Combining chemical exchange saturation transfer and H magnetic resonance spectroscopy for simultaneous determination of metabolite concentrations and effects of magnetization exchange.

Purpose: A new sequence combining chemical-exchange saturation-transfer (CEST) with traditional MRS is used to simultaneously determine metabolite content and effects of magnetization exchange.

Methods: A CEST saturation block consisting of a train of RF-pulses is placed before a metabolite-cycled semi-LASER single-voxel spectroscopy sequence. The saturation parameters are adjustable to allow optimization of the saturation for a specific target.

In vivo characterization of the downfield part of H MR spectra of human brain at 9.4 T: Magnetization exchange with water and relation to conventionally determined metabolite content.

Purpose: To perform exchange-rate measurements on the in vivo human brain downfield spectrum (5-10 ppm) at 9.4 T and to compare the variation in concentrations of the downfield resonances and of known upfield metabolites to determine potential peak labels.

Methods: Non-water-suppressed metabolite cycling was used in combination with an inversion transfer technique in two brain locations in healthy volunteers to measure the exchange rates and T values of exchanging peaks.

Elucidation of the downfield spectrum of human brain at 7 T using multiple inversion recovery delays and echo times.

Purpose: To characterize the downfield spectrum at 5-10 ppm in the human brain at a high magnetic field of 7 T. Knowledge of relaxation parameters is of interest for spectroscopy as well as chemical exchange-dependent saturation transfer experiments.

Methods: Water-suppressed spectra were recorded as echo time and inversion time series in healthy volunteers to investigate T and T values of downfield peaks in gray matter at 7T.