title: In Search of the Optimal Heart Perfusion Ultrasound Imaging Platform.
abstract: OBJECTIVE
  Quantification of myocardial perfusion by contrast echocardiography remains a challenge. Existing imaging phantoms used to evaluate the performance of ultrasound scanners do not comply with perfusion basics in the myocardium, where perfusion and motion are inherently coupled. To contribute toward an improvement, we developed a contrast echocardiographic perfusion imaging platform based on an isolated rat heart coupled to an ultrasound scanner.
  
  
  METHODS
  Perfusion was assessed by using 3 different types of contrast agents: dextran-based Promiten (Meda AB, Solna, Sweden), phospholipid-shelled SonoVue (Bracco Diagnostics, Inc, Princeton, NJ), and polymer-shelled MB-pH5-RT, developed in-house. The myocardial video intensity was monitored over time from contrast agent administration to peak, and 2 characteristic constants were calculated by using an exponential fit: A, representing capillary volume; and β, representing inflow velocity.
  
  
  RESULTS
  Acquired experimental evidence demonstrates that the application of all 3 contrast agents allows sonographic estimation of myocardial perfusion in the isolated rat heart. Video intensity maps show that an increase in contrast concentration increases the late-plateau values, A, mimicking increased capillary volume. Estimated values of the flow, proportional to A × β, increase when the pressure of the perfusate column increases from 80 to 110 cm of water. This finding is in agreement with the true values of the coronary flow increase measured by a flowmeter attached to the aortic cannula.
  
  
  CONCLUSIONS
  The contrast echocardiographic perfusion imaging platform described holds promise for standardized evaluation and optimization of contrast perfusion ultrasound imaging in which real-time inflow curves at low acoustic power semiquantitatively reflect coronary flow.
authors.affiliation: Departments of Clinical Science, Intervention, and Technology (D.G., B.J.-S.) and Medicine (A.G.), Karolinska Institute, Stockholm, Sweden; Department of Medical Engineering, KTH Royal Institute of Technology, School of Technology and Health, Stockholm, Sweden (D.G., B.J.-S.);and Department of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden (D.G., A.G., B.J.-S). dmitryg@kth.se.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Grishenkov
authors.affiliation: Departments of Clinical Science, Intervention, and Technology (D.G., B.J.-S.) and Medicine (A.G.), Karolinska Institute, Stockholm, Sweden; Department of Medical Engineering, KTH Royal Institute of Technology, School of Technology and Health, Stockholm, Sweden (D.G., B.J.-S.);and Department of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden (D.G., A.G., B.J.-S).
authors.forename: Adrian
authors.initials: A
authors.lastname: Gonon
authors.affiliation: Departments of Clinical Science, Intervention, and Technology (D.G., B.J.-S.) and Medicine (A.G.), Karolinska Institute, Stockholm, Sweden; Department of Medical Engineering, KTH Royal Institute of Technology, School of Technology and Health, Stockholm, Sweden (D.G., B.J.-S.);and Department of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden (D.G., A.G., B.J.-S).
authors.forename: Birgitta
authors.initials: B
authors.lastname: Janerot-Sjoberg
mesh_terms: D000818:Animals; D003287:Contrast Media; D003911:Dextrans; D004452:Echocardiography / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods; D000067268:Isolated Heart Preparation / Q000295:instrumentation* / Q000379:methods; D008297:Male; D055414:Myocardial Perfusion Imaging / Q000295:instrumentation* / Q000379:methods; D010743:Phospholipids; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013459:Sulfur Hexafluoride
chemical_list: D003287:Contrast Media; D003911:Dextrans; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride
keywords: Langendorff; contrast agent; isolated heart; perfusion; vascular ultrasound