HISTORY:38-year-old female with 6 hours of new-onset squeezing chest pain radiating to neck and left arm.

DIAGNOSIS: Acute aortic dissection (Type A)

PERTINENT FINDINGS:

Pre-contrast images:

These are always obtained to exclude mediastinal hematoma or aortic intramural (wall) hematoma which are hyperdense on non-contrast images, and may be missed once contrast has been administered. In this case, no mediastinal hematoma or intramural hemorrhage is seen.

There is aneurysmal dilatation of the ascending thoracic aorta measuring up to 4.9 cm (normal is < 3.5 cm). 

Post-contrast images (arterial phase):

You may need to window the image for better contrast resolution. The BONE windows are best for viewing the intimal flap.

There is a Type A aortic dissection from the aortic root extending through the bifurcation of the common iliac arteries. The dissection flap extends very close to the right coronary cusp, but does not clearly extend into the right coronary artery. There is superior extent of the dissection involving the brachiocephalic/innominate artery, left common carotid, and left subclavian arteries.

The true lumen is usually smaller and anterior to the false lumen.

There is inferior extension of the dissection flap to the right common iliac artery and left common iliac artery to the left internal iliac artery

The celiac artery arises from the true lumen. The dissection flap extends into superior mesenteric artery (SMA) which arises from both the true and false lumen. The IMA arises from the true lumen.

The left renal artery arises from the true lumen. The right renal artery arises from the false lumen. There is an accessory right renal artery arising from the true lumen.

Now look back at the pre-contrast images. Notice how the intimal flap is not clearly seen on these images.

OTHER FINDINGS:

There is an osteochondroma arising from the right seventh posterior rib.

KEY POINTS:

• Aortic dissection is the most common form of the acute aortic syndromes. It occurs when blood enters the medial layer of the aortic wall through a tear or penetrating ulcer in the intima and tracks along the media, forming a second blood-filled channel within the wall.
• Primarily occurs in elderly patients with hypertension
• Additional risk factors include patients with structural aortic abnormalities (bicuspid aortic valve, aortic coarctation), connective tissue diseases (Marfan syndrome, Ehlers-Danlos syndrome), Turners syndrome, and pregnancy.

Classifications: 

• Stanford: type A and B
• DeBakey: Type I and II
• Stanford type B is usually treated medically with aggressive blood control management. Stanford Type A or complicated type B is treated surgically.