Robert Daniel O'Connell1, Steen Moeller1,
Djaudat Idiyatullin1, Curt Corum1, Michael Garwood1
1Center for Magnetic Resonance
Research,
A
comparison is made between infinitely short RF pulses (delta), hard pulses
and SWIFT using the Ernst energy equation and Bloch simulations. Simulation
results are reported for each pulse sequence for on- and off-resonance
systems at T1=T2. The SWIFT, delta pulse, and long T1,2 on-resonance
hard-pulse sequences are described by the Ernst equations. On-resonance hard
pulses have signal energy loss for short T1,2. Off-resonance hard pulses are
not described by the Ernst equations. In addition to being unaffected by
resonance offsets, for any flip angle the SWIFT sequence results in having a
signal energy peak at shorter T1,2 than the other sequences.
Keywords