Three-dimensional J-resolved H-1 magnetic resonance spectroscopic imaging of volunteers and patients with brain tumors at 3T.
A method that combines two-dimensional (2D) J-resolved spectroscopy with three spatial dimension magnetic resonance spectroscopic imaging (MRSI) is introduced to measure J-coupled metabolites of glutamate (Glu), glutamine (Gln), myo-Inositol (mI), and lactate (Lac) in the brain and to simultaneously obtain T(2) values of choline (Cho), creatine (Cr), and N-acetyl aspartate (NAA). Relatively few points in the t(1) dimension (six echo times) and a flyback echo-planar trajectory were incorporated in the acquisition to speed up the total acquisition time so that it was within a clinically feasible range (23 min). Data obtained using GAMMA software simulations and from phantoms have shown that the (4)CH(2) resonances of Glu can be separated from Gln at 2.35 ppm in TE-averaged spectra. Results from phantoms, six normal volunteers, and four patients demonstrated good signal-to-noise ratio (SNR). The J cross-peaks from the methyl group of Lac were visualized in the 2D spectra from the phantom and the glioma patient, and could be quantified from the spectra at J = +/-4.17 Hz. This technique also enables the evaluation of the changes in metabolite T(2). Compared with the values in normal white matter, the T(2) values of Cho and Cr were statistically significantly increased in regions of glioma.
Li
Yan
Y
University of California, San Francisco/University of California, Berkeley Joint Graduate Group in Bioengineering, San Francisco, California 94143-2532, USA. yan.li@radiology.ucsf.edu
Chen
Albert P
AP
Crane
Jason C
JC
Chang
Susan M
SM
Vigneron
Daniel B
DB
Nelson
Sarah J
SJ
D001932:Brain Neoplasms / Q000473:pathology*; D016022:Case-Control Studies; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*