On optimizing contrast quality and acquisition time of SSFP-squence-based techniques for structural and functional MR Imaging via extended phase graph (EPG) analysis

Structural and functional magnetic resonance imaging (MRI/fMRI) has been an excellent neuroimaging tool, relying on which neuroscientists have been able to define different brain functional regions and measure neural activities within those regions. As it stands now, the most commonly used functional MRI technique, Echo Planar Imaging (EPI), performs reasonably well, but this imaging technique faces a number of long-standing issues. Specifically, the EPI images suffer from two types of image artifacts, signal dropout and geometric distortion, especially when images are acquired from brain regions around the air/tissue interface. In addition to the known image artifacts, it is understood that the technique does not provide functional images with the optimal resolution to capture spatially distributed fine neural activation.;For structural imaging, many different techniques are available to allow delineation of detailed brain regions. A particular technique, Magnetization-Preparation RApid Gradient Echo (MP-RAGE), has received much attention for its potential of providing structural images with great tissue contrast and obtaining them with rapid imaging time. However, this technique has not been fully optimized in terms of image quality and acquisition time. Our main goal is to improve/optimize both structural and functional MRI in order to contribute to the study of neurophysiology.;In light of our motivation, we have designed an optimization framework for MP-RAGE to enable acquisition that satisfies specified image quality criteria of signal intensity and contrast ratio of/between different tissues in the shortest amount of time. It allows us to perform highly quantitative structural imaging and customized imaging for any individuals. We have also designed a novel functional MRI technique called Frequency-Modulated TRUe Fast Imaging with Steady-state Free Precession (FM TruFISP) and different post image processing techniques to take advantage of the FM TruFISP functional image acquisition. The combined use of the new acquisition and processing techniques allow us to address the issue of the EPI image artifacts and perform highly quantitative functional imaging. The MP-RAGE optimization framework and the FM TruFISP design are discussed in detail in the body of this dissertation, and the Appendix B includes the developed Matlab programs that perform magnetization (signal) calculation/simulation necessary for applying the framework and the different post image processing techniques.