Development of a Portable Animal Ventilator for Hyperpolarized 129Xe MRI and MRE at 9.4 Tesla

As a non-invasive and powerful method for assessing lung function, hyperpolarized (HP) 129Xe magnetic resonance (MR) imaging is increasingly being utilized in clinical settings to investigate various respiratory conditions. Concurrently, MR elastography (MRE) research holds promise in delivering crucial information regarding lung mechanical properties, particularly density and stiffness. Given the evolving nature of this field, numerous preclinical studies are still required. However, preclinical animal studies involving MRI and MRE encounter challenges such as the necessity for anesthesia, the need for precise delivery of very small tidal volumes (which affects gas administration accuracy), motion artifacts stemming from irregular breathing patterns during spontaneous respiration, and the demand for a high spatial resolution to detect regional changes. To surmount these limitations, this project proposes a portable HP gas ventilator that enables high-resolution 3D imaging of dissolved and gas-phase 129Xe in the lungs, compatible with a 9.4 Tesla MR system. The ventilator incorporates differential pressure transducers and a 3D-printed pneumotachometer, allowing for precise control of tidal volume, breathing cycles, and calibrated positive expiratory pressure in intubated animals. By leveraging low-cost microcontrollers, 3D-printed components, and open-source software, in addition to recapturing expelled HP gases, the overall cost per study is significantly reduced. The device is adaptable for use with various small animals, including rats, mice, guinea pigs, and rabbits, obviating the need for tracheotomy and substantially improving post-study survivability. Anesthesia is integrated into the oxygen supply, enabling prolonged testing durations while minimizing invasiveness. Future advancements will encompass the integration of the forced oscillation technique (FOT), thereby examining whether the combined utilization of MRI, MRE, and FOT can provide enhanced insights into complex lung function