Chapter30 Aorta

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Section V: Cardiac Radiology

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Figure 30.24.  Diffuse Thoracic Aortic Atherosclerotic Disease. Frontal ( A ) and lateral ( B ) chest radiographs in a 95-year-old man demonstrate multifocal calcified plaques ( arrowheads ) along the thoracic aorta. The patient has had prior coronary artery bypass grafting indicated by the surgical clips ( arrows ) and transcatheter aortic valve intervention (TAVI, *). Sagittal nonenhanced chest CT in a different patient ( C ), a 79-year- old man, demonstrates multifocal calcifications along the descending aorta.

course of the aorta (Fig. 30.24). On chest CT, aortic athero- sclerotic disease is a common finding and does not usually lead to direct hemodynamic compromise, given the large cali- ber of the aorta. However, given that atherosclerotic disease is a multifocal process, in the thorax there may be concomitant disease involving the subclavian or carotid arteries which can lead to hemodynamic compromise. In some patients with severe atherosclerotic disease, thick layers of diffuse, predominantly noncalcified atherosclerotic plaques can layer much of the thoracic and abdominal aorta, which has been termed as “complex atheroma” by some authors (Fig. 30.25). These complex atheromas, which are an indirect sign of previous plaque rupture, are independent risk factors for the development of future ischemic events and should be mentioned as they may change medical or surgical management. In certain areas, contrast can be seen extending between areas of complex plaque, toward the wall of the aorta, which some authors refer to as “plaque ulceration.” This appearance can mimic a penetrating atherosclerotic ulcer (PAU), which is

discussed in more detail below, but the distinction between the two is imperative. While plaque ulceration is an indirect sign of previous plaque rupture and can lead to thromboem- bolic events, a PAU is a sign of intimal disruption and lies in the “acute aortic syndrome” spectrum, which is also discussed below. In general, ulcerated plaque will not extend beyond the lumen of the aorta into the intima which is demarcated in areas by linear calcification due to atherosclerosis (Fig. 30.26). However, distinction between the two is not always easy, even among expert radiologists.

Aneurysm Sinus of Valsalva Aneurysm

Sinus of Valsalva aneurysms are abnormal dilations of the sinuses which can be congenital or acquired. Congenital aneu- rysm secondary to weakness in the fibroelastic elements is seen in connective tissue disorders such as Marfan, Ehlers–Danlos,

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Figure 30.25.  Complex Atherosclerotic Plaque in a Patient With Aneurysmal Dilation of the Aorta. Frontal ( A ) and lateral ( B ) chest radiographs in a 75-year-old woman demonstrate aneurysmal dilation of the ascending aorta ( yellow arrow ), aortic arch ( black arrowheads ), and descending thoracic aorta ( black arrows ). CT angiography at the level of the left pulmonary artery ( C ) shows aneurysmal dilation of the ascending ( A ) and descending ( D ) thoracic aorta. At the level of the aortic arch ( D ), the aortic aneurysm measures up to 5.8 cm. Layering mural thrombus (*) is pres- ent along the arch and descending thoracic aorta and should not be confused with intramural hematoma.