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Abstract #4445

Non-Slice Selective Uniform Tipping RF Pulse Design for 3D MRI at High Field

Hui Liu1,2, Gerald B. Matson1,3

1Center for Imaging of Neurodegenerative Diseases (CIND), Veterans Affairs Medical Center, San Francisco, CA, United States; 2Northern California Institute for Research & Education, San Francisco, CA, United States; 3University of California, San Francisco,CA, United States

Although high-field MRI offers increased signal-to-noise (SNR), the non-uniform tipping produced by conventional RF pulses leads to spatially varying contrast such as a bright center, and sub-optimal S/N, thus complicating the interpretation of the MR images. The aim of this research was to develop non-slice-selective (NSS) RF pulses with immunity to B1 inhomogeneity and resonance offset for a full range of tip angles. To accomplish this, we developed an optimization routine to design RF pulses with a desired range of immunity to B1 inhomogeneity and to resonance offset. Simulations were validated by phantom tests and an in vivo human study. The resulting pulses were more efficient (in terms of length) than previous pulses in the literature. These pulses have promise for 3D MRI experiments at high field.