TABLE 2.
Non‐aqueous component parameters T2,min and chemical shift (δ) found by open fits to averaged WM and GM signals for all D2O (“D”) samples, as well as mean value and SD per tissue type
| Sample | T2,min,U [μs] | T2,min,S [μs] | δU [ppm] | δS [ppm] | |||||
|---|---|---|---|---|---|---|---|---|---|
| WM | 1Ds | 6.76 | (0.16) | 92.1 | (0.74) | 1.02 | (0.02) | 2.10 | (0.01) |
| 2Ds | 4.94 | (0.06) | 122 | (0.46) | 0.85 | (0.01) | 1.96 | (0.00) | |
| 1Dz | 5.53 | (0.16) | 88.1 | (0.48) | 1.30 | (0.02) | 2.06 | (0.01) | |
| 2Dz | 4.71 | (0.11) | 108 | (0.51) | 1.10 | (0.01) | 2.25 | (0.00) | |
| Mean | 5.48 | 102 | 1.07 | 2.09 | |||||
| SD | 0.92 | 15.5 | 0.18 | 0.12 | |||||
| GM | 1Ds | 10.3 | (0.19) | 157 | (1.28) | 0.77 | (0.02) | 2.47 | (0.00) |
| 2Ds | 8.88 | (0.08) | 219 | (1.07) | 0.10 | (0.01) | 2.20 | (0.00) | |
| 1Dz | 10.6 | (0.49) | 152 | (3.88) | 0.69 | (0.05) | 2.35 | (0.01) | |
| 2Dz | 7.92 | (0.34) | 155 | (2.35) | 0.75 | (0.04) | 2.51 | (0.01) | |
| Mean | 9.42 | 171 | 0.58 | 2.39 | |||||
| SD | 1.25 | 32.2 | 0.32 | 0.14 | |||||
Note: Standard errors obtained by propagation of the noise variance in the underlying images are given in parenthesis. T2,min is longer in GM than WM, but the signal components each exhibit a clear range of decay constant irrespective of tissue type. In WM and partly in GM, there is more variation between the two tissue blocks (“1” and “2”) than between fresh (“s”) and frozen (“z”) samples. This indicates that anatomical location affects the detectable signal components to some degree while freezing has little impact. The GM components found in sample 2Ds deviate somewhat from those found in the other samples, which is considered to be a manifestation of instability in the open fits. GM fits are generally less stable than WM fits due to the lower signal level.