The Aortic Valve and the Aorta

Abstract

Unlike imaging of the mitral valve, real-time 3D TEE has some limitations in imaging the aortic valve leaflets. There are many reasons for this. First, the aortic valve is anterior to the mitral valve and therefore further from the transducer. Second, the aortic leaflets are thinner than the mitral leaflets. Third, the aortic plane is oblique to the ultrasound beams. Because of these factors, the machine settings are less effective in differentiating aortic leaflets from the background noise. In addition, in a closed position, the body of the leaflets is nearly parallel to the ultrasound beams, resulting in feeble echoes (most are scattering echoes rather than specular echoes). When the gain is adjusted to remove noise, most of the echoes from the leaflet tissue also disappear, leaving mainly “drop-out artifacts.” The drop-out artifacts are less evident in systole because when the leaflets are in the open position, they become nearly perpendicular to the ultrasound beams (Figs. 4.1 and 4.2). Overall, it is hardly surprising that aortic leaflets cannot usually be visualized in their entirety with real-time 3D TEE. Despite these difficulties, in some patients we were able to create good images of the aortic leaflets in both diastole and systole. We use these patients for describing the following normal features of the aortic valve and the aortic root (see also Movies 4.1 and 4.2).