@article {390, title = {Gas flow MRI using circulating laser-polarized Xe-129}, journal = {Journal of Magnetic Resonance}, volume = {138}, year = {1999}, note = {J Magn Reson196HXTimes Cited:35Cited References Count:15}, month = {May}, pages = {155-159}, abstract = {

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.

}, keywords = {xenon}, isbn = {1090-7807}, doi = {Doi 10.1006/Jmre.1998.1675}, url = {://WOS:000080303900021}, author = {Brunner, E. and Haake, M. and Kaiser, L. and Pines, A. and Reimer, J. A.} }