Professor of Radiology
The primary mission of the Functional and Metabolic Imaging Group (FMIG) is the development and application of novel hyperpolarized MRI techniques to the diagnosis of various pulmonary and metabolic disorders. Hyperpolarization, the process of drastically increasing the population difference between nuclear spin states, provides a platform for imaging lung physiology and metabolic activity with spatial and temporal resolution unattainable with conventional MRI techniques, thus offering the potential for the earlier diagnosis of disease states and the precise monitoring of a patient's response to medical treatment. This core research theme is executed with an eye toward several ultimate goals: the identification of changes in pulmonary structure and function associated with disease, a more complete understanding of pathogenesis, and the establishment of a more sensitive testing environment to develop treatments for lung disease. To date, significant contributions in these areas include new imagining techniques for the comprehensive description of lung physiology and structure, accurate imaging of the regional pulmonary partial pressure of oxygen in both humans and large and small animals, highly developed imaging of regional ventilation, and a state-of-the-art mechanical ventilation device. Specifically, our research activities at FMIG is divided into four general branches:
The development of novel imaging techniques for the quantitative assessment of pulmonary structure and function: Important pulmonary physiology parameters, such as ventilation, blood/air gas exchange, inflammation, and perfusion, can be monitored and quantified with high spatial and temporal resolution through the use of hyperpolarized gas (3He and 129Xe) MRI. (Perfusion may also be imaged with hyperpolarized 13C MRI.) These methods of measurement are employed in the study of common pulmonary disease models: most notably, COPD, emphysema, asthma, and cystic fibrosis. In parallel, FMIG is investigating the use of hyperpolarized 13C-bicarbonate for imaging regional pulmonary pH, an important indicator for a number of pathologies.
The development of novel methods for real-time metabolic imaging: Hyperpolarized 13C MRI has strong potential for the real-time imaging of metabolic activity in vitro and in vivo. Hyperpolarized 13C-labeled metabolites (e.g., [1-13C]pyruvate) can be delivered to a living subject or a cell culture and subsequently used to detect aberrant metabolism, which is a key pathological indication for a number of disease states, including cancer. This research objective includes the in vitro characterization of 13C imaging agents under physiological conditions and the more extreme conditions typical to hyperpolarization techniques.
The construction of novel polarization apparatuses: FMIG intends to build a novel 13C DNP research polarizer that improves upon commercial polarization apparatuses in two ways. Firstly, the new polarizer will be capable of the high-throughput needed to dramatically improve in vivo studies. Secondly, the polarizer will provide control of hyperpolarization parameters (most importantly, field strength), allowing the researchers to probe the limiting factors of polarization and develop new 13C tracers and measurement techniques for studying the respiratory system.
The development and implementation of rapid imaging pulse sequences: Because of the loss of signal (longitudinal relaxation) with time inherent to hyperpolarized MRI, FMIG builds pulse sequences specially suited to rapid imaging.