Nonlinear PO2 Decay in Human Lungs During Long-Breath-Hold 3He MRI

Juan Parra-Robles¹, Martin Deppe¹, Salma Ajraoui¹, Kevin Teh¹, Steven R. Parnell¹, Jim M. Wild¹

In this work, the global lung pO₂ decay is measured using hyperpolarized ³He MR during prolonged breath-holds in human volunteers (up to 90 s) and analyzed with both the linear and exponential models. The effect of increased initial pO₂ was also studied. The results showed that for long breath-holds it is possible to observe the non-linearity of the pO₂ decay. These measurements substantiate previous observations over shorter breath-holds in animal models. The data may be used to obtain useful information about the physiology of oxygen uptake in the lungs during apnea and provide a more realistic physical basis for imaging based models of pO₂.