Which imaging modality helps differentiate ACS from aortic dissection in chest pain with suspected dissection?

• A. CT angiography of the chest
• B. Chest X-ray
• C. Bedside echocardiography
• D. Nuclear stress test

Answer: (A)

When chest pain raises suspicion for dissection, you need an imaging study that directly visualizes the aorta to distinguish it from acute coronary syndrome. CT angiography of the chest provides rapid, high-resolution images showing the aortic wall, the presence of an intimal flap, and the true and false lumens, along with which branches are involved. This lets you confirm or rule out dissection quickly and accurately, guiding urgent management and avoiding dangerous choices like anticoagulation if a dissection is present.

Other options don’t fit as well. Chest X-ray might hint at mediastinal widening, but it’s not reliable for diagnosing dissection and can be normal early on. Bedside echocardiography can detect dissection when it involves the ascending aorta and can identify some complications, but it has limited views of the distal aorta and operator dependence, so it isn’t definitive for all dissections. A nuclear stress test is used to assess myocardial perfusion for suspected ACS, but it does not diagnose dissection and delays the appropriate therapy.