Dynamic NMR spectroscopy of hyperpolarized ¹²⁹Xe in human brain analyzed by an uptake model

Hyperpolarized (129)Xe (HpXe) NMR not only holds promise for functional lung imaging, but for measurements of tissue perfusion as well. To investigate human brain perfusion, several time-series of (129)Xe MR spectra were recorded from one healthy volunteer after HpXe inhalation. The time-dependent amplitudes of the MR spectra were analyzed by using a compartment model for xenon uptake modified to account for the loss of (129)Xe polarization due to RF-excitation and for the breathhold technique used in the experiments. This analysis suggests that the resonances detected at 196.5 +/- 1 ppm and 193 +/- 1 ppm originate from HpXe dissolved in gray and white matter, respectively, and that T(1) relaxation times of HpXe are different in gray and white matter (T(1g) > T(1w)).