Chapter 20: ¹²⁹Xe Chemical Shift and Spin–Lattice Relaxation Dependences on Blood Oxygenation

In this chapter, the NMR behaviour of hyperpolarised ¹²⁹Xe in human blood is evaluated. Specifically, the changes in the spin–lattice relaxation and chemical shift of ¹²⁹Xe in vitro as a function blood oxygenation are presented and discussed. The magnetic properties of xenon in haemoglobin (Hb), and xenon–Hb binding, are used to try and explain the observed spin–lattice relaxation and chemical shift dependencies on blood oxygenation. Additionally, preliminary in vivo data of dissolved-phase ¹²⁹Xe in healthy human lungs is shown, where the blood oxygenation estimated over breath-hold by using the observed in vitro ¹²⁹Xe chemical shift blood oxygenation dependence for calibration.