Distinguishing Dose-Dependent Radiation Lung Injury using a Hyperpolarized 129Xe MRI Chemical Shift Saturation Recovery Technique

Motivation: Current methods for assessing radiation induced lung injury (RILI) lack detailed functional information. Goal(s): Our goal was to determine the sensitivity of chemical shift saturation recovery measurements in assessing and distinguishing dose-dependent RILI. Approach: We acquired measures of gas exchange and uptake in healthy and irradiated animals for right and left lungs separately. Results: Hyperpolarized xenon (HXe) dissolved in the pulmonary membrane showed an increase that scaled with radiation dose; HXe dissolved in red blood cells showed a decrease that scaled with radiation dose. Trends in HXe metrics correlate well with histology inflammation scores, enabling distinction of dose-dependent levels of radiation lung injury. Impact: We demonstrated a spectroscopic technique that shows sensitivity to differing degrees of radiation lung injury. This study lays the groundwork for future studies aimed at improving disease staging criteria in radiation lung injury, novel therapeutic development, and disease progression monitoring.