking or family history of AAA 2, 3
- CT and MRI are useful for evaluating the size and extent of the aneurysm, as well as involvement of surrounding structures 4
- Angiography may be used in certain cases, such as when endovascular repair is being considered 4
Surveillance and Monitoring
Surveillance of AAA depends on the size and growth rate of the aneurysm.