Sebastian Schmitter1, Soeren Johst2,
Michael Bock2, Kamil Ugurbil1, Pierre-Francois van de
Moortele1
1University of Minnesota, Center for
Magnetic Resonance Research, Minneapolis, MN, United States; 2German
Cancer Research Center, Heidelberg, Germany
It
has been shown that successful Time-of-flight (TOF) images can be obtained at
7T benefiting from higher SNR and longer tissue T1. However, because of SAR
constraints, magnetization transfer pulses that are used at 1.5T/3T cannot be
used at 7T, saturation pulses are often skipped and the flipangle is limited.
These issues can be addressed using the VERSE principle to decrease SAR.
However, VERSE pulses are more sensitive to δB0. Here, we investigate in
simulations and in vivo the impact of off-resonance frequencies on RF
excitation profile of ramp shaped RF pulses (TONE) when applying VERSE at 7T.
Keywords