REPRODUCIBILITY OF MYOCARDIAL CONTRAST ECHOCARDIOGRAPHY IN HUMAN STUDIES

Experimental and clinical studies were performed to assess the ability of myocardial contrast echocardiography for quantitation of regional myocardial blood flow. To evaluate whether myocardial contrast echocar diography is a reproducible technique in humans, 18 nonselected patien ts undergoing coronary angiography were studied. A total of 107 intrac oronary injections into either the left or the right coronary artery w ere analyzed by computer assisted videodensitometry for peak intensity , contrast decay half-time, and area under the curve. By means of thes e parameters intraobserver, interobserver, and interinjection variabil ity were determined. Intraobserver measurements showed lowest variabil ity with correlation coefficients of 0.83 for contrast decay half-time , 0.93 for peak intensity, and 0.95 for area under the curve. Mean per cent error varied between 6.8% (peak intensity) and 112% (area under t he curve). The correlation coefficients for interobserver variability ranged from 0. 73 for area under the curve to 0.97 for peak intensity. Mean percent error revealed a range between 7.5% for peak intensity a nd 19% for area under the curve. For interinjection variability, the c orrelation coefficient for contrast decay half-time was lower (0.56) t han for peak intensity (0. 73) and area under the curve (0.84). Mean p ercent error were higher than for intraobserver and interobserver vari ability (range 24.1% to 34.2%). Thus, intraobserver and interobserver variability for parameters derived from time-intensity curves after in tracoronary injection of echo contrast agent in humans are sufficient and comparable to data from animal studies. Interinjection variability , however, showed a higher mean percent error. These interinjection di fferences have to be taken into account, if comparative measurements b efore and after interventions are performed.