A simple method for quantitative measurement and analysis of hyperpolarized 129Xe uptake dynamics in mouse brain under controlled flow

Abstract

We established a simple method for measuring and quantifying uptake dynamics of hyperpolarized (HP) 129Xe in mouse brain, which includes application of a saturation recovery pulse sequence under controlled flow of HP 129Xe. The technique allows pursuit of the time-dependent change in 129Xe nuclear magnetic resonance signal in the uptake process without effect from radiofrequency destruction of the polarization and the dynamics in mouse lung. The uptake behavior is well described by a simple model that depends only on a decay rate constant comprising cerebral blood flow and the longitudinal relaxation rate of HP 129Xe in the brain tissue. The improved analysis enabled precise determination of the decay rate constant as 0.107±0.013 s-1 (±standard deviation, n=5), leading to estimation of longitudinal relaxation time, T1i, as 15.3±3.5 s.