Coefficients of variation (%) of metabolite ratios obtained from the phantom and from the posterior cingulate voxel in the cognitively normal elderly subjects, at 1.5 and 3 T
| Ratio | TE (ms) | Phantom (n = 81) | Posterior Cingulate Voxel (n = 41) | ||
|---|---|---|---|---|---|
| 1.5 T | 3 T | 1.5 T | 3 T | ||
| NAA/Cr | 135 | – | – | 7 | 9 |
| Cho/Cr | 135 | – | – | 12 | 13 |
| NAA/Cr | 30 | 1.4* | 1.9 | 5 | 6 |
| Cho/Cr | 30 | 1.4 | 1.3 | 10† | 14 |
| MI/Cr | 30 | 2.8* | 5.1 | 11 | 14 |
| NAA/MI | 30 | 3.6* | 5.5 | 13 | 14 |
| Glu + Gln/Cr | 30 | – | – | – | 16 |
| Glu/Cr | 30 | – | 5.3 | – | 15 |
* P < .01 for comparison of coefficients of variation from the phantom at 1.5 with those at 3 T by using a two-sample t statistic approximation.
† P < .05 for comparison of coefficients of variation from the posterior cingulate voxel at 1.5 with those at 3 T by using a two-sample t statistic approximation.