What is the imaging hallmark of an aortic dissection on CT angiography?

What is the imaging hallmark of an aortic dissection on CT angiography?

• A. Intimal flap with true and false lumen within the aorta.
• B. Aneurysmal dilation without flap.
• C. Calcified plaque along the aorta.
• D. Mural thickening without luminal changes.

Answer: (A)

On CT angiography the key finding of an aortic dissection is an intimal tear that creates two separate blood-filled channels inside the aorta: the true lumen and a false lumen. The intimal flap appears as a thin, linear membrane that separates these two lumens, and contrast typically opacifies the true lumen while the false lumen may fill differently or even become partially thrombosed. This double-lumen sign with a visible flap is what sets dissection apart from other aortic conditions. If you only saw a dilated aorta without a separating flap, or calcified wall plaques, or thickened wall without a new luminal channel, you wouldn’t be seeing a dissection.

On CT angiography the key finding of an aortic dissection is an intimal tear that creates two separate blood-filled channels inside the aorta: the true lumen and a false lumen. The intimal flap appears as a thin, linear membrane that separates these two lumens, and contrast typically opacifies the true lumen while the false lumen may fill differently or even become partially thrombosed. This double-lumen sign with a visible flap is what sets dissection apart from other aortic conditions. If you only saw a dilated aorta without a separating flap, or calcified wall plaques, or thickened wall without a new luminal channel, you wouldn’t be seeing a dissection.