[Biplane transesophageal echocardiography. Diagnostic improvement over the mono-plane technique]

Monoplane transesophageal echocardiography (TEE) is a well established diagnostic tool of examination of great value in determining pathological changes in both atria, atrioventricular valves, the left-ventricular outflow tract, and in the thoracic aorta (Table 1). With the monoplane technique, however, it is never possible to obtain more than parallel, or oblique transverse views of the heart and surrounding vessels. The only means with which to examine anatomic structures in their cranio-caudal dimension by way of this method is to make a composite of a number of transverse sections. This makes three-dimensional interpretation of monoplane images difficult. The biplane transesophageal technique provides images of orthogonal sections to the transverse plane, allowing three-dimensional reconstruction and thus greatly improved insight into the cardial anatomy. By ante- or retroflection and lateral angulation of the probe, it becomes possible to see structures as a whole, the greatest dimension of which may not lie in the strictly sagittal section, but on a craniocaudal diagonal plane, e.g. the ascending aorta, or the aortic valve plane. The diagnostic gain of additional data through biplane TEE stems from its images of cardial structures, which remain either unsatisfactory or not attainable on monoplane examination (Table 2). Above all this pertains to the superior vena cava in its longitudinal extension (Figure 6), the right-ventricular outflow tract with pulmonary valve, the longitudinal two-chamber view (Figure 3), and the CW-Doppler analysis in presence of tricuspid valve regurgitation (Figure 13). Transversal visualization of the aortic arch is only feasible by using biplane imaging technique (Figure 12). Compared to the monoplane technique, it shows clearly more distinct views of the apex of the left ventricle (Figure 1), the atrial anatomy (Figures 5 and 6), and here in particular the pathology of interatrial septum (Figure 7), as well as the aortic valve and the ascending aorta (Figures 8, 10 and 11). By using the longitudinal imaging plane left atrial appendage can be seen without additional anteflection of the probe, thus, reducing stress to the patient during examination. The loss of an infinite range of planes available to the multiplane technique is a disadvantage, but this can usually be compensated by appropriate flecting of the probe and adequate simultaneous lateral angulation. The range of rotation of the probe in the multiplane method allows better three-dimensional imaging of anatomic structures and regurgitant jets than do the mono- and biplane techniques, and comparable data are often only attained under much longer examination with the biplane instrument.(ABSTRACT TRUNCATED AT 400 WORDS)