Hui Liu1, Gerald Matson1,2
1CIND, Veterans Affairs Medical Center,
San Francisco, CA, United States; 2Pharmaceutical Chemistry,
University of California, San Francisco, San Francisco, CA, United States
Although
high-field MRI offers increased signal-to-noise (S/N), the non-uniform
tipping produced by conventional RF pulses leads to spatially dependent
contrast and sub-optimal S/N, thus complicating the interpretation of the MR
images. The aim of this research was
to develop broadband RF pulses with immunity to B1 inhomogeneity. To accomplish
this, we developed an optimization routine based on optimal control theory to
design RF pulses with a desired range of immunity to B1 inhomogeneity and to
resonance offset. The resulting pulses
were more efficient than analogous pulses in the literature. These pulses have promise for certain MRI
experiments at high field.