Detection of cerebral metabolites by single‐voxel‐based PRESS and COSY techniques at 3T

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Abstract
Purpose 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. Materials and 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 × 3 × 3 cm3) and a measurement time of ∼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. Conclusion 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. J. Magn. Reson. Imaging 2007;26:405–409.