High resolution spectroscopic imaging of GABA at 3 Tesla

H Zhu, RAE Edden, R Ouwerkerk… - Magnetic resonance in …, 2011 - Wiley Online Library
H Zhu, RAE Edden, R Ouwerkerk, PB Barker
Magnetic resonance in medicine, 2011Wiley Online Library
A spin echo‐based MRSI sequence was developed to acquire edited spectra of γ‐
aminobutyric acid in an entire slice. Water and lipid signals were suppressed by a dual‐
band presaturation sequence, which included integrated outer volume suppression pulses
for additional lipid suppression. Experiments in three normal volunteers were performed at 3
T using a 32‐channel head coil. High signal‐to‐noise ratio spectra and metabolic images of
γ‐aminobutyric acid were acquired from nominal 4.5 cm3 voxels (estimated actual voxel size …
Abstract
A spin echo‐based MRSI sequence was developed to acquire edited spectra of γ‐aminobutyric acid in an entire slice. Water and lipid signals were suppressed by a dual‐band presaturation sequence, which included integrated outer volume suppression pulses for additional lipid suppression. Experiments in three normal volunteers were performed at 3 T using a 32‐channel head coil. High signal‐to‐noise ratio spectra and metabolic images of γ‐aminobutyric acid were acquired from nominal 4.5 cm3 voxels (estimated actual voxel size 7.0 cm3) in a scan time of 17 min. The sequence is also expected to co‐edit homocarnosine and macromolecules, giving a composite γ‐aminobutyric acid+ resonance. The γ‐aminobutyric acid+ to water ratio was measured using a companion water MRSI scan and was found to correlate linearly with the % gray matter (GM) of each voxel (γ‐aminobutyric acid+/water = (1.5 × GM + 3.2) × 10−5, R = 0.27), with higher γ‐aminobutyric acid+ levels in gray matter compared with white. In conclusion, high signal‐to‐noise ratio γ‐aminobutyric acid‐MRSI is possible at 3 T within clinically feasible scan times. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
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