title: Use of gated 13N-NH3 micro-PET to examine left ventricular function in rats.
abstract: BACKGROUND
  Myocardial perfusion gating techniques offer the possibility of measurement of left ventricular end-systolic (ESV) and end-diastolic volume (EDV) and left ventricular ejection fraction (LVEF) in clinical and preclinical trials. The aim of this study was to evaluate left ventricular volumes (LVV) and LVEF with 13N-NH3 in comparison with the reference 18F-FDG in different rat models.
  
  
  METHODS
  In this study, 18 male Wistar rats, 12 control rats and 6 rats with myocardial infarction (MI) were imaged with micro-PET. The ratswere scanned with gated 13N-NH3 and 18F-FDG sequentially for the assessment of LVV and LVEF. A validated three-dimensional segmentation algorithm was used to calculate LVV and LVEF.
  
  
  RESULTS
  Mean LVEF measured with 13N-NH3 was 45.6±8.9 and 75.3±9.4%, mean ESV was 0.40±0.12 and 0.14±0.11 ml, and mean EDVwas 0.53±16 and 0.75±0.18 ml for MI and control rats, respectively. Moderate to good correlations were observed between values of 13N-NH3 and 18F-FDG for calculation of ESV [r=0.80, P<.0001, standard error of estimate (SEE)=0.10], EDV (r=0.63, P=.005, SEE=0.14) and LVEF (r=0.84, P<.0001, SEE=9.5). LVEF measured with 13N-NH3 was significantly lower in MI rats in comparison to measurement with 18F-FDG (45.6±8.9 vs 54.9±9.3 %; P=.04).
  
  
  CONCLUSIONS
  Correlations were moderate to good for the assessment of ESV, EDV and LVEF between gated 13N-NH3 and 18F-FDG. LVEF was underestimated with gated 13N-NH3 in rats with myocardial infarction. In healthy rats, LV volumes and LVEF can be measured reproducibly with either approach.
authors.affiliation: Department of Cardiology, University Medical Center Groningen, University of Groningen, P.O. Box 30001, 9700 RB Groningen, The Netherlands.
authors.forename: Mariusz K
authors.initials: MK
authors.lastname: Szymanski
authors.forename: Silvana
authors.initials: S
authors.lastname: Kruizinga
authors.forename: René A
authors.initials: RA
authors.lastname: Tio
authors.forename: Antoon T M
authors.initials: AT
authors.lastname: Willemsen
authors.forename: Michael A
authors.initials: MA
authors.lastname: Schäfers
authors.forename: Lars
authors.initials: L
authors.lastname: Stegger
authors.forename: Rudi A
authors.initials: RA
authors.lastname: Dierckx
authors.forename: Hans L
authors.initials: HL
authors.lastname: Hillege
authors.forename: Riemer H J A
authors.initials: RH
authors.lastname: Slart
mesh_terms: D000641:Ammonia; D000818:Animals; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D008297:Male; D009590:Nitrogen Radioisotopes; D049268:Positron-Emission Tomography / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D013318:Stroke Volume; D016277:Ventricular Function, Left
chemical_list: D009590:Nitrogen Radioisotopes; D000641:Ammonia