Two-dimensional quantitative contrast ehocardiography in the assessment of atrial septal defects.

Contrast two-dimensional echocardiograms of the right (RA) and left atria (LA), usingsubcostal, apical, and parasternal views, were compared with the results of cardiac catheterizations in 27 patients with atrial septal defects. Positive-contrast right-to-Ieft shunting (microbubbles moving from RA to LA) was observed in 6 patients, negative-contrast shunting (microbubble-free blood moving from LA to RA) occurred in 8 patients, and bidirectional-contrast shunting in 13 patients. Patients with pulmonary hypertension did not have any negative- or bidirectional-contrast shunting. The same pattern of negative contrast visualization was detected among the different anatomie types of septal defects. Contrast studies were sufficiently sensitive to detect interatrial shunts as smaU as 3-5070of systemic blood flow. Negative-contrast effects within the right atrium, indicative of left-to-right atrial shunts, were quantified by measuring the negative-contrast area and multiplying it by the difference between the video intensity of the negative jet area compared with the surrounding opacified right atrium. The size of these quantitated negative jets (as an area times a change in density) correlated roughly with the pulmonary to systemic flow ratios for the patients evaluated (r =0.75; p < 0.01).A better correlation (r = 0.88; p < 0.001) was obtained when the average sizes of the negative jets in three different views were calcolated. Thus a more precise quantification of three-dimensional shunt flow can be achieved through a videodensitometric analysis of contrast echocardiograms in multiple imaging planes.