A dual-tuned resonator for proton-decoupled phosphorus-31 chemical shift imaging of the brain.

A fully quadrature dome-shaped resonator is presented that has been dual-tuned for proton and phosphorus operation at 1.5 T. The resonator is 16.5 cm in length and 23 cm in diameter. Phantom studies were performed to demonstrate the utility of the resonator for proton imaging, shimming, and proton-decoupled phosphorus spectroscopy. In human subjects, proton-decoupled phosphorus chemical shift imaging spectra of the brain were acquired at 27 cm3 resolution in 34 min. Volunteer studies demonstrated improved resolution of phosphomonoesters, phosphodiesters, and nucleoside triphosphates due to proton decoupling. Sensitive coverage of the brain extended from the most superior cerebral cortex to the cerebellum. Acquisition of good quality 31P spectra over this volume is due to the dome structure as well as quadrature operation at both proton and phosphorus frequencies.