TRANSTHORACIC REAL-TIME 3-DIMENSIONAL ECHOCARDIOGRAPHY USING A FAN-LIKE SCANNING APPROACH FOR DATA-ACQUISITION - METHODS, STRENGTHS, PROBLEMS, AND INITIAL CLINICAL-EXPERIENCE

Three-dimensional echocardiography is an emerging clinical method to a ssess cardiovascular disorders. The feasibility of using a linear mode scanning (parallel slicing) for transthoracic data acquisition has be en demonstrated. In this study, we evaluated the feasibility of real-t ime transthoracic three-dimensional imaging of the heart using a fan-l ike scanning mode of echocardiographic data acquisition. We used a com puter-driven motor to sequentially angulate transthoracic transducers over a fan-like arc up to 90-degrees. With careful ECG and respiratory gating, we acquired basic two-dimensional data set via parasternal an d subcostal windows and performed dynamic three-dimensional reconstruc tions. The problems encountered included the need to repeat data acqui sition sequences because of transducer movement or inappropriate gain and gray scale settings. From 15 scanning sequences in four patients, we were able to use ten sets of data. These yielded good quality three -dimensional studies projecting normal valves, a stenotic mitral valve , and an atrial septal defect, in a number of novel views. The valves could be visualized from above and from below as well as in other orie ntations, and the detailed anatomy appraised. Spatial relationships of the atrial septal defect with inferior and superior vena cava, corona ry sinus, or tricuspid annulus could be uniquely displayed through vie ws from the right side of the heart. This technique provided adequate new imaging planes not available from two-dimensional echocardiography . This experience demonstrates for the first time that transthoracic t hree-dimensional echocardiography using a fan-like scanning mode of da ta acquisition is feasible, and that it provides adequate visualizatio n of intracardiac structures in unique projections. This article prese nts the first clinical experience with this approach. Further developm ents of this technique could propel three-dimensional echocardiography in day-to-day clinical practice.