Question

This CT of the thorax represents:

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

Hint:

An intimal flap with true and false lumens, located beyond the arch.

Answer 1

The Correct Option is B

Step 1: Look inside the aorta on the contrast CT. A thin linear membrane divides the lumen into two compartments, a true and a false channel. That dividing intimal flap is the signature of a dissection.

Step 2: The mechanism is an intimal tear that lets blood burrow between the aortic wall layers and force them apart, creating the second lumen. CT angiography displays both lumens clearly. Here the flap sits in the descending segment, beyond the arch, so it is a descending (type B) dissection.

Step 3: Rule out the rest. A pure aneurysm shows a dilated aorta but no separating flap. An ascending dissection would carry the flap in the ascending portion. Cystic fibrosis is a pulmonary disorder with bronchiectasis and mucus plugging, unrelated to an aortic flap. The descending intimal flap settles the diagnosis.
\[\boxed{\text{Descending aortic dissection}}\]