Quantification of liver perfusion with [(15)O]H(2)O-PET and its relationship with glucose metabolism and substrate levels.
OBJECTIVE
Hepatic perfusion plays an important role in liver physiology and disease. This study was undertaken to (a) validate the use of Positron Emission Tomography (PET) and oxygen-15-labeled water ([(15)O]H(2)O) to quantify hepatic and portal perfusion, and (b) examine relationships between portal perfusion and liver glucose and lipid metabolism.


METHODS
Liver [(15)O]H(2)O-PET images were obtained in 14 pigs during fasting or hyperinsulinemia. Carotid arterial and portal venous blood were sampled for [(15)O]H(2)O activity; Doppler ultrasonography was used invasively as the reference method. A single arterial input compartment model was developed to estimate portal tracer kinetics and liver perfusion. Endogenous glucose production (EGP) and insulin-mediated whole body glucose uptake (wbGU) were determined by standard methods.


RESULTS
Hepatic arterial and portal venous perfusions were 0.15+/-0.07 and 1.11+/-0.34 ml/min/ml of tissue, respectively. The agreement between ultrasonography and [(15)O]H(2)O-PET was good for total and portal liver perfusion, and poor for arterial perfusion. Portal perfusion was correlated with EGP (r=or+0.62, p=0.03), triglyceride (r=or+0.66, p=0.01), free fatty acid levels (r=or+0.76, p=0.003), and plasma lactate levels (r=or-0.81, p=0.0009).


CONCLUSIONS
Estimates of liver perfusion by [(15)O]H(2)O-PET compared well with those by ultrasonography. The method allowed to predict portal tracer concentrations which is essential in human studies. Portal perfusion may affect liver nutrient handling.
Slimani
Lotfi
L
Turku PET Centre, Turku University Hospital, University of Turku, P.O. Box 52, FIN-20521 Turku, Finland. lotfi_slimani@hotmail.com
Kudomi
Nobuyuki
N
Oikonen
Vesa
V
Jarvisalo
M
M
Kiss
Jan
J
Naum
Alexandru
A
Borra
Ronald
R
Viljanen
Antti
A
Sipila
Hannu
H
Ferrannini
Ele
E
Savunen
Timo
T
Nuutila
Pirjo
P
Iozzo
Patricia
P
D000818:Animals; D005215:Fasting / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D006946:Hyperinsulinism / Q000378:metabolism; D007773:Lactates / Q000378:metabolism; D050356:Lipid Metabolism / Q000502:physiology; D008099:Liver / Q000000981:diagnostic imaging / Q000378:metabolism*; D008954:Models, Biological; D010104:Oxygen Radioisotopes; D010477:Perfusion / Q000379:methods*; D049268:Positron-Emission Tomography; D013552:Swine; D014280:Triglycerides / Q000378:metabolism; D018608:Ultrasonography, Doppler
D005230:Fatty Acids, Nonesterified; D007773:Lactates; D010104:Oxygen Radioisotopes; D014280:Triglycerides; D005947:Glucose