title: Optimization of dual-saturation single bolus acquisition for quantitative cardiac perfusion and myocardial blood flow maps.
abstract: BACKGROUND
  In-vivo quantification of cardiac perfusion is of great research and clinical value. The dual-bolus strategy is universally used in clinical protocols but has known limitations. The dual-saturation acquisition strategy has been proposed as a more accurate alternative, but has not been validated across the wide range of perfusion rates encountered clinically. Dual-saturation acquisition also lacks a clinically-applicable procedure for optimizing parameter selection. Here we present a comprehensive validation study of dual-saturation strategy in vitro and in vivo.
  
  
  METHODS
  The impact of saturation time and profile ordering in acquisitions was systematically analyzed in a phantom consisting of 15 tubes containing different concentrations of contrast agent. In-vivo experiments in healthy pigs were conducted to evaluate the effect of R2* on the definition of the arterial input function (AIF) and to evaluate the relationship between R2* and R1 variations during first-pass of the contrast agent. Quantification by dual-saturation perfusion was compared with the reference-standard dual-bolus strategy in 11 pigs with different grades of myocardial perfusion.
  
  
  RESULTS
  Adequate flow estimation by the dual-saturation strategy is achieved with myocardial tissue saturation times around 100 ms (always <30 ms of AIF), with the lowest echo time, and following a signal model for contrast conversion that takes into account the residual R2* effect and profile ordering. There was a good correlation and agreement between myocardial perfusion quantitation by dual-saturation and dual-bolus techniques (R(2) = 0.92, mean difference of 0.1 ml/min/g; myocardial perfusion ranges between 0.18 and 3.93 ml/min/g).
  
  
  CONCLUSIONS
  The dual-saturation acquisition strategy produces accurate estimates of absolute myocardial perfusion in vivo. The procedure presented here can be applied with minimal interference in standard clinical procedures.
authors.affiliation: Philips Healthcare Iberia, Maria de Portugal 1. 28050, Madrid, Spain. Javier.Sanchez.Gonzalez@philips.com.
authors.forename: Javier
authors.initials: J
authors.lastname: Sánchez-González
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernandez Almagro 3. 28029, Madrid, Spain. Rodrigo.Fernandez@cnic.es.|Hospital Universitario Clínico San Carlos, Madrid, Spain. Rodrigo.Fernandez@cnic.es.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Fernandez-Jiménez
authors.affiliation: Philips Healthcare Iberia, Maria de Portugal 1. 28050, Madrid, Spain. Nils.Nothnagel@philips.com.
authors.forename: Nils D
authors.initials: ND
authors.lastname: Nothnagel
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernandez Almagro 3. 28029, Madrid, Spain. GonzaloJavier.Lopez@cnic.es.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: López-Martín
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernandez Almagro 3. 28029, Madrid, Spain. Valentin.Fuster@mssm.edu.|The Zena and Michael A. Wiener CVI, Mount Sinai School of Medicine, New York, NY, USA. Valentin.Fuster@mssm.edu.
authors.forename: Valentin
authors.initials: V
authors.lastname: Fuster
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernandez Almagro 3. 28029, Madrid, Spain. BIbanez@cnic.es.|Hospital Universitario Clínico San Carlos, Madrid, Spain. BIbanez@cnic.es.
authors.forename: Borja
authors.initials: B
authors.lastname: Ibañez
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D003287:Contrast Media / Q000008:administration & dosage*; D003326:Coronary Circulation; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D023421:Models, Animal; D008955:Models, Cardiovascular; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D011237:Predictive Value of Tests; D012039:Regional Blood Flow; D013552:Swine; D013997:Time Factors
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA