fMRI Acquisitions in Regions with Field Inhomogeneity

University Of Hawaii At Manoa, Honolulu HI

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Abstract

DESCRIPTION (provided by applicant): The purpose of this ROl proposal is to develop novel methods for the mitigation of magnetic susceptibility artifacts in T2* functional MR imaging (fMRI). The project has been motivated by the necessity for fMRl acquisition techniques in brain areas of vital importance for psychiatric and neuroscientific investigations but are, however, currently inaccessible to fMRI due to severe image degradation due to local field inhomogeneity. The primary goal of the proposal is to develop a rapid fMRI data acquisition strategy that is robust to local field inhomogeneity in both the in-plane and through-plane directions. The proposed acquisitions will allow for the collection of 14-18 slices in 1-2 seconds with significantly reduced signal loss and distortion compared to standard 2D methods with identical image resolution. As part of the research plan, variable density reversed spiral acquisitions, continuous gradient compensation methods, and 3D slice-select tailored RF pulses will be developed and systematically compared and combined. The comparison will be based on the criteria of acquisition speed, signal magnitude and resolution recovery, and T2* functional contrast. This project will lead to valuable new methods capable of imaging brain regions with large magnetic susceptibility variations in an accurate manner free of artifacts. Success in developing the methods described in this application will overcome a major limitation of fMRI, making feasible a broad range of clinical applications not previously possible. Many common disorders, such as schizophrenia, obsessive-compulsive disorder, depression, anorexia, and ADHD, which appear to involve disturbances in orbitalfrontal, striatal, and thalamic regions. will benefit from these techniques.