title: Residual Activity Correction in Quantitative Myocardial Perfusion13N-Ammonia PET Imaging: A Study in Post-MI Patients.
abstract: Positron emission tomography (PET) is the gold standard for the quantification of myocardial blood flow (MBF). A standard PET scan is acquired in two phases (rest and pharmacological stress).13N-ammonia is a perfusion radiotracer that may show residual activity, which may affect MBF estimation during the second phase of the scan. An algorithm for residual activity correction (RAC) is available when reconstruction is performed using Syngo MBF (by Siemens). The aim of this study was to evaluate differences in MBF estimation with and without RAC by Syngo MBF in patients with a previous MI using13N-ammonia PET.
  
  
  METHODS
  MBF was evaluated by13N-ammonia PET in a group of 25 patients with a history of MI. Dynamic MBF measurements were analyzed with Syngo Dynamic PET, with and without RAC, and the results were evaluated with statistical methods.
  
  
  RESULTS
  Significant differences in stress phase MBF after RAC were identified in the left anterior descending coronary artery (LAD) territory (p=0.0425) and the right coronary artery (RCA) territory (p=0.004). A trend towards significance was identified in the global polar plot (p=0.049). No statistically significant difference was found in the left circumflex artery (LCx) territory (p=0.333).
  
  
  CONCLUSIONS
  Syngo Dynamic PET, through its RAC function, can be a useful adjunct in assessing second-phase MBF of primarily the RCA territory and secondarily the global polar plot and LAD territory but not the LCx territory.
authors.affiliation: Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: georgemm32@gmail.com.
authors.forename: George
authors.initials: G
authors.lastname: Markousis-Mavrogenis
authors.affiliation: Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Luis Eduardo
authors.initials: LE
authors.lastname: Juárez-Orozco
authors.affiliation: Department of Physiology, National Autonomous University of Mexico, Mexico City, Mexico.
authors.forename: Erick
authors.initials: E
authors.lastname: Alexanderson
mesh_terms: D000368:Aged; D000641:Ammonia / Q000008:administration & dosage* / Q000378:metabolism; D001783:Blood Flow Velocity / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009590:Nitrogen Radioisotopes / Q000378:metabolism; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies
chemical_list: D009590:Nitrogen Radioisotopes; D019275:Radiopharmaceuticals; D000641:Ammonia
keywords: Coronary arteries; Myocardial perfusion; PET; Residual activity correction; Syngo Dynamic PET