title: Single-scan rest/stress imaging: validation in a porcine model with18F-Flurpiridaz.
abstract: OBJECTIVE
  18F-labeled myocardial flow agents are becoming available for clinical application but the ∼2 hour half-life of18F complicates their clinical application for rest-stress measurements. The goal of this work is to evaluate in a pig model a single-scan method which provides quantitative rest-stress blood flow in less than 15 minutes.
  
  
  METHODS
  Single-scan rest-stress measurements were made using18F-Flurpiridaz. Nine scans were performed in healthy pigs and seven scans were performed in injured pigs. A two-injection, single-scan protocol was used in which an adenosine infusion was started 4 minutes after the first injection of18F-Flurpiridaz and followed either 3 or 6 minutes later by a second radiotracer injection. In two pigs, microsphere flow measurements were made at rest and during stress. Dynamic images were reoriented into the short axis view, and regions of interest (ROIs) for the 17 myocardial segments were defined in bull's eye fashion. PET data were fitted with MGH2, a kinetic model with time varying kinetic parameters, in which blood flow changes abruptly with the introduction of adenosine. Rest and stress myocardial blood flow (MBF) were estimated simultaneously.
  
  
  RESULTS
  The first 12-14 minutes of rest-stress PET data were fitted in detail by the MGH2 model, yielding MBF measurement with a mean precision of 0.035 ml/min/cc. Mean myocardial blood flow across pigs was 0.61 ± 0.11 mL/min/cc at rest and 1.06 ± 0.19 mL/min/cc at stress in healthy pigs and 0.36 ± 0.20 mL/min/cc at rest and 0.62 ± 0.24 mL/min/cc at stress in the ischemic area. Good agreement was obtained with microsphere flow measurement (slope = 1.061 ± 0.017, intercept = 0.051 ± 0.017, mean difference 0.096 ± 0.18 ml/min/cc).
  
  
  CONCLUSIONS
  Accurate rest and stress blood flow estimation can be obtained in less than 15 min of PET acquisition. The method is practical and easy to implement suggesting the possibility of clinical translation.
authors.affiliation: Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Nicolas J
authors.initials: NJ
authors.lastname: Guehl
authors.affiliation: Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Marc D
authors.initials: MD
authors.lastname: Normandin
authors.affiliation: Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Dustin W
authors.initials: DW
authors.lastname: Wooten
authors.affiliation: Cardiac Arrhythmia Service, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Guy
authors.initials: G
authors.lastname: Rozen
authors.affiliation: Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Arkadiusk
authors.initials: A
authors.lastname: Sitek
authors.affiliation: Cardiac Arrhythmia Service, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Ruskin
authors.affiliation: Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Shoup
authors.affiliation: Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.|Cardiac Arrhythmia Service, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Leon M
authors.initials: LM
authors.lastname: Ptaszek
authors.affiliation: Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Georges
authors.initials: G
authors.lastname: El Fakhri
authors.affiliation: Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. alpert@pet.mgh.harvard.edu.
authors.forename: Nathaniel M
authors.initials: NM
authors.lastname: Alpert
mesh_terms: D000818:Animals; D003326:Coronary Circulation; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011724:Pyridazines; D012146:Rest; D013312:Stress, Physiological; D013552:Swine
chemical_list: C525920:BMS 747158-02; D011724:Pyridazines
keywords: Kinetic modeling; Myocardial blood flow; Positron emission tomography