Imaging and Quantification of Myocardial Perfusion Using Real-Time Three-Dimensional Echocardiography

Imaging and Quantification of Myocardial Perfusion Using Real-Time Three-Dimensional Echocardiography Eran Toledo, Roberto M. Lang, Keith A. Collins, Georgeanne Lammertin, Ursula Williams, Lynn Weinert, Gil Bolotin, Patrick D. Coon, Jai Raman, Lawrence D. Jacobs, Victor Mor-Avi We tested the feasibility of real-time three-dimensional echocardiographic (RT3DE) imaging and volumetric analysis of myocardial perfusion. In three protocols, administration of contrast resulted in visible and quantifiable changes in myocardial video-intensity (MVI), which was measured over time in three-dimensional slices to calculate peak contrast inflow rate (PCIR). In nine isolated rabbit hearts, PCIR progressively decreased with coronary flow. In five pigs, partial left anterior descending artery occlusion caused a 59 ± 26% decrease in PCIR exclusively in the left anterior descending artery territory, in agreement with microspheres. In eight normal volunteers, adenosine infusion increased PCIR to 198 ± 57% of baseline. Contrast-enhanced RT3DE imaging allows volumetric quantification of myocardial perfusion. We tested the feasibility of real-time three-dimensional echocardiographic (RT3DE) perfusion imaging and developed and validated an algorithm for volumetric analysis of myocardial contrast inflow. The study included three protocols wherein perfusion was measured: 1) in an ex-vivo model of controlled global coronary flow, 2) in an in-vivo model during regional perfusion variations, and 3) in humans during pharmacologically induced hyperemia. The RT3DE technology offers an opportunity for myocardial perfusion imaging without multi-slice reconstruction and repeated contrast maneuvers. Electrocardiographically triggered harmonic RT3DE datasets were acquired (Philips 7500) while infusion of Definity was initiated and reached a steady state. Protocol 1 was performed in nine isolated rabbit hearts and included three coronary flow levels. In protocol 2, changes in regional perfusion caused by partial left anterior descending artery occlusion were measured in five pigs. In protocol 3, adenosine-induced changes in perfusion were measured in eight normal volunteers. Myocardial video-intensity (MVI) was measured over time in three-dimensional (3D) slices to calculate peak contrast inflow rate (PCIR). In pigs, PCIR was measured on a regional basis and validated against microspheres. The RT3DE imaging allowed selection of slices for perfusion analysis in rabbit hearts, pigs, and humans.