Chapter 22: Magnetic Resonance Imaging of the Brain using Hyperpolarized ¹²⁹Xe

The use of laser-polarized xenon-129 (¹²⁹Xe) as a novel contrast agent for magnetic resonance imaging (MRI) is quite useful for imaging the lungs and other organs such as the brain. From the earliest days of HP ¹²⁹Xe MRI, the original interest of one of the co-inventors (Dr Mitchell Albert) was to use ¹²⁹Xe to better understand the brain and directly image the effect of anaesthesia on brain function. Since xenon is a known anaesthetic and ¹²⁹Xe is a spin 1/2 nucleus it was a logical choice to study the effects of anaesthesia on the brain using MRI. In this chapter, we will briefly review some historical advancements for functional brain imaging, such as functional magnetic resonance imaging (fMRI) and the use of ¹²⁹Xe for animal and human brain imaging. The practical considerations for imaging the human brain using magnetic resonance will also be discussed. Considerations include: hyperpolarized gases, physical and chemical properties of xenon, routes and methods of delivery, physiological effects and patient safety. Finally, some basic ground-work and recent literature in the development of brain imaging using HP ¹²⁹Xe in animals and humans will be discussed.