Question

CT of thorax represents:

• A. Ascending aortic dissection
• B. Descending aortic dissection
• C. Aortic aneurysm
• D. Cystic fibrosis

Hint:

Intimal flap with true and false lumen limited to the descending thoracic aorta.

Answer 1

The Correct Option is B

Step 1: The contrast CT of the thorax shows an intimal flap separating a true and a false lumen within the descending thoracic aorta only, sparing the ascending aorta. This is a descending (Stanford type B) aortic dissection.
Step 2: Aortic dissection results from degeneration of the thoracic aortic wall, most often in middle-aged men, classically presenting as sudden razor-sharp interscapular pain. The CT hallmark is the true and false lumen with an intervening flap.
Step 3: By the Stanford classification, type A involves the ascending aorta/arch and needs urgent surgery, whereas type B involves only the descending aorta and is generally managed conservatively. A flap limited to the descending aorta indicates type B.
Step 4: Why not the others - an ascending dissection would show the flap in the ascending aorta; a simple aortic aneurysm shows luminal dilatation without a dissecting flap; cystic fibrosis affects the lungs (bronchiectasis), not the aorta. The descending-only intimal flap confirms descending aortic dissection.