Hepatic Sugar Metabolism Measured by PET/CT in Patients and Healthy Subjects
Condition: Liver Cirrhosis
MeSH terms: Liver Cirrhosis
Study type: Observational

Summary: 
      The investigators wish to determine the lumped constant (LC), which is a correction factor
      necessary for converting measurements of hepatic FDG metabolism (measured by PET) to those of
      regular glucose in patients with cirrhosis and healthy subjects.

      Working hypothesis

        -  LC for FDG in liver tissue is not significantly different from unity in healthy subjects

        -  LC for FDG in liver disease is significantly different from LC in healthy liver

        -  Insulin changes the LC for FDG in liver tissue, but not by the same factor in liver
           disease and healthy subjects.
    

Detailed description: 
      The LC for FDG is determined in 8 patients with liver disease and 8 healthy volunteers with
      and without glucose-clamp on two different days at 3-5 week intervals. The individual order
      of the two examinations will be randomized. The subjects fast overnight before the
      examination but are allowed to drink water and take usual medication.

      When arriving at the PET centre, venflons are placed in a cubital vein in both arms and an
      ICG infusion is started in one of them. On the day with the glucose-clamp, an infusion of
      insulin and glucose is started in the second venflon. Next, an artflon is placed in one
      radial artery and a lever vein catheteter is placed via an introducer catheter in the left
      femoral vein under sterile conditions and local anesthetic (Lidocaine). The position of the
      liver vein catheter is checked with fluoroscopy.

      On each experimental day, a bolus of 200 MBq FDG + 25 μCi [3H] glucose (diluted with saline
      up to 10 ml) is given intravenously at the start of a 60-min PET scan of the liver. Blood
      samples from a peripheral artery and a liver vein are collected for determination of blood
      concentrations of FDG and [3H]glucose at appropriate intervals.

      In the experiment with glucose-clamp, an intravenous infusion of insulin (0.6 mU/kg/min) is
      given and blood glucose is measured every 10 min and kept constant at around 5 mM by infusing
      20% glucose (infusion rate adjusted according to blood glucose).

      During each study, the hepatic blood flow rate is measured by giving an intravenous infusion
      of indocyanine green (ICG) and collecting arterial and liver vein blood samples (Fick's
      principle).

      Blood samples are analyzed for concentrations of FDG (gammacounter), [3H]glucose
      (liquid-scintillation counter), glucose (enzymatic assay) and ICG (spectrophotometric).

      When the experiment is finished, all infusions are terminated and the liver vein catheter is
      removed and hemostasis ensured by manual compression (10 minutes) and bed rest for 30 minutes
      before the subject is allowed to stand. The artflon is then removed and hemostasis ensured by
      manual compression (10 minutes). Finally, the venflons are removed.
    

Intervention name(s): Liver vein catheter
Intervention type(s): Procedure
Intervention description(s): Liver vein catheter is placed in the heptic vein via the femoral vein, using fluoroscpoy as guidance.
Other intervention name(s): Cook, Torcon NB Advantage Catheter
Intervention MeSH terms: Imidacloprid
Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Recruited via 2 newspapers: Århus Onsdag and Århus Stiftstidende, and so will be based in
        the area these newspapers are distributed in.
      
Biospecimen description: 
      Plasma for measuring levels of ICG, insulin, c.peptide, FFA, glucagon,and 3H-glucose.
    
Keywords: Lumped constant; FDG; PET