Real-time three-dimensional myocardial contrast echocardiography in assessment of myocardial perfusion defects

Both real-time three-dimensional echocardiography (RT3DE) and myocardial contrast echocardiography (MCE) are novel imaging techniques. The purpose of this study was to confirm the feasibility and accuracy of RT3DE combined with MCE for quantitative evaluation of myocardial perfusion defects.

Thirteen dogs underwent ligation of the left anterior descending artery (LAD, n = 6) or distal branch of the left circumflex artery (LCX, n = 7) under general anaesthesia. Three to four ml of a perfluoropropane (C3F8) microbubble contrast agent was injected intravenously to assess the resulting myocardial perfusion defects with a commercially available Philips SONOS-7500 ultrasound system. After removal of the dog hearts, Evans blue dye was injected via the left and right coronary arteries to stain the myocardium at risk. In vitro anatomic measurements of myocardial mass after removal of the animals' hearts were used as controls.

Left ventricular (LV) mass determined by RT3DE ranged 36.7 - 68.9 g [mean, (54.6 +/- 9.6) g] before coronary artery ligation, and correlated highly (r = 0.99) with in vitro measurement of LV mass [range, 38.9 - 71.1 g; mean, (55.6 +/- 9.3) g]. There was no significant difference between RT3DE and in vitro measurements of LV mass [range, 36.7 - 68.9 g; mean, (51.3 +/- 12.5) g. Or range, 38.9 - 71.1 g; mean, (53.7 +/- 12.3) g, respectively] and under-perfused mass [range, 0 - 21.4 g; mean, (12.0 +/- 6.9) g. Or range, 0 - 19.8 g; mean, (10.8 +/- 6.3) g, respectively] after the LAD ligation (P > 0.05). Likewise, no significant difference was present between RT3DE and in vitro measurements of LV mass [range, 50.1 - 65.4 g; mean, (57.5 +/- 5.9) g. Or range, 51.5 - 65.8 g; mean, (57.3 +/- 6.4) g, respectively] and under-perfused mass [range, 0 - 25.6 g; mean, (13.3 +/- 9.6) g. Or range, 0 - 22.7 g; mean, (12.8 +/- 8.1) g, respectively] after the LCX ligation (P > 0.05). For all the animals with coronary ligation, LV mass measured by RT3DE ranged 35.9 - 68.6 g [mean, (54.8 +/- 10.0) g] and there was no significant difference between RT3DE and in vitro measurements of LV mass and under-perfused mass (P > 0.05, r = 0.99). Further, the under-perfused mass derived from RT3DE [range, 0 - 25.6 g; mean, (12.7 +/- 8.2) g] correlated strongly with the in vitro measurements [range, 0 - 22.7 g; mean, (11.9 +/- 7.2) g] (r = 0.96).

RT3DE with MCE is a rapid and accurate method for estimating LV myocardial mass and quantifying perfusion defects.