Medical applications of fluorine-19 and hyperpolarized xenon129 magnetic resonance imaging

Abstract

Multinuclear magnetic resonance imaging (MRI) is currently under extensive development. Although conventional proton MRI is mostly known as an anatomical medical imaging modality with an excellent soft tissue contrast, multinuclear MRI proves that MRI can provide researchers and clinicians with information about the internal organs function. This class of MRI techniques relies on imaging different nuclei than protons. A large part of multinuclear MRI includes fluorine-19 (19F) and hyperpolarized (HP) xenon-129 (129Xe) MRI. 19F MRI is used for functional imaging of the lungs, molecular imaging of fluorinated biosensors, cell labeling, and drug metabolism investigation. On the other hand, HP 129Xe can be used for functional brain imaging along with perfusion imaging of the brain and kidneys. This thesis is focused on the development of HP 129Xe Time-of-Flight (TOF) perfusion imaging technique, functional lung imaging using octafluorocyclobutane (OFCB), and colorectal adenocarcinoma resistivity detection to 5-fluorouracil (5-FU) using 19F MRI. HP 129Xe TOF pulse sequence is capable to map and measure perfusion quantitively was developed and evaluated in phantoms and healthy volunteers. As a representative application, HP 129Xe TOF perfusion imaging was used to detect hemodynamic response to motor and visual stimuli in healthy brains. The performance of OFCB as a contrast agent has been evaluated in vitro and in vivo and compared to perfluoropropane, which is the most commonly used inhalation agent for 19F lung MRI. Theoretical comparison between both gases was conducted as well. Finally, resistivity detection of human colorectal adenocarcinoma to 5-FU was performed using 19F chemical shift imaging to access chemotherapy retention in the colorectal cancer. This work expands the arsenal of multinuclear MRI techniques with completely new approaches that can be readily applied for the current needs of neurology, pulmonology, and oncology.