Detection of cerebral metabolites by single-voxel-based PRESS and COSY techniques at 3T.
OBJECTIVE
To compare point-resolved spectroscopy (PRESS) and localized two-dimensional (2D) correlated spectroscopy (L-COSY) in the detection of cerebral metabolites in humans on a clinical scanner at 3T and to estimate their respective inter- and intrasubject variances.


METHODS
Measurements were made on nine healthy subjects to assess intersubject variance, and daily on a single subject over a period of seven days to assess intrasubject variance. All L-COSY measurements were performed with a voxel size of 27 mL (3 x 3 x 3 cm(3)) and a measurement time of approximately 34 minutes in the occipitoparietal lobe of the brain. Relative metabolite concentrations were estimated with respect to N-methyl creatine.


RESULTS
While the sensitivity of PRESS is twice that of L-COSY, the greater spectral resolution offered by L-COSY resulted in greater consistency in estimates of the concentrations of several cerebral metabolites, as indicated by a superior intraclass correlation and a significantly lower standard deviation (SD) in a matched pair intrasubject analysis.


CONCLUSIONS
Our pilot results demonstrate that L-COSY is an effective approach for resolving cerebral metabolites, and demonstrates a lower coefficient of variance (CV) than the conventional 1D localized spectroscopic approach using LC Model for quantification.
Velan
S Sendhil
SS
Center for Advanced Imaging and Radiology, West Virginia University, Morgantown, West Virginia 26506, USA. svelan@hsc.wvu.edu
Lemieux
Susan K
SK
Raylman
Raymond R
RR
Boling
Warren
W
Hobbs
Gerald R
GR
Spencer
Richard G
RG
Sridhar
Rajagopalan
R
Kuppusamy
Periannan
P
Thomas
M Albert
MA
D000328:Adult; D000465:Algorithms; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D001931:Brain Mapping / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008280:Magnetics; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013053:Spectrophotometry / Q000379:methods