Sparsity in MRI RF excitation pulse design

—Magnetic resonance imaging (MRI) may be viewed as a two-stage experiment that yields a non-invasive spatial mapping of hydrogen nuclei in living subjects. Nuclear spins within a subject are first excited using a radio-frequency (RF) excitation pulse and proportions of excited spins are then detected using a resonant coil; images are then reconstructed from this data. Excitation pulses need to be tailored to a user’s specific needs and in most applications need to be as short as possible, due to spin relaxation, tissue heating, signal-to-noise ratio (SNR), and data readout limitations. The design of short-duration excitation pulses is an important topic and the focus of our work. One may show that RF excitation pulse design, under certain conditions, involves choosing to deposit energy in a continuous, 3-D, Fourier-like domain (“excitation k-space”) in order to form some desired excitation in the spatial domain. Energy may only be deposited along a 1-D contour, and there are ...

• Type: Conference
• Year: 2008
• Where: CISS
• Authors: Adam C. Zelinski, Vivek K. Goyal, Elfar Adalsteinsson, Lawrence L. Wald
• Keywords: CISS 2008, Excitation Pulse, Excitation Pulse Design, Information Management, Short-duration Excitation Pulses