Aortic dissection is typically associated with abrupt, severe chest pain which may be associated with loss of one or more peripheral pulses. A small percentage of dissections may be clinically silent and only incidentally detected on chest radiography.

Most dissections arise in the ascending aorta or descending aorta at the level of the aortic isthmus. Pathologically, they are the result of separation of the adventitia and media. Blood may enter the dissection from a tear in the intima and create a false lumen. The underlying cause is usually attributed to degeneration of the media with loss of elastic tissue. The most common abnormality associated with dissection is hypertension, though other systemic disease processes such as Marfan's may be involved. Dissection into branches of the aorta may occur which can limit or occlude flow. Involvement of the aortic valve may result in varying degrees of aortic regurgitation.

Two major classification systems exist to describe the extent of aortic dissection. The Stanford classification divides dissection based upon their involvement of the ascending aorta. A Stanford class A dissection describes involvment of the ascending aorta alone, or dissection involving the ascending and descending aorta. Stanford B dissection involves only the descending aorta.

The DeBakey Type I dissection involves the ascending and descending aorta. Type II involves the ascending aorta only. Type III involves the descending aorta only.

The clinical implication of these classification systems is fairly straightforward. Debakey type III and Stanford type B are typically treated medically, while the remaining classes (those involving the ascending aorta) are typically treated surgically.

Plain film findings may include a widened mediastinum, separation of calcium from the wall of the aortic arch or pleural effusions. Up to one-fifth of patients may have a normal CXR. Angiography, CT and MR are all acceptable methods for further evaluation of suspected dissection. The choice of which exam to use depends on the patients clinical status, contraindications to therapy and clinician preference.