Allen Xu, BioE intern
5/25/2017 3:00:34 PM
Giang-Chau Ngo, a member of Professor Brad Sutton’s research group, has received a 2017 Dissertation Completion Fellowship from the University of Illinois Graduate College. Sutton’s lab in the Beckman Institute focuses on accurate image acquisition and reconstruction of magnetic resonance imaging of the brain to study the cognitive effects of aging and the neuromuscular dynamics of speech and swallowing.
The overarching goal of Ngo’s research is to use functional Magnetic Resonance Imaging (fMRI) to detect brain activity. fMRI is based on a property known as blood oxygenation level dependent (BOLD) contrast, and is used to map neural activity.
However, air/tissue interfaces around the brain, such as near the sinuses and ears, introduce magnetic field inhomogeneity (MFI), which causes distortions in the magnetic field and disrupts the accuracy of fMRI scans. Due to the location of these air/tissue interfaces, this is particularly disruptive in areas of the brain related to memory and emotional processing, regions which are frequently investigated for age-related memory problems and other mental health issues.
Ngo is trying to develop a framework that could account for these distortions and ultimately result in better imaging. “I am developing a tool that enables more robust imaging, and minimizes the bias that you can get when using standard methods,” says Ngo, “You need a very homogenous magnetic field to be able to get accurate measurements. If I can model the distortion of the magnetic field, I can use a model-based framework to recover accurate functional MRI information reflecting true brain activity.”
The strategy is to model the distortions caused by inhomogeneity and separate the functional brain signal into two components, a signal magnitude and a decay rate, T2*. Changes in T2* decay quantitatively indicate brain function, but magnetic field inhomogeneity prevents accurate measurements. In order to account for the distortions, a T2* estimation framework is required, but this is a challenging non-linear estimation problem.
Ngo’s research involves developing a method that accounts for the distortion introduced by MFI around air/tissue interfaces and estimating the image, the MFI distortion, and the brain-function-related decay signal. This work could have a significant impact on future fMRI studies, enabling accurate measures of brain function.
The campus Dissertation Completion Fellowship is awarded each year to a select group of exceptional graduate students who are expected to complete their dissertation by August of the following year. Winners receive waivers for school fees, partial payment for health insurance, as well as a $20,000 stipend. The generous fellowship enables students to focus on the completion of their dissertation full-time, without other obligations like teaching or part-time employment.
In addition to this fellowship, Ngo has received support for her research from several other campus fellowships, including the Beckman Graduate Fellowship and the Nadine Barrie Smith Memorial Fellowship.
After earning her PhD, Ngo plans to continue in the field of research, either at a university or research institution. “I would like to thank my lab mates and my advisor for their help,” Ngo said. “I’d also like to thank the Graduate College for giving me this fellowship.”