Magnetic susceptibility has long been known to cause spatial distortions and signal loss in functional neuroimaging experiments using the blood oxygenation level dependent (BOLD) response. These can cause mis-mapping of brain function or complete loss of signal in brain regions near air/tissue interfaces. However, an additional effect exists from the magnetic susceptibility differences that can induce spatial variations in the sensitivity of a BOLD fMRI experiment. The sensitivity changes can depend on subject-specific anatomy and on the acquisition sequence that is chosen for fMRI. In this presentation, I will describe how functional MRI signals are acquired and demonstrate the impacts of magnetic field inhomogeneity resulting from magnetic susceptibility variations around the brain.
Brad Sutton is an Associate Professor in the Bioengineering Department at the University of Illinois. He received a B.S. in General Engineering from the University of Illinois at Urbana-Champaign. He earned M.S.’s in Biomedical and Electrical Engineering and a PhD in Biomedical Engineering from the University of Michigan in 2003. He has affiliations with the Beckman Institute, Electrical and Computer Engineering Department, the Department of Speech and Hearing Sciences, and the Neuroscience Program. His research interests are in developing magnetic resonance imaging acquisition, image reconstruction, and systems modeling approaches to understand brain function, blood flow, motor control, and aging. He has over 60 peer reviewed journal publications, over 100 conference papers, and three patents in the area of image acquisition with MRI.