Mid-esophageal level : From the ME four-chamber view, rotating the probe clockwise to center the tricuspid valve in the imaging plane, permits visualization of the septal leaflet (arising from the septum) and typically the anterior leaflet (adjacent to the right atrial appendage); simultaneous biplane imaging may help clarify which leaflet is imaged since the anterior leaflet is typically seen adjacent to the aorta (Fig. 6.1a). Because the lower right heart border is close to the diaphragm, slow insertion brings the TOE probe to the distal esophagus, brings the probe closer to the tricuspid annulus; frequently there is no left atrium seen, and only the right atrium and coronary sinus with the orthogonal view imaging the right ventricular outflow tract (Fig. 6.1b). This view may also align the Doppler beam with the regurgitant jet and allow a comprehensive evaluation of tricuspid valve function, including an assessment of tricuspid regurgitation severity. Acquiring 3D volumes of the tricuspid valve from this view, may allow live-3D imaging of the surgical view (Fig. 6.2).

Transgastric level : Advancing the TEE probe into the stomach results in the transgastric views. Using a right flexion and rotating the probe to center the tricuspid valve in the imaging plane, results in the inflow-outflow view of the right heart (Fig. 6.3a). The orthogonal view shows all three tricuspid valve leaflets which can also be imaged using a single plane view between 60 and 90 degrees (Fig. 6.3b). This view may be particularly useful intra-procedurally to identify the leaflets and commissures. And using this view as the primary image, a sweep of the entire tricuspid valve orifice could be imaged using simultaneous multiplane imaging. Advancing the TOE probe further into the stomach along with rightward anterior flexion produces a deep transgastric view of the tricuspid valve (Fig. 6.3c), which may also align the insonation beam with the flow across the tricuspid valve, and should be used to assess tricuspid valve function.

Three-dimensional (3D) Echocardiography : 3D echocardiography has significantly improved the accuracy of imaging and identification of the tricuspid leaflets and associated anatomic components of the tricuspid valve complex and obviates the need for mental reconstruction of multiple 2D planes [5]. Lang et al. [6] has suggested standardized imaging display (Fig. 6.2) for the en face view of the tricuspid valve with the interatrial septum placed inferiorly (at the 6 o’clock position) regardless of the atrial or ventricular orientation. The current 3D systems have different resolution for each of the 3 dimensions with axial resolution (~0.5 mm) better than lateral (~2.5 mm) and elevational resolution (~3 mm) [5]. Similar to 2D imaging however, images in the far field may be subject to beam widening and attenuation. When creating 3D images, keeping these current equipment limitations in mind will help determine the best imaging plane for imaging a specific abnormality. The best imaging plane for the tricuspid valve leaflets in systole (closed leaflets) may be the esophageal views since the closed leaflets are perpendicular to the insonation beam, however the diastolic (open) leaflets may be poorly imaged. Conversely, transgastric views may allow imaging of the diastolic leaflets since they will be perpendicular to the insonation beam, but leaflet definition may not be optimal in systole. Obtaining multiple 3D volumes from different views may still be necessary to fully characterize the valve and annulus. Finally, because of the complex nature of the valve, the volume acquired may need to have adjacent structures to help identify leaflet anatomy; the aortic valve/aorta to identify the anterior leaflet, and the interatrial septum/mitral valve to identify the septal leaflet.