Do you order a computed tomography (CT) aortogram rather than a venous or arterial Doppler (ultrasound)?

From the Guidelines

I would typically order a CT aortogram rather than venous or arterial Doppler when evaluating for aortic pathology such as dissection, aneurysm, or rupture. This recommendation is based on the most recent and highest quality study, which emphasizes the importance of CT aortogram in evaluating aortic disease due to its ability to provide detailed cross-sectional images of the aorta and its branches with contrast enhancement 1. CT aortogram allows for visualization of the vessel lumen, wall, and surrounding structures, making it particularly valuable for emergency situations like suspected aortic dissection or rupture where rapid, comprehensive assessment is critical.

Key Benefits of CT Aortogram

• Provides detailed cross-sectional images of the aorta and its branches with contrast enhancement
• Allows for visualization of the vessel lumen, wall, and surrounding structures
• Offers superior spatial resolution compared to Doppler ultrasound
• Can be performed quickly, making it ideal for emergency situations
• Provides information about both the vessel lumen and potential extravascular complications

Limitations of Doppler Ultrasound

• Has significant limitations for aortic imaging due to body habitus, bowel gas, and inability to visualize the entire aorta, especially the thoracic portion
• May not provide sufficient information for preoperative planning in cases of aortic disease

Considerations for CT Aortogram

• Involves radiation exposure, which may be a concern for patients with certain medical conditions
• Requires iodinated contrast, which may be contraindicated in patients with kidney dysfunction or contrast allergies
• Should be used in conjunction with other diagnostic modalities, such as electrocardiogram (ECG)-gated acquisition protocols, to reduce motion artefacts and provide accurate measurements of the aorta 1.

From the Research

Computed Tomography (CT) Aortogram vs Venous or Arterial Doppler (Ultrasound)

• CT aortogram is preferred over venous or arterial Doppler (ultrasound) due to its high sensitivity and specificity in diagnosing aortic diseases, with values greater than 99% for multislice computed tomography (MSCT) in the assessment of aortic dissection 2.
• The use of CT angiography (CTA) has become a standard non-invasive imaging modality for the depiction of vascular anatomy and pathology, with superior diagnostic accuracy to conventional arteriography 3.
• CT aortogram is also less invasive and may be performed in asymptomatic patients undergoing treatment, facilitating the early detection of complications, and can be used for follow-up observation of longstanding aortic diseases 4, 5.
• Recent studies have shown that CT aortography using ultra-low contrast doses can still yield scans of diagnostic quality, reducing the risk of contrast-induced acute kidney injury (CI-AKI) 6.
• The guidelines for acute aortic dissection recommend the use of CT for initial diagnosis, and CT is a primary imaging modality for the diagnosis of aortic diseases due to its minimal invasiveness and agility 5.

Diagnostic Accuracy and Image Quality

• The sensitivity and specificity of MSCT in the assessment of aortic dissection are greater than 99%, and the diagnostic accuracy of CT in detecting inflammatory changes is around 94% 2.
• The quality and speed of CTA examinations have increased dramatically with the evolution of CT technology, making it superior to other imaging modalities 3.
• Studies have shown that CTA using contrast volumes as low as 30 mL can still yield scans of diagnostic quality, and ultra-low contrast doses of 20 mLs (6 g iodine) can produce scans with sufficient quality for diagnosis and planning of surgical intervention 6.

Clinical Applications

• CT aortogram is useful in the diagnosis of aortic dissection, aortic aneurysm, and other aortic diseases, and can be used for follow-up observation and planning of surgical intervention 2, 3, 5.
• The use of CT aortography with ultra-low contrast doses can be beneficial in patients with severe renal insufficiency, reducing the risk of CI-AKI 6.