Compensation for spin-lock artifacts using an off-resonance rotary echo in T1ρoff-weighted imaging
✍ Scribed by Walter R.T. Witschey; Arijitt Borthakur; Mark A. Elliott; Eric Mellon; Sampreet Niyogi; Chenyang Wang; Ravinder Reddy
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 589 KB
- Volume
- 57
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Abstract
The origin of image artifacts in an off‐resonance spin‐locking experiment is shown to be imperfections in the excitation flip angle. A pulse sequence for off‐resonance spin locking is implemented that compensates for imperfections in the excitation flip angle through an off‐resonance rotary echo. The off‐resonance rotary echo alternates the frequency offset and phase of the RF transmitter during two spin‐locking pulses of equal duration. The underlying theory is detailed, and MR images demonstrate the effectiveness of the technique in agarose gel phantoms and in in vivo human brain at 3T. Magn Reson Med 57:2–7, 2007. © 2006 Wiley‐Liss, Inc.