Modeling of Look-Locker estimates of the magnetic resonance imaging estimate of longitudinal relaxation rate in tissue after contrast administration

摘要: This paper models the behavior of longitudinal relaxation rate protons tissue water R1 (R1 = 1/T1), measured in a Look-Locker experiment at 7 Tesla after administration paramagnetic contrast agent (CA). It solves Bloch-McConnell equations for magnetization three-site two-exchange (3S2X) model with boundary conditions appropriate to repeated sampling magnetization. The extent which equilibrium intercompartmental exchange kinetics affect monoexponential estimates CA dynamic enhanced is described. relation between and concentration was calculated restricted intravascular, or intravascular extracellular compartments, by varying parameters mimic experimental data acquired rat cerebral tumor. described nearly linear relationship CA, but demonstrated that apparent relaxivity depends upon type. practical consequence this finding extended Patlak plot linearizes ΔR1 leaky microvessels, accurately determines influx across these underestimates volume blood water. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.