Echocardiography of the aortic root.

The anterior and posterior walls of the aortic root are recognized as a pair of parallel linear signals which move anteriorly in systole and posteriorly in diastole. Valve cusps appear as thin lines which move briskly toward the periphery of the aortic lumen in systole and coapt in the middle in diastole producing a box-like configuration. Cusp calcification results in the appearance of multiple, linear echoes within the aortic root. Mild aortic stenosis is characterized by lightly calcified leaflets whereas heavy calcification, which completely obscures cusp motion, signifies severe stenosis. Aortic aneurysms produce significant enlargement of the aortic root image; marked widening of the aortic walls indicates the presence of aortic root dissection, but there are important limitations and pitfalls in the diagnosis of this condition. A markedly eccentric diastolic cusp position within the aortic lumen resulting in asymmetric images of the leaflets in systole is the hallmark of a bicuspid aortic valve. An abrupt premature closure of the valve leaflets in early systole is typical of subaortic membranous stenosis. In tetralogy of Fallot the aortic root is dilated and overrides the ventricular septum.