To my parents, Janet and David, to my sister, Julie, to my extended family, My heartfelt appreciation to my significant other, Jie Xu, for her love, support, andįriendship. Wes Baker, Kejia Cai, and Anup Singh for their assistance with experiments. Would also like to thank Eric Mellon, Santosh Gaddam, Victor Babu, Teruyuki Hiraki, Susan Colleluori for all her assistance with all matter administrative and otherwise. Including graduate students, post-docs, and staff for their support. I would also like to thank all the members of the Reddy lab, I am also indebted to otherįaculty members who have also provided me with substantial support, especially Johnĭetre and Joel Greenberg. Magland, and Mark Elliott for their guidance along the way. Members of my working thesis committee, Felix Wehrli, Ari Borthakur, Jeremy I want to express my sincere gratitude to my thesis advisor, Ravinder Reddy, and the Work represents several important steps towards making hyperoxia a more quantitative MRI contrast agent for Model to describe the relationship between CBF, oxygen consumption, and hyperoxic T1reduction isĭeveloped, which allows for a more rigorous physiological interpretation of these data. Model, with our results comparing favorably to17O2measurements of absolute metabolism. In Chapter 5, hyperoxic gasĬalibration of BOLD/ASL data is used to measure cerebral oxygen metabolism in a hypermetabolic swine Using simultaneous ASL and in vivoT1ameasurements, as described in Chapter 4. The effect of both the degree and duration of hyperoxic exposure on absolute CBF are quantified Since ASL measurements are highly sensitive toĪrterial blood T1(T1a), the value of T1a in vivois determined as a function of arterial oxygen partial pressure Mitigates this effect while maintaining BOLD contrast. Studies is characterized as a function of static field strength, and we show that optimum reduction in FiO2 In Chapter 2, the artifactual influence of paramagnetic molecular oxygen on BOLD-modulated hyperoxic gas Quantitative measurements of metabolism, and (4) biophysical mechanisms of hyperoxic T1contrast. Temporal characteristics of hyperoxia-induced reductions in cerebral blood flow (CBF), (3) use of oxygen in Paramagnetic effects of molecular oxygen BOLD and arterial spin labeling (ASL) data, (2) degree and Specifically, our work focuses on the following areas: (1) The hope of increasing its precision and utility. ![]() This thesis aims to obtain a more quantitative understanding of intravascular hyperoxic contrast in vivo, with Signal – of which there remain many crucial missing pieces. Quantitative measurements using this contrast agent depend on the precise knowledge of its effects on the MR Ischemic stroke penumbra, oxygen delivery to tumors, and functional MRI data calibration. Many research and clinical applications using hyperoxic contrast have recently emerged, including delineating Increased T2from deoxyhemoglobin dilution in venous compartments (blood oxygenation level-dependentĮffect or BOLD) and reduced T1from paramagnetic molecular oxygen dissolved in blood plasma and tissues. Increasing the fraction of inspired oxygen (FiO2) generates MR contrast by two distinct mechanisms:
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