%0 Journal Article %J Journal of Magnetic Resonance %D 1999 %T Gas flow MRI using circulating laser-polarized Xe-129 %A Brunner, E. %A Haake, M. %A Kaiser, L. %A Pines, A. %A Reimer, J. A. %K xenon %X

We describe an experimental approach that combines multidimensional NMR experiments with a steadily renewed source of laser-polarized Xe-129. Using a continuous flow system to circulate the gas mixture, gas phase NMR signals of laser-polarized Xe-129 can be observed with an enhancement of three to four orders of magnitude compared to the equilibrium Xe-129 NMR signal. Due to the fact that the gas flow recovers the nonequilibrium Xe-129 nuclear spin polarization in 0.2 to 4 s, signal accumulation on the time scale of seconds is feasible, allowing previously inaccessible phase cycling and signal manipulation. Several possible applications of MRI of laser-polarized Xe-129 under continuous flow conditions are presented here. The spin density images of capillary tubes demonstrate the feasibility of imaging under continuous how. Dynamic displacement profiles, measured by a pulsed gradient spin echo experiment, show entry flow properties of the gas passing through a constriction under laminar flow conditions. Further, dynamic displacement profiles of Xe-129, flowing through polyurethane foams with different densities and pore sizes, are presented. (C) 1999 Academic Press.

%B Journal of Magnetic Resonance %V 138 %P 155-159 %8 May %@ 1090-7807 %G English %U ://WOS:000080303900021 %N 1 %M WOS:000080303900021 %! Gas flow MRI using circulating laser-polarized Xe-129 %R Doi 10.1006/Jmre.1998.1675