Imaging Human Brain Perfusion with Inhaled Hyperpolarized ¹²⁹Xe MR Imaging.

Abstract

Purpose To evaluate the feasibility of directly imaging perfusion of human brain tissue by using magnetic resonance (MR) imaging with inhaled hyperpolarized xenon 129 (¹²⁹Xe). Materials and Methods In vivo imaging with ¹²⁹Xe was performed in three healthy participants. The combination of a high-yield spin-exchange optical pumping ¹²⁹Xe polarizer, custom-built radiofrequency coils, and an optimized gradient-echo MR imaging protocol was used to achieve signal sensitivity sufficient to directly image hyperpolarized ¹²⁹Xe dissolved in the human brain. Conventional T1-weighted proton (hydrogen 1 [¹H]) images and perfusion images by using arterial spin labeling were obtained for comparison. Results Images of ¹²⁹Xe uptake were obtained with a signal-to-noise ratio of 31 ± 9 and demonstrated structural similarities to the gray matter distribution on conventional T1-weighted ¹H images and to perfusion images from arterial spin labeling. Conclusion Hyperpolarized ¹²⁹Xe MR imaging is an injection-free means of imaging the perfusion of cerebral tissue. The proposed method images the uptake of inhaled xenon gas to the extravascular brain tissue compartment across the intact blood-brain barrier. This level of sensitivity is not readily available with contemporary MR imaging methods. ^©RSNA, 2017.