Design, Construction, and Validation of Magnetic Particle Imaging Systems for Rodent, Primate, and Human Functional Neuroimaging

Abstract

Non-invasive neuroimaging techniques, such as functional magnetic resonance imaging, enabled a paradigm shift in the way neuroscientists study the brain. With these techniques, different levels of brain function can be safely localized in humans, allowing the study of diseases. However, due to the sensitivity limitations of the existing methods, it often requires averaging across large cohorts (up to 100s of subjects) to discern significant differences. Magnetic Particle Imaging (MPI) is a new imaging modality that may overcome this sensitivity limitation due to its very strong signal strength paired with a lack of biological background signals and noises. Previously, MPI instrumentation had not been developed at the human scale capable of functional neuroimaging. The goals of this thesis are to demonstrate the feasibility of MPI at this scale. First, the general principles of MPI design are discussed, then functional neuroimaging experiments on the rat brain are shown with up to 6x the sensitivity of 9.4T MRI, and finally the human-scale MPI system design and implementation is presented with an analysis of its measured sensitivity. MPI, with its unprecedented sensitivity, may catalyze a new class of neuroimaging experiments as well as open the door to using functional neuroimaging for diagnostics in a variety of diseases.