Hyperpolarized 129Xe MRI of the Irradiated Lung using a Chemical Shift Imaging – Chemical Shift Saturation Recovery (CSI-CSSR) Technique

Motivation: Chemical shift saturation recovery (CSSR) measurements are incredibly useful for quantifying pulmonary gas exchange and uptake; because CSSR is a spectroscopic technique, however, such measures are only global in nature. Goal(s): Our goal was to develop an imaging-based technique for spatially-resolving CSSR measurements. Approach: We demonstrated our technique’s utility in a rodent model of radiation-induced lung injury. Results: Images of hyperpolarized-129Xe dissolved in the pulmonary membrane (Mem) and red blood cells (RBC) showed higher Mem signal and reduced RBC signal in radiated vs non-radiated lungs. Septal wall thickness (SWT) measurements derived on a quadrant level also revealed elevated SWT in the irradiated region. Impact: We demonstrated a new imaging technique for regionally quantifying radiation-induced alterations in pulmonary gas exchange and uptake. This study lays the groundwork for future investigations aimed at improving radiotherapy strategies, mitigating radiotoxicity, and treating radiation-associated illness.