Estimating kinetic parameters from dynamic contrast-enhanced T(1)-weighted MRI of a diffusable tracer: standardized quantities and symbols.
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.
Tofts
P S
PS
Department of Clinical Neurology, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom. p.tofts@ion.ucl.ac.uk
Brix
G
G
Buckley
D L
DL
Evelhoch
J L
JL
Henderson
E
E
Knopp
M V
MV
Larsson
H B
HB
Lee
T Y
TY
Mayr
N A
NA
Parker
G J
GJ
Port
R E
RE
Taylor
J
J
Weisskoff
R M
RM
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
D003287:Contrast Media; D019786:Gadolinium DTPA