BME PhD Preliminary Exam Announcement for Neal Patel (V. Rayz, advisor) Everyone is invited to attend the public presentation beginning at 4:00 PM EST. Title: Characterization of CSF flow using physics-guided enhancement of 4D flow MRI Date and Time: Monday, April 3 at 4:00 PM EST Location: MJIS 2001 and Zoom link: https://iu.zoom.us/j/86147472960 Committee: Vitaliy L. Rayz, Chair; Amy J. Schwichtenberg; Edward J. Delp; Michael Markel Abstract: Cerebrospinal fluid (CSF) plays a diverse role within the skull including cushioning the brain, regulating intracranial pressure, and clearing metabolic wastes via the glymphatic system. Disruptions in CSF flow have long been investigated for hydrocephalus-related diseases. Recently, changes in CSF flow have been implicated in neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. It remains difficult to obtain in vivo measurements of CSF flow which would enable further study of disease initiation, progression, and treatment. Three-directional phase-contrast MR imaging (4D flow MRI) has been used to measure CSF velocities within the cerebral ventricles. However, there remain challenges in balancing acquisition time, spatiotemporal resolution, and velocity-to-noise ratio. This is complicated by the low velocities and long relaxation times associated with CSF flow. To address these challenges, we have applied physics-guided neural networks (PGNN) to super-resolve and denoise synthetic 4D flow MRI of CSF flow within the 3rd and 4th ventricles using novel loss functions. These loss functions are specifically designed to ensure that high-resolution estimations of flow fields are physically consistent and temporarily coherent. We apply these PGNN to various test cases including synthetically generated 4D flow MRI in the cerebral ventricles and vasculature, in vitro 4D flow MRI acquired at two resolutions in 3D printed phantoms of the 3rd and 4th ventricles, and in vivo 4D flow MRI in a healthy subject. Lastly, we propose to use these methods to investigate the influence of vasculature changes to CSF flow in the ventricles and associated implications to conditions such as idiopathic normal pressure hydrocephalus.