Table 1:

SNR and metabolite ratios

SNRROI (%)SNRvoxel (%)SNRtheory (%)Scan Time (%) (24 × 24 Scan)Cho/NAACr/NAA
ETL = 11001001001000.390.35
ETL = 2849071510.380.31
ETL = 6546248230.300.27
SENSE, ETL = 2505138150.370.33
SENSE, ETL = 632322980.420.33
  • NOTE:—SNR indicates signal intensity-to-noise ratio; ETL, echo-train length; SENSE, sensitivity encoding; Cho, choline; Cr, creatine; NAA, N-acetylaspartate. SNR, averaged over SNRNAA, SNRCr, SNRCho, was averaged once over a region of interest (ROI) containing 105 voxels and once only for the voxel depicted in FIg 4. SNRtheory gives only the theoretical SNR reduction with the square root of total scan time. The metabolite ratios are given for the voxel depicted in Fig 4 and show the variability over the different acquisition techniques.