Application of a Constant Pulse Width VERSE Design to a Silver-Hoult Inversion Recovery Pulse for T1Flair
Gai N, Zur Y
The RF power deposited at high fields scales roughly as the square of the B0 field. The variable-rate selective excitation (VERSE) technique reduces the SAR deposited by reshaping the RF and slice-select gradient pulses. A desirable feature is to maintain the pulse width of the original pulses constant (mainly for contrast purposes). We have devised and implemented an algorithm based on modeling the scaled waveforms as the Fermi function. The algorithm is applied to a SAR intensive Silver-Hoult inversion recovery pulse used for a T1-weighted fast spin echo inversion recovery sequence. Results show considerable reduction in SAR deposition and/or slice coverage at 3T, especially when used in conjuction with VERSE'd slice excitation and refocusing pulses.