1020-6 Delineation of Three-Dimensional Geometry of Intracardiac Blood Flow Jets and Proximal Flow Convergence Regions in Patients with Flow Abnormalities by Volume-Rendered Three-Dimensional Echocardiography via Transthoracic Imaging

Volume-rendered three-dimensional echocardiography (3DE) has the capability of not only displaying cardiac structures but also has the potential to depict intracardiac flow jets in a dynamic mode. In this study, we explored the ability of 3DE to provide new information on intracardiac flow disturbances not available from 2D color Doppler. Sequential 2DE images with color Doppler information were acquired using a calibrated rotational scanning method by a transthoracic approach in 34 pts (29 adults and 5 children) with a variety of cardiac disorders. Using a computerized motor coupled to conventional transducers (2 MHz to 5 MHz), 2DE images were collected every 2 degrees over a span of 180 degrees along with ECG and respiratory gating. After digital reformatting, thresholding and adequate segmentation, intracardiac flow jets could be seen in every desired 3DE projection. Flow jet reconstruction was possible in all but 1 pt, yielding a total of 34 jets for review (23 regurgitant jets, 9 stenotic jets and 2 shunts). Central flow jets (n=24) were the easiest to reconstruct and display in a dynamic 3DE mode, providing an immediate appreciation oftheir exact shape and spatial extension. Eccentric jets (n=10) with only partial contact with cavity walls could be reconstructed but required more careful segmentation. However, when the flow jet was in direct contact and alignment with a wall, it was difficult to clearly discriminate the flow data from the tissue signals. When mental 3D appraisal of flow jets (based on combining various 2D color Doppler views) was compared to actual 3DE display of flow jets, there was concordance in all instances of central jets, but when a jet was eccentric, 3DE yielded an easier and frequently different dynamic geometry. Examination of various flow convergence zones (n=10) by 3DE indicated the absence of a perfect hemispheric geometry in all cases (in contrast to the generally-held assumption of a hemisphere in the use of PISA method). We conclude that 3DE has the potential to provide useful information onflow abnormalities in patients, with important diagnostic and research implications on the study of flow and flow quantitation