Investigational Pulmonary Ventilation and Perfusion Imaging Techniques in Swine

Pulmonary ventilation MRI, though not yet in clinical use, shows great potential for assessing regional pathology in pulmonary disease such as asthma. Hyperpolarized noble gas MRI is the emerging gold reference standard for pulmonary ventilation imaging, but this technique remains challenging due to the expense of the rare gas 3He. The isotope 129Xe is more widely available than 3He, existing at a natural abundance of ~26% in the atmosphere and so is a more viable clinical alternative to 3He MRI – the established reference standard. However, both polarized gas methods require customized gas polarizer hardware that is not widely available commercially. Oxygen enhanced (OE) MRI is an inexpensive alternative to hyperpolarized gas MRI that uses commercially available hardware without the need for expensive polarization equipment. However, the potential of this new technique has not yet been fully evaluated in comparison to established hyperpolarized gas methods in well controlled experiments. Purpose: We will test the hypothesis that ventilation and perfusion defects will correspond to regions of abnormal oxygen enhancement for the new OE-MRI method. This is especially relevant since it is not known whether the oxygen that is acting as a contrast-agent is most affected by ventilation or perfusion and this remains a critical question for verifying the role of this technique for detection of lung disease.