DETECTION OF MYOCARDIAL PERFUSION IN MULTIPLE ECHOCARDIOGRAPHIC WINDOWS WITH ONE INTRAVENOUS-INJECTION OF MICROBUBBLES USING TRANSIENT-RESPONSE 2ND-HARMONIC IMAGING

Objectives. The purpose of this study was to prove that transient resp onse harmonic imaging could detect normal and abnormal myocardial perf usion in multiple echocardiographic windows with one intravenous injec tion of microbubbles in humans. Background. Myocardial ultrasound cont rast can be produced from intravenous perfluorocarbon-exposed sonicate d dextrose albumin, and ultrasound can be significantly improved by br iefly suspending the interval between frame rates, Whether this contra st can noninvasively quantify myocardial perfusion in humans is unknow n. Methods. In 28 patients, harmonic transient response imaging was us ed to image the heart in multiple different imaging planes after one i ntravenous injection of ultrasound contrast agent. Twenty-five of thes e 28 patients had a repeat injection during dipyridamole stress. In th e primary view, the ultrasound transmission rate was one frame per car diac cycle; in secondary and tertiary views, the transmission rate was once every multiple cardiac cycles. Regional myocardial contrast was visually assessed and quantified off-line. Quantitative rest thallium and dipyridamole stress sestamibi imaging was also performed, Results. Perfusion abnormalities were evident in the secondary and tertiary vi ews only with one frame every multiple cardiac cycles. Regional peak m yocardial videointensity (PMVI) correlated closely with regional trace r uptake in individual patients both at rest (r = 0.84) and during str ess (r = 0.88). A PMVI ratio (abnormal region divided by the region wi th highest nuclear uptake) <0.6 in any view had a 92% sensitivity and a 83% specificity in identifying a regional nuclear perfusion abnormal ity. Conclusions. Transient response imaging produces myocardial contr ast in multiple views with one intravenous injection of contrast agent and can accurately identify regional myocardial perfusion abnormaliti es. (C) 1997 by the American College of Cardiology.