Low-Cost, High-Throughput 3D Pulmonary Imaging Using Hyperpolarized Propane Gas
Abstract
There is currently no widespread clinical imaging modality to perform high-resolution functional lung imaging. Computed tomography (CT), conventional magnetic resonance imaging (MRI), and X-ray can only provide structural images of dense tissues—informing about pathologies like tumors and pneumonia—but yielding little or no information about lung ventilation, perfusion, alveoli size, gas-exchange efficiency, etc. Deadly diseases such as chronic obstructive pulmonary disease (COPD), asthma, acute lung injury, constrictive bronchiolitis, lung injury, and pulmonary fibrosis affect >300 million people worldwide and cause ~3 million annual deaths. These diseases do not have any clinical imaging marker as of today. This state of affairs contrasts with cancer imaging, which includes MRI, CT, ultrasound, mammography, positron emission tomography (PET) and others, which collectively enable early detection via population screening, diagnoses, and monitoring response to treatment. Furthermore, CT scans (2D and 3D X-ray) expose the body to ionizing radiation, and thus cannot be performed frequently due to increased risk associated with cancer-inducing radiation. On the other hand, MRI—particularly low-field MRI (proposed here)—involves no ionizing radiation, and is effectively non-invasive. Through our previous and ongoing Department of Defense funding support, we have developed and researched a suite of inexpensive technologies to enable high-throughput and low-cost functional 3D MRI of lungs, which can report on lung ventilation (i.e., how well air is reaching different parts of the lungs during respiration), and on lung gas diffusion (reporting on lung alveoli size, i.e., clusters of air sacks in the lungs responsible for transferring oxygen to the blood). Specifically, we have developed and studied clinical-scale production of hyperpolarized propane gas, which can be imaged using a conventional non-cryogenic low-cost low-field (LF) MRI scanner of 0.35 T or less, i.e., less than one-eighth of the magnetic field strength of a 3T MRI scanner. Hyperpolarized propane is generated through a process called Parahydrogen Induced Polarization (PHIP). Once propane is hyperpolarized, it can be used in MRI to provide 4-5 orders-of-magnitude signal enhancement, yielding 3D images with high spatial (down to sub-second scan speed) and temporal resolution and high contrast. Moreover, our recent pioneering work demonstrated a suitably long lifetime of hyperpolarized propane. LF-MRI in combination with hyperpolarized contrast agents provides distinct advantages over conventional high-field MRI—in that it can achieve and sometimes even exceed the detection sensitivity of conventional MRI scanners. LF-MRI scanners are significantly cheaper to build, house, and operate, and patients can be scanned standing in the physiological upright position— enabling “true” lung functionality studies that reflect gravitational effects that cannot be observed in a supine position. Furthermore, LF-MRI offers safer scans than conventional MRIs due to reduced heat deposition, can have virtually no exam hardware preparations (no magnet shimming), and has virtually no maintenance costs (e.g., expensive cryogens)—unlike conventional high-field MRIs. Moreover, LF-MRI enables approximately three times longer lifetime for the hyperpolarized propane gas contrast agent. If successful, this suite of technologies (propane hyperpolarizer and LF-MRI scanner) has great potential to revolutionize lung health care with low-cost and high-throughput imaging exams similar to X-ray, but instead providing functional 3D information. Food and Drug Administration (FDA)-approved LF-MRI scanners (including 0.35 T MRI scanner proposed here) are already commercially available, and propane gas (also known as E944) is already FDA-approved for unlimited use in foods applications. We hope to commercialize the production of propane hyperpolarizers to make them commercially availabl
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 10, 2021
- Source ID
- W81XWH2010576
Entities
People
- Eduard Y. Chekmenev
Organizations
- United States Army
- Wayne State University