BIPLANE TRANSESOPHAGEAL ECHOCARDIOGRAPHY - DIAGNOSTIC IMPROVEMENT VS MONOPLANE TECHNIQUE

Monoplane transesophageal echocardiography (TEE) is a well established diagnostic tool of examination of great value in determining patholog ical changes in both atria, atrioventricular valves, the left-ventricu lar outflow tract, and in the thoracic aorta (Table 1). With the monop lane technique, however, it is never possible to obtain more than para llel, or oblique transverse views of the heart and surrounding vessels . The only means with which to examine anatomic structures in their cr aniocaudal dimension by way of this method is to make a composite of a number of transverse sections. This makes three-dimensional interpret ation of monoplane images difficult. The biplane transesophageal techn ique provides images of orthogonal sections to the transverse plane, a llowing three-dimensional reconstruction and thus greatly improved ins ight into the cardial anatomy. By ante- or retroflection and lateral a ngulation of the probe, it becomes possible to see structures as a who le, the greatest dimension of which may not lie in the strictly sagitt al section, but on a cranio-caudal diagonal plane, e.g. the ascending aorta, or the aortic valve plane. The diagnostic gain of additional da ta through biplane TEE stems from its images of cardial structures, wh ich remain either unsatisfactory or not attainable on monoplane examin ation (Table 2). Above all this pertains to the superior vena cava in its longitudinal extension (Figure 6), the right-ventricular outflow t ract with pulmonary valve, the longitudinal two-chamber view (Figure 3 ), and the CW-Doppler analysis in presence of tricuspid valve regurgit ation (Figure 13). Transversal visualization of the aortic arch is onl y 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 a nd 6), and here in particular the pathology of interatrial septum (Fig ure 7), as well as the aortic valve and the ascending aorta (Figures 8 , 10 and 11). By using the longitudinal imaging plane left atrial appe ndage can be seen without additional anteflection of the probe, thus, reducing stress to the patient during examination. The loss of an infi nite range of planes available to the multiplane technique is a disadv antage, 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 allowsbetter three-dime nsional imaging of anatomic structures and regurgitant jets than do th e mono- and biplane techniques, and comparable data are often only att ained under much longer examination with the biplane instrument. The c linical superiority of multiplane TEE over the biplane transesophageal technique has, however, not as yet been clearly shown.