Magnetic Resonance Imaging: Myelin Water Imaging and Model-Based Image Reconstruction

Passcode: magres

MRI is a useful imaging modality governed by complicated physics. One application of MRI is myelin water imaging (MWI). The traditional method for MWI is prohibitively slow and has not been widely adopted clinically. This dissertation introduces a faster MWI method that uses the STFR MRI scan. In addition, this dissertation develops a new method for optimizing scan parameters for improved MWI by minimizing the estimation error of the estimator to be used. Physical effects that are ignored by conventional MWI methods are modeled.

This dissertation also seeks to improve the quality of MRI images by modeling MRI physics during image reconstruction. MRI images can have regions with artificially low image intensity if the large magnetic field needed for MRI varies too quickly across space because signals at different spatial locations will be out of phase with each other. Therefore, this dissertation introduces a method where data is acquired with prephasing so the signals at different spatial locations start out of phase but then rephase as the signal is acquired. Then an image is reconstructed using a novel model-based reconstruction technique that models both the spatial variation of the magnetic field and the proposed prephasing acquisition scheme.

Chairs: Professors Jeffrey A. Fessler and Jon-Fredrik Nielsen