Determinants of tissue delivery for 129Xe magnetic resonance in humans

Abstract

Magnetic resonance imaging using laser-polarized ¹²⁹Xe is a new technique first demonstrated by Albert et al. (Nature 370, 1994) who obtained a ¹²⁹Xe image of an excised mouse lung. This paper describes the factors influencing the accumulation of inhaled, polarized ¹²⁹Xe in human tissue. The resulting model predicts the ¹²⁹Xe magnetization in different tissues as a function of the time from the start of inhalation, the tissue perfusion rate and partition coefficient for xenon, and the relevant T₁ decay times. The relaxation times of ¹²⁹Xe in biological tissues are not yet known precisely. Substitution of estimated values for these parameters results in an expected signal-to-noise ratio (SNR) from polarized ¹²⁹Xe MR in the brain of approximately 2% of the equivalent SNR from proton MR.