title: Quantitative echocardiographic evaluation of myocardial perfusion using interrupted contrast infusion technique: in vivo validation studies and feasibility in human beings.
abstract: BACKGROUND
  We recently developed a new approach for contrast echocardiographic quantification of myocardial perfusion, based on brief interruptions of contrast infusion, which was designed to overcome the limitations of existing techniques. In this study, our technique was initially validated in a series of animal experiments designed to detect regional perfusion variations in vivo. Subsequently, clinical feasibility of perfusion measurements was tested.
  
  
  METHODS
  Regional perfusion was measured transthoracically in 6 anesthetized pigs during baseline, partial left anterior descending coronary artery occlusion, and reperfusion, and validated with fluorescent microspheres. Adenosine-induced changes in perfusion were measured in 8 healthy volunteers. In both protocols, imaging was optimized during contrast infusion (Definity). Infusion was interrupted to allow contrast clearance and images were acquired during subsequent contrast inflow. Myocardial videointensity was measured over time and peak contrast inflow rate was calculated.
  
  
  RESULTS
  In pigs, partial coronary occlusion resulted in a 47 +/- 23% decrease in peak contrast inflow rate in the left anterior descending coronary artery perfusion territory (P < .05), which was reversed during reperfusion, without concomitant decrease in other perfusion territories. These changes were in agreement with microspheres. In human beings, adenosine increased peak contrast inflow rate to 278 +/- 123% of baseline (P < .05).
  
  
  CONCLUSIONS
  The interruption of contrast infusion technique is a sensitive tool for accurate quantification of myocardial perfusion, which may constitute an alternative to currently used techniques.
authors.affiliation: Department of Medicine, University of Chicago, Chicago, Illinois, USA.
authors.forename: Eran
authors.initials: E
authors.lastname: Toledo
authors.forename: Roberto M
authors.initials: RM
authors.lastname: Lang
authors.forename: Keith A
authors.initials: KA
authors.lastname: Collins
authors.forename: Georgeanne
authors.initials: G
authors.lastname: Lammertin
authors.forename: Lynn
authors.initials: L
authors.lastname: Weinert
authors.forename: Victor
authors.initials: V
authors.lastname: Mor-Avi
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D003326:Coronary Circulation; D003974:Diatrizoate Meglumine / Q000008:administration & dosage; D004452:Echocardiography / Q000379:methods*; D005240:Feasibility Studies; D005466:Fluorocarbons / Q000008:administration & dosage*; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007263:Infusions, Parenteral; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine
chemical_list: D003287:Contrast Media; D005466:Fluorocarbons; D003974:Diatrizoate Meglumine; C042852:perflutren