A comparison of video and digital data in the assessment of myocardial perfusion abnormalities by myocardial contrast echocardiography

Objective: The objective of the present study was to compare the digital and video data of myocardial contrast echocardiography (MCE) to assess altered myocardial blood flow produced by graded coronary stenoses. Methods: Three grades of left anterior descending (LAD) coronary artery stenosis and occlusion were created in eight open-chest canine models. MCE was performed with BR1 infusion by harmonic power Doppler with ECG gated intermittent triggered imaging at pulsing intervals ranging from 1:1 to 1:10. For images that were recorded simultaneously on both a videotape (video data) and an optical disk (digital data), myocardial signal intensity in the LAD region was plotted vs. pulsing intervals and was fitted to an exponential function:y=A(1 − e^−bt), where A is the peak plateau signal intensity, and b is the rate of signal intensity rise for quantification of myocardial blood flow. Results: Both values for A and b progressively decreased with a greater level of stenosis. The correlation of A with myocardial blood flow (determined by use of fluorescent microspheres) was weak with digital data (r= 0.38, p= 0.037), and was insignificant with video data (r= 0.16, p= 0.38). The correlation of b with microsphere-derived myocardial blood flow was better than that of A with both video and digital data, and was similar between the two kinds of data (video:r= 0.69, p < 0.0001; digital:r= 0.68, p < 0.0001). Conclusions: Video and digital MCE data are equivalent in their ability to quantify altered myocardial blood flow produced by graded coronary stenoses.