The goal of this project is to apply a novel MRI-based imaging method to functional brain mapping, with the aim of achieving superior image quality, improved spatial resolution, and potentially improved activation signal. Conventional functional MRI (fMRI) imaging methods employ T2-weighted gradient-recalled echo (GRE) sequences, and suffer from image blur, distortion, and low activation contrast-to-noise ratio (CNR). Balanced steady-state free precession (bSSFP) fMRI has the potential to address these shortcomings, but introduces other sources of artifact and signal loss and has remained at the developmental stage. Using novel bSSFP pulse sequence design and parallel RF transmission, we have shown that robust, artifact-free bSSFP imaging is possible, provided that the B0 inhomogeneity across the imaging field-of-view (FOV) is sufficiently smooth. To assess the applicability of our method to functional imaging in the brain, we will measure whole-brain B0 patterns in volunteers, and use the observed values to optimize the pulse sequence design. The proposed method will be applied to passband bSSFP fMRI studies, and will be compared with conventional GRE BOLD fMRI. If successful, this project will produce an image acquisition sequence that is as flexible and robust as conventional GRE fMRI, but with reduced distortion and blur, potentially more accurate and reliable activation maps, and potentially superior contrast properties.
In this project, we will develop new and improved imaging technology for functional brain mapping experiments. Com- pared with current functional MRI methods, the new method will produce images of the brain with much finer detail.
