Figure 9.

Comparison of oxygen-concentration imaging using ¹²⁹Xe and ³He. Coronal maps of the partial pressure of oxygen (pO₂) were obtained in healthy subjects using either ¹²⁹Xe (left) or ³He (right). For both gases, the pO₂ values are generally uniform and in a range consistent with normal lung physiology, except for artifactually high values at the base of the lung caused by slight motion of the diaphragm during the acquisitions. Both images were obtained using a gradient-echo-based, cardiac-triggered, short-breath-hold implementation of pO₂ mapping (101). (¹²⁹Xe pO₂ map is from healthy subject #1 in ref. (101).)