Chest Teaching File

Aortic Dissection

The diagnosis of acute aortic dissection can be difficult only because it requires a high degree of clinical suspicion. It is a diagnosis that can be made using several different modalities.

Computed Tomography

Contrast enhanced CT through the mediastinum demonstrates low attenuation linear structures present within both the ascending and descending aorta. These represent the displaced intima in a patient with a Type A dissection.

Angiography

The differential velocity of blood flow through the true and false lumen helps to identify an aortic dissection. In this aortagram, there is decreased flow within the false lumen compared to the true lumen. The aortic arch branches are connected to the true lumen. The intima can be seen as a thin lucency between the two lumens in the ascending aorta.

Magnetic Resonance Imaging

MRI will also readily demonstrate the displaced intima. The differential flow in the true and false lumen is indicated by the difference in signal intensity in this gradient echo image.

Transeophageal Echocardiography

TEE is yet another way to investigate for aortic dissection. The intima is seen as a thin echogenic line within the aortic lumen. In this image, color Doppler shows jets of blood passing through small holes in the intima.

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