A method of detecting and quantifying severity of myocardial perfusion defects with intravenous ultrasound contrast and breath holding during stress echocardiography.

Abstract

Although breath holding is commonly used to improve and maintain image quality during stress echocardiography, its effects on the qualitative and quantitative analysis of myocardial contrast enhancement (MCE) following intravenously injected microbubbles is unknown. The purpose of this study was to determine how breath holding affects MCE following either an intravenous bolus or continuous infusion of perfluorocarbon containing microbubbles. In 48 patients, intravenous Optison was given at peak dobutamine stress to assess myocardial perfusion. The degree of myocardial opacification was assessed immediately following a breath hold in inspiration (BH(ini)), at the end of a breath hold (BH(term)), and following expiration and a subsequent second breath hold (BH(reinsp)). Pulmonary venous time velocity integrals were recorded during these different phases as well. Eleven patients had quantitative coronary angiography. Mean duration of the breath hold was 7 +/- 1 seconds. Pulmonary venous return fell by 29% +/- 18% at BH(term) (P < 0.001). There was complete disappearance of MCE at BH(term) in 27 of 35 bolus injection patients at peak stress, and no return of MCE following flash destruction during breath holding in 11 of 13 patients receiving continuous infusions. BH(reinsp) resulted in a boluslike return of contrast, with a transient, bright MCE in 44 of 48 patients, and a time intensity plot that resembled a gamma variate function. Perfusion defects were visualized in 25 patients during BH(ini) and 28 patients during BH(reinsp). Coronary artery territory agreement between perfusion assessed during BH(ini) and BH(reinsp) and quantitative coronary angiography was 76% and 81%, respectively.