fcmrglu 0.3 © 2003,2004 by Turku PET Centre

Fits the three-compartment model to regional [18F]FDG brain PET data and estimates cerebral metabolic rate of glucose, CMRGlu (1). ______ ___________________ | | K1* | k3* | | | -----> | -------> | | Ca* | <----- | Ce* <------- Cm* | | | k2* | k4* | |______| |___________________| Ca K1* k3* CMRGlu = -------------- LC (k2* + k3*) Ca Steady-state glucose concentration in arterial plasma (mM) Ca* FDG concentration in arterial plasma (kBq/ml) Ce* FDG concentration in tissue (kBq/ml) Cm* FDG-6-phosphate concentration in tissue (kBq/ml) Vo* Apparent vascular volume of distribution of FDG in tissue Ct* Total radioactivity concentration in tissue; Ct* = Ce* + Cm* + Vo*Ca K1* Unidirectional clearance of FDG (ml/(ml min) k2* Relative clearance of FDG from tissue (1/min) k3* Rate constant of phosphorylation of FDG in tissue (1/min) k4* Rate constant of dephosphorylation of FDG in tissue (1/min) Ki* Steady-state clearance of FDG (ml/(ml min)); 'influx constant' LC Lumped constant (ratio) CMRGlu Cerebral metabolic rate of glucose (umol/(min 100 g)) The model is transformed to general linear least squares functions (2,3), which are solved using Lawson-Hanson non-negative least squares (NNLS) algorithm (4). A common LC for all reagions can be specified with option -LC. Otherwise LC will be calculated based on fixed transport and phosphorylation ratios between FDG and glucose, tau and phi, and regional parameters: LC = phi + (tau-phi) Ki*/K1* (5). Parameters: 1) Plasma file (preferably corrected for time delay, e.g. using fitdelay) 2) Tissue TAC file (*.dft) 3) Plasma glucose concentration (mM) 4) Fit end time (duration, in min) 5) Result file (existing file is overwritten) [6) Fitted tissue TAC file (optional) ] Options: -LC=<value> Use a fixed LC for all regions, e.g. 0.81 (6). -tau=<value> Set the transport ratio between FDG and glucose. Default tau=1.67 (7). -phi=<value> Set the phosphorylation ratio between FDG and glucose. Default phi=0.55 (7). -d=<value> Set the tissue density. Default is 1.04 g/ml. e.g.: fcmrglu -LC=0.81 ua5678ap.delay.kbq ua5678.dft 90 ua5678gur.res References: 1. Phelps ME, Huang S-C, Hoffman EJ, Selin C, Sokoloff L, Kuhl DE. Tomographic measurement of local cerebral glucose metabolic rate in humans with (F-18)2-fluoro-2-deoxy-D-glucose: validation of method. Ann Neurol 1979;6:371-388. 2. Blomqvist G. On the construction of functional maps in positron emission tomography. J Cereb Blood Flow Metab 1984;4:629-632. 3. Evans AC. A double integral form of the three compartmental, four rate- constant model fro faster generation of parametric maps. J Cereb Blood Flow Metab 1987;7(Suppl 1):S453. 4. Lawson CL & Hanson RJ. Solving least squares problems. Prentice-Hall, 1974. 5. Kuwabara H, Gjedde A. Measurements of glucose phosphorylation with FDG and PET are not reduced by dephosphorylation of FDG-6-phosphate. J Nucl Med 1991;32:692-698. 6. Wu H-M, Bergsneider M, Glenn TC, Yeh E, Hovda DA, Phelps ME, Huang S-C. Measurement of the global lumped constant for 2-deoxy-2-[18F]fluoro- D-glucose in normal human brain using [15O]water and 2-deoxy- 2-[18F]fluoro-D-glucose positron emission tomography imaging: a method with validation based on multiple methodologies. Mol Imaging Biol 2003; 5:32-41. 7. Crane PD, Pardridge WM, Braun LD, Oldendorf WH. Kinetics of Transport and Phosphorylation of 2-Fluoro-2-Deoxy-D-Glucose in Rat Brain. J Neurochem 1983;40:160-167.