Premium
Alternating repetition time balanced steady state free precession
Author(s) -
Leupold J.,
Hennig J.,
Scheffler K.
Publication year - 2006
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20790
Subject(s) - steady state free precession imaging , flip angle , nuclear magnetic resonance , sensitivity (control systems) , pulse (music) , chemistry , magnetization , resonance (particle physics) , steady state (chemistry) , phase (matter) , atomic physics , physics , magnetic resonance imaging , optics , magnetic field , detector , medicine , quantum mechanics , electronic engineering , engineering , radiology , organic chemistry
A novel balanced SSFP technique for the separation or suppression of different resonance frequencies (e.g., fat suppression) is presented. The method is based on applying two alternating and different repetition times, TR 1 and TR 2 . This RF scheme manipulates the sensitivity of balanced SSFP to off‐resonance effects by a modification of the frequency response profile. Starting from a general approach, an optimally broadened stopband within the frequency response function is designed. This is achieved with a TR 2 being one third of TR 1 and an RF‐pulse phase increment of 90°. With this approach TR 2 is too short (∼1 ms) to switch imaging gradients and is only used to change the frequency sensitivity. Without a significant change of the spectral position of the stopband, TR 1 can be varied over a range of values (∼2.5–4.5 ms) while TR 2 and phase cycling is kept constant. On‐resonance spins show a magnetization behavior similar to balanced SSFP, but with maximal magnetization at flip angles about 10° lower than in balanced SSFP. The total scan time is increased by about 30% compared to conventional balanced SSFP. The new technique was applied on phantoms and volunteers to produce rapid, fat suppressed images. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.