B1 and T1 insensitive water and lipid suppression using optimized multiple frequency-selective preparation pulses for whole-brain 1H spectroscopic imaging at 3T
✍ Scribed by Meng Gu; Daniel M. Spielman
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 489 KB
- Volume
- 61
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Abstract
A new method for the simultaneous suppression of water and lipid resonances using a series of dual‐band frequency‐selective radiofrequency (RF) pulses with associated dephasing gradients is presented. By optimizing the nutation angles of the individual pulses, the water and lipid suppression is made insensitive to a range of both T~1~‐relaxation times and B~1~ inhomogeneities. The method consists only of preparatory RF pulses and thus can be combined with a wide variety of MRSI schemes including both long and short TE studies. Simulations yield suppression factors, in the presence of ±20% B~1~ inhomogeneity, on the order of 100 for lipid peaks with three different T~1~s (300 ms, 310 ms, and 360 ms), and water peaks with T~1~s ranging from 0.8 s to 4 s. Excellent in vivo study performance is demonstrated using a 3 Tesla volumetric proton spectroscopic imaging (^1^H‐MRSI) sequence for measuring the primary brain metabolites peaks of choline (Cho), creatine (Cr), and N‐acetyl aspartate (NAA). Magn Reson Med 61:462–466, 2009. © 2009 Wiley‐Liss, Inc.