Brain MRI with laser‐polarized 129xe

Abstract

The feasibility of brain MRI with laser‐polarized ¹²⁹Xe in a small animal model is demonstrated. Naturally abundant ¹²⁹Xe is polarized and introduced into the lungs of Sprague‐Dawley rats. Polarized xenon gas dissolves in the blood and is transported to the brain where it accumulates in brain tissue. Spectroscopic studies reveal a single, dominant, tissue‐phase NMR resonance in the head at 194.5 ppm relative to the gas phase resonance. Images of ¹²⁹Xe in the rat head were obtained with 98‐μl voxels by 2D chemical shift imaging and show that xenon is localized to the brain. This work establishes that nuclear polarization produced in the gas phases survives transport to the brain where it may be imaged. Increases in polarization and delivered volume of ¹²⁹Xe will allow clinical measurements of regional cerebral blood flow.