Quantitative short echo-time 1H LASER-CSI in human brain at 4 T.
A novel short echo-time (1)H chemical shift imaging (CSI) pulse sequence is presented that incorporates localization by adiabatic selective refocusing (LASER) for FOV-reduction, k-space weighted averaging and macromolecule subtraction, to obtain quantitative concentration measurements of N-acetyl-aspartate, glutamate, glucose, myo-inositol, creatine and choline using a nominal voxel size of 0.56 cm(3). A comparison of spectral quality and metabolite concentration measurements was made between LASER-CSI and LASER-single voxel spectroscopy (SVS) in a region of homogeneous parietal white matter (N = 8). No significant differences were found in linewidths, signal-to-noise ratios or the effectiveness of the macromolecule subtraction between SVS and CSI. Water suppression was 45% more effective in SVS than in CSI (p < 0.05). A linear regression of all paired metabolite measurements resulted in a slope = 1.01 +/- 0.03 (r(2) = 0.73). LASER-CSI concentration measurements of N-acetyl-aspartate, glutamate, glucose, myo-inositol, creatine and choline were in agreement (within standard deviations) with LASER-SVS measurements. LASER-CSI is, therefore, a viable and attractive option for future (1)H CSI investigations.
McNab
Jennifer A
JA
Department of Medical Biophysics, University of Western Ontario, ON, Canada.
Bartha
Robert
R
D000328:Adult; D001921:Brain / Q000033:anatomy & histology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007834:Lasers; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D012016:Reference Values