Comparison of PET with radioactive microspheres to assess pulmonary blood flow.
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.
Richard
Jean-Christophe
JC
Equipe d'Accueil 1896, Université Claude Bernard Lyon I, France.
Janier
Marc
M
Decailliot
Francois
F
Le Bars
Didier
D
Lavenne
Franck
F
Berthier
Veronique
V
Lionnet
Martine
M
Cinotti
Luc
L
Annat
Guy
G
Guérin
Claude
C
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
D011868:Radioisotopes