title: Estimating kinetic parameters from dynamic contrast-enhanced T(1)-weighted MRI of a diffusable tracer: standardized quantities and symbols.
abstract: We describe a standard set of quantity names and symbols related to the estimation of kinetic parameters from dynamic contrast-enhanced T(1)-weighted magnetic resonance imaging data, using diffusable agents such as gadopentetate dimeglumine (Gd-DTPA). These include a) the volume transfer constant K(trans) (min(-1)); b) the volume of extravascular extracellular space (EES) per unit volume of tissue v(e) (0 < v(e) < 1); and c) the flux rate constant between EES and plasma k(ep) (min(-1)). The rate constant is the ratio of the transfer constant to the EES (k(ep) = K(trans)/v(e)). Under flow-limited conditions K(trans) equals the blood plasma flow per unit volume of tissue; under permeability-limited conditions K(trans) equals the permeability surface area product per unit volume of tissue. We relate these quantities to previously published work from our groups; our future publications will refer to these standardized terms, and we propose that these be adopted as international standards.
authors.affiliation: Department of Clinical Neurology, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom. p.tofts@ion.ucl.ac.uk
authors.forename: P S
authors.initials: PS
authors.lastname: Tofts
authors.forename: G
authors.initials: G
authors.lastname: Brix
authors.forename: D L
authors.initials: DL
authors.lastname: Buckley
authors.forename: J L
authors.initials: JL
authors.lastname: Evelhoch
authors.forename: E
authors.initials: E
authors.lastname: Henderson
authors.forename: M V
authors.initials: MV
authors.lastname: Knopp
authors.forename: H B
authors.initials: HB
authors.lastname: Larsson
authors.forename: T Y
authors.initials: TY
authors.lastname: Lee
authors.forename: N A
authors.initials: NA
authors.lastname: Mayr
authors.forename: G J
authors.initials: GJ
authors.lastname: Parker
authors.forename: R E
authors.initials: RE
authors.lastname: Port
authors.forename: J
authors.initials: J
authors.lastname: Taylor
authors.forename: R M
authors.initials: RM
authors.lastname: Weisskoff
mesh_terms: D003287:Contrast Media / Q000493:pharmacokinetics*; D004058:Diffusion; D005110:Extracellular Space / Q000378:metabolism; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008954:Models, Biological; D009626:Terminology as Topic
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA