on 10-Dec-2018 (Mon)

The aorta is the largest artery in the body and diseases of the aorta, such as aneurysms, typically remain asymptomatic and undetected until either discovered incidentally on an imaging study or the development of an acute complication. When detected, both thoracic and abdominal aortic aneurysms should be followed carefully on serial imaging studies until large enough to merit intervention.

Various classes of cardiac medications may have salutary effects on the aorta and can be used to reduce stress on the aorta and even improve vascular remodeling. The aorta is also affected by a number of congenital conditions as well as autoimmune vasculitides. For aortic coarctation, please refer to Chap. 21 .

low neutrons, he concluded that he had created new elements; although he was awarded the Nobel Prize for this discovery, the new elements were subsequently revealed to be fission products.

Fermi left Italy in 1938 to escape new Italian racial laws that affected his Jewish wife, Laura Capon. He emigrated to the United States, where he worked on the Manhattan Project during World

The segments of the aorta are differentiated by their anatomic location, size, and branch ■ vessels (Table 11-1 ). Dimensions in males are slightly larger than in females, and the aortic diameters generally increase with age.

war, Fermi served under J. Robert Oppenheimer on the General Advisory Committee, which advised the Atomic Energy Commission on nucle

Imaging modalties of the Aorta

Chest Radiography (CXR)

• CXR has overall limited sensitivity (~30–60 %) for thoracic aortic aneurysm, and
• alone cannot be used to exclude acute or chronic aortopathy
• Calcification or tortuosity of the ascending, arch, and descending thoracic aorta may be visualized, but this is a non-specificific finding in the elderly.
• Opacification of the aortico-pulmonary window, enlargement of the thoracic aorta, increased mediastinal width, displacement of trachea from midline, or obscured/irregular aortic margin may indicate thoracic aortic aneurysm, dissection, or rupture. Displaced intimal calcium and pleural effusion may indicate dissection.

Echocardiography and Ultrasonography
Portable, avoids radiation and contrast media, and can be deployed intra-operatively.

Transthoracic Echocardiography (TTE)

• TTE cannot provide a comprehensive exam of the aorta, but certain regions can be visualized: aortic valve and root, ascending aorta, arch, descending, and abdominal aorta
• TTE is reasonable for assessing aortic valve disorders and monitoring aortic root and ascending aortic dilatation (e.g. especially in Marfan syndrome).
• It is not sensitive enough to rule out thoracic aortic dissection (sensitivity 70 %).

Transesophageal Echocardiography (TEE)

• TEE can visualize the ascending aorta, transverse arch, and entire descending thoracic aorta.
• The distal ascending aorta and proximal aortic arch may be obscured by the trachea.
• TEE, in contrast to other modalities, can provide functional information such as flow–dynamics in true and false lumens, detection of IAo, detection of cardiac tamponade, and assessment of left ventricular function.

Abdominal ultrasonography

• the technique of choice for screening for infrarenal abdominal aortic aneurysm (AAA), but is less accurate as applied to the suprarenal aorta or branch vessels.

Imaging modalties of the Aorta

Computed Tomography (CT)

• CT is a highly accurate, rapid, reproducible, and readily available technique for detecting and sizing aortic aneurysms and for the diagnostic evaluation of suspected aortic dissection.
• CT is also helpful at mapping branch vessels, and for detecting mimics of aortic disease (e.g. pericardial disease, gastrointestinal disease).

Magnetic Resonance (MR)

• Imaging MR is also a highly accurate technique for aortic imaging.
• However, the study time is lengthy and the patient is relatively inaccessible, making this modality unsuitable for acute or unstable patients.
• MR is most often performed with intravenous gadolinium as a contrast agent, but the “black-blood” technique with spin-echo sequences can provide satisfactory images without the need for gadolinium.

Aortography

• Catheter-based aortography is an invasive technique that can demonstrate the full extent of aneurysmal disease and dissection, map branch vessel involvement, and demonstrate the presence of IAo.
• However, aortography is not readily available in most settings, requires an expert physician operator, and requires that potentially unstable patients undergo a prolonged procedure.