title: Comparison of PET with radioactive microspheres to assess pulmonary blood flow.
abstract: Microsphere technique is the reference for assessment of pulmonary blood flow (PBF) but is destructive; PET, however, can determine PBF noninvasively. Comparisons of these 2 methods are scanty. Our study aimed at comparing these 2 techniques using a mathematic model taking into account the right ventricle in determining the transit time of a tracer through lung tissue.
  
  
  METHODS
  Ten normal pigs were investigated at baseline, during dobutamine infusion, and during 10 cm H(2)O of positive end-expiratory pressure. Under each condition, PBF was successively measured with PET (PET-PBF) and radioactive microspheres (MS-PBF). For PET-PBF, 2 mCi (74 MBq) (15)O-labeled water were injected intravenously over 20 s and PET scanning was performed for 10 min. The input function was determined noninvasively from PET and invasively from mixed venous blood withdrawals. PET-PBF was computed using a mathematic model taking into account the right ventricle in determining the transit time of the tracer through lung tissue. For MS-PBF, 1 given isotope was injected under a given condition. PET-PBF and MS-PBF for 5 lung regions were compared.
  
  
  RESULTS
  PET-PBF significantly correlated with MS-PBF both over all experimental points (PET-PBF = 0.79. MS-PBF + 1,538; r = 0.79; P < 0.001) and in separate lung regions. Invasive and noninvasive input functions also correlated significantly (r = 0.90; P < 0.001). Simulations stressed the crucial role of the right ventricle to the transit time of tracer through lung tissue in the determination of PET-PBF.
  
  
  CONCLUSIONS
  PBF can accurately be assessed using PET and a mathematic model taking into account the right ventricle in determining the transit time of a tracer through lung tissue. Noninvasive determination of the input function of the right ventricle is accurate and can readily be used for clinical applications.
authors.affiliation: Equipe d'Accueil 1896, Université Claude Bernard Lyon I, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Richard
authors.forename: Marc
authors.initials: M
authors.lastname: Janier
authors.forename: Francois
authors.initials: F
authors.lastname: Decailliot
authors.forename: Didier
authors.initials: D
authors.lastname: Le Bars
authors.forename: Franck
authors.initials: F
authors.lastname: Lavenne
authors.forename: Veronique
authors.initials: V
authors.lastname: Berthier
authors.forename: Martine
authors.initials: M
authors.lastname: Lionnet
authors.forename: Luc
authors.initials: L
authors.lastname: Cinotti
authors.forename: Guy
authors.initials: G
authors.lastname: Annat
authors.forename: Claude
authors.initials: C
authors.lastname: Guérin
mesh_terms: D000818:Animals; D003198:Computer Simulation; D005260:Female; D008297:Male; D008863:Microspheres; D011652:Pulmonary Circulation; D011868:Radioisotopes; D013552:Swine; D014055:Tomography, Emission-Computed; D016278:Ventricular Function, Right
chemical_list: D011868:Radioisotopes