Hyperpolarized gas and oxygen-enhanced magnetic resonance imaging.

Unlike any other organ, imaging of lungs with magnetic resonance faces unique challenges owing to the complex microstructure and presence of gas-tissue interfaces. With the evolution of faster and stronger gradient systems leading to ultrafast imaging with ultrashort echo times, pulmonary magnetic resonance imaging (MRI) is no longer considered a technical challenge. In terms of functional evaluation, lungs are also associated with a unique function, viz. ventilation. Evaluation of ventilation is feasible with MRI either by using hyperpolarized noble gases or in an indirect fashion by performing oxygen-enhanced MRI. This chapter will provide an overview of these two methods.