Optimization of the irradiation power in chemical exchange dependent saturation transfer experiments.

TitleOptimization of the irradiation power in chemical exchange dependent saturation transfer experiments.
Publication TypeJournal Article
Year of Publication2005
AuthorsSun PZ, van Zijl PCM, Zhou J
JournalJournal of magnetic resonance (San Diego, Calif. : 1997)
Volume175
Issue2
Pagination193-200
Date Published2005 Aug
Abstract

In chemical exchange dependent saturation transfer imaging experiments, exchangeable solute protons are saturated and the transfer of saturation to water is subsequently detected. When the applied irradiation power is comparable to the resonance frequency difference between the water protons and saturated solute protons, the proton transfer (PT) efficiency is reduced due to concomitant direct saturation effects. In this study, the PT process is modeled using a two-pool system. An empirical general proton transfer ratio (PTR) equation for arbitrary RF irradiation power is derived, and its optimal power to maximize the PTR is analyzed. The results are confirmed experimentally on 4.7 T using a poly-L-lysine solution. The theory provides a useful tool for optimizing the irradiation power of the PT sequences in the presence of direct saturation effects.

Alternate JournalJ. Magn. Reson.