Table 1.
Metabolite concentrations and spectral line widths of the aqueous phantom as well as the Cramer-Rao lower bound for spectral fits derived with three different methods as indicated
| Methoda | Metabolite concentrationb | Line width (Hz) | |||||
|---|---|---|---|---|---|---|---|
| NAA | Cho | Cr | Glu | MI | Lactate | ||
| In relation to water signal (i. u.) | |||||||
| SVS-LCM | 5.40 | 1.66 | 4.35 | 5.88 | 3.07 | 1.65 | 5.30 |
| wbMRSI | 5.57 | 1.36 | 4.36 | 5.38 | 2.64 | 2.15 | 4.73 |
| Hybrid | 26.10 | 7.31 | 20.60 | 27.70 | 17.00 | 10.20 | 4.32 |
| Known concentration (mM) | 12.5 | 3.0 | 10.0 | 12.5 | 7.5 | 5.0 | – |
| In relation to Cr | |||||||
| SVS-LCM | 1.24 | 0.38 | 1.00 | 1.35 | 0.71 | 0.38 | – |
| wbMRSI | 1.28 | 0.31 | 1.00 | 1.23 | 0.60 | 0.49 | – |
| Hybrid | 1.27 | 0.36 | 1.00 | 1.35 | 0.83 | 0.50 | – |
| Known concentration (mM) | 1.25 | 0.30 | 1.00 | 1.25 | 0.75 | 0.50 | – |
| Cramer-Rao lower bound | |||||||
| SVS-LCM | 2.0 | 3.0 | 3.0 | 5.0 | 4.0 | 14.0 | – |
| wbMRSI | 0.5 | 0.7 | 0.5 | 0.9 | 1.0 | 1.3 | – |
| Hybrid | 1.0 | 1.0 | 1.0 | 2.0 | 2.0 | 5.0 | – |
a
SVS-LCM: spectral data were scanned with single voxel spectroscopy (SVS) and analyzed with LCModel whole brain MR spectroscopic imaging (wbMRSI): data were scanned with spin-echo planar spectroscopic imaging (EPSI) and analyzed with Metabolic Imaging and Data Analysis System (MIDAS). Hybrid: data were scanned with EPSI and analyzed with LCModel
b
None of the spectral analysis methods were normalized to result in molar concentrations. All results determined as ratio to the water signal in institutional units (i.u.) or to total creatine (tCr)