From the Guidelines
For suspected aortic dissection, you should order a CTA of the chest, abdomen, and pelvis with contrast, as it allows for comprehensive imaging of both the thoracic and abdominal aorta, providing assessment of extension of the dissection along the thoracic, abdominal, and pelvic segments 1. This approach is crucial because aortic dissections can extend throughout the vessel, and limiting imaging to just one segment, such as the chest or abdomen alone, might miss the full extent of the pathology.
- Key benefits of this comprehensive imaging approach include:
- Visualization of the entire aorta from its origin at the heart through the thoracic and abdominal segments down to the iliac bifurcation
- Assessment of the presence of an intimal flap, the true and false lumens, branch vessel involvement, and any complications such as rupture or end-organ ischemia
- Guidance for urgent management decisions, including the need for surgical intervention or endovascular repair
- Optimization of blood pressure control and other supportive measures based on the extent and complications of the dissection The scan should be performed with IV contrast and be ECG-gated if available to minimize motion artifacts from cardiac pulsation, as recommended by the American College of Radiology in their appropriateness criteria for suspected acute aortic syndrome 1.
- Important considerations in the imaging protocol include:
- Use of IV contrast to enhance visualization of the aortic lumen and wall
- ECG-gating to reduce motion artifacts and improve image quality
- Coverage of the entire aorta, from the chest to the pelvis, to ensure detection of the full extent of the dissection Given the critical nature of aortic dissection, with significant implications for morbidity, mortality, and quality of life, it is essential to prioritize comprehensive imaging that can guide timely and effective management 1.
From the Research
Imaging Options for Aortic Dissection
When considering imaging options for aortic dissection, the choice between CTA abdomen aorta & bulat ilio FE and CTA chest PE with contrast depends on various factors.
- The study 2 suggests that a monitored 'aortic dissection screening' protocol that initially images the chest only can significantly reduce contrast and radiation dose without reducing diagnostic accuracy for ED patients who underwent CT for aortic dissection.
- However, the study 3 presents a case where aortic dissection and pulmonary embolism occurred simultaneously, highlighting the importance of considering both conditions in the diagnostic workup.
- The study 4 discusses the use of cardiac CT angiography for patients with acute chest pain and the importance of choosing the most appropriate examination based on the specific clinical situation.
Considerations for Imaging Protocols
When deciding on an imaging protocol, consider the following:
- The study 2 found that aortic dissection CT in the ED is negative in the overwhelming majority of cases, suggesting that a more targeted approach may be sufficient.
- The study 5 found that MRA can be used to guide ED management of suspected acute aortic dissection, particularly in patients with contraindications to CTA.
- The study 6 compared the diagnostic potentialities of TEE, conventional MRI, and contrast-enhanced 3D breath-hold MRA in the post-operative follow-up of dissecting aneurysms, highlighting the importance of considering multiple imaging modalities.
Diagnostic Accuracy and Radiation Exposure
The studies suggest that:
- A monitored 'aortic dissection screening' protocol can reduce radiation dose and contrast volume utilization without compromising diagnostic accuracy 2.
- MRA can be used to guide ED management of suspected acute aortic dissection, particularly in patients with contraindications to CTA 5.
- The choice of imaging protocol should be based on the specific clinical situation and the potential risks and benefits of each modality 4.