Project Summary Detecting and characterizing lung disorders and their impacts on the airways by imaging is extremely challenging due to the low tissue density. Few options exist to characterize the changes in the microscopic properties of air access and tissue changes in diseases such as asthma, pneumonia, bronchitis, Covid-19, and chronic obstructive pulmonary disease. MRI with hyperpolarized gasses, such as 3He and 129Xe have been used to fill this gap, which however have their own limitations related to cost, complexity of implementation, compatibility of existing equipment, and some non-negligible biological effects of the gasses. This project will deliver an alternative approach, based on aerosolized hyperpolarized water vapor (AHWV), which will be fully biocompatible, portable, compatible with existing imaging hardware, and will allow probing lung volume at different length scales. The approach is based on Overhauser Dynamic Nuclear Polarization (ODNP) of water, followed by aerosolization of hyperpolarized water such that it can be imaged. For this exploratory program, we will develop an open-source, low field (0.2T) ODNP system to hyperpolarize water in the liquid phase that will be rapidly vaporized by an aerosolization reactor. Relaxation properties of water in vapor form will be studied at different magnetic field strengths, temperatures and aerosolization approaches to determine the optimal conditions for vapor polarization, delivery into the measurement volume and optimization of sensitivity. The method will be on a mouse animal model on a 3T animal scanner. Overall, we will establish an effective method to hyperpolarize and aerosolize water and will develop the necessary tools required to acquire hyperpolarized water-in-air images in void-spaces. The study is expected to lay the foundation for this new portable, cost-effective, and flexible imaging modality for the airways.