Being able to identify regions of the lung that are well ventilated does not provide a full functional diagnostic. Only regions of the lung that are well ventilated and are extracting oxygen from the inspired gas are contributing to the life sustaining mission of the lung. MagniXene™ has the potential for evaluating lung regions based on their ability to extract oxygen. Once magnetized, xenon will slowly lose its magnetization in storage over a period of hours. Once breathed into the lungs, however, it loses its magnetism in tens of seconds. The predominant underlying process causing loss of magnetism is the presence of oxygen. Regions of the lung with good blood flow and normal oxygen uptake have lower oxygen concentrations than normal air, and lower than regions of the lung where oxygen is not being removed. Consequently the magnetism of MagniXene™ can be monitored by the MRI scanner, and the local oxygen partial pressure can be determined by how fast the magnetism in that region drops.