title: Quantification of liver perfusion with [(15)O]H(2)O-PET and its relationship with glucose metabolism and substrate levels.
abstract: 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.
authors.affiliation: Turku PET Centre, Turku University Hospital, University of Turku, P.O. Box 52, FIN-20521 Turku, Finland. lotfi_slimani@hotmail.com
authors.forename: Lotfi
authors.initials: L
authors.lastname: Slimani
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kudomi
authors.forename: Vesa
authors.initials: V
authors.lastname: Oikonen
authors.forename: M
authors.initials: M
authors.lastname: Jarvisalo
authors.forename: Jan
authors.initials: J
authors.lastname: Kiss
authors.forename: Alexandru
authors.initials: A
authors.lastname: Naum
authors.forename: Ronald
authors.initials: R
authors.lastname: Borra
authors.forename: Antti
authors.initials: A
authors.lastname: Viljanen
authors.forename: Hannu
authors.initials: H
authors.lastname: Sipila
authors.forename: Ele
authors.initials: E
authors.lastname: Ferrannini
authors.forename: Timo
authors.initials: T
authors.lastname: Savunen
authors.forename: Pirjo
authors.initials: P
authors.lastname: Nuutila
authors.forename: Patricia
authors.initials: P
authors.lastname: Iozzo
mesh_terms: 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
chemical_list: D005230:Fatty Acids, Nonesterified; D007773:Lactates; D010104:Oxygen Radioisotopes; D014280:Triglycerides; D005947:Glucose