TABLE 1.
Fitting results for the water Z‐spectra averaged for all subjects and presented for all 3 B1 values
| Water Z‐spectra multi‐pool fitting results | B1 = 0.4 µT | B1 = 0.9 µT | B1 = 2.0 µT |
|---|---|---|---|
| Amplitude | |||
| Direct saturation | 0.93 ± 0.006 | 0.69 ± 0.018 | 0.38 ± 0.022 |
| MT effect | 0.00 ± 0.000 | 0.24 ± 0.015 | 0.14 ± 0.052 |
| Amines | 0.02 ± 0.003 | 0.05 ± 0.011 | 0.11 ± 0.014 |
| Amides | 0.03 ± 0.003 | 0.04 ± 0.012 | 0.04 ± 0.010 |
| Hydroxyl | 0.01 ± 0.010 | 0.03 ± 0.017 | 0.08 ± 0.015 |
| NOE | 0.06 ± 0.006 | 0.08 ± 0.004 | 0.10 ± 0.004 |
| Zbase | 0.94 ± 0.010 | 1.00 ± 0.007 | 0.69 ± 0.045 |
| MT + (1 − Zbase) | 0.06 | 0.24 | 0.45 |
| FWHM [ppm] | |||
| Direct saturation | 1.15 ± 0.056 | 2.07 ± 0.138 | 2.54 ± 0.118 |
| MT effect | 55.00 ± 0.000 | 55.00 ± 0.000 | 55.00 ± 0.000 |
| Amines | 1.07 ± 0.196 | 1.98 ± 0.374 | 3.08 ± 0.472 |
| Amides | 2.36 ± 0.366 | 2.06 ± 0.413 | 3.00 ± 0.000 |
| Hydroxyl | 1.39 ± 0.638 | 1.66 ± 0.973 | 1.27 ± 0.226 |
| NOE | 3.22 ± 0.242 | 5.00 ± 0.000 | 4.97 ± 0.065 |
| Offset from water [ppm] | |||
| Direct saturation | −0.07 ± 0.032 | −0.04 ± 0.037 | −0.20 ± 0.000 |
| MT effect | −2.30 ± 0.000 | −2.30 ± 0.000 | −2.30 ± 0.000 |
| Amines | 2.23 ± 0.095 | 1.90 ± 0.195 | 1.98 ± 0.054 |
| Amides | 3.53 ± 0.178 | 3.40 ± 0.218 | 3.81 ± 0.155 |
| Hydroxyl | 0.75 ± 0.088 | 0.74 ± 0.070 | 0.70 ± 0.015 |
| NOE | −3.52 ± 0.070 | −2.96 ± 0.158 | −2.31 ± 0.069 |
Fitting results approaching the predefined fit range boundaries are displayed in grey, fixed values in red. Lorentzian amplitudes: 0 means no effect, 1 full saturation. The amplitude of the NOE effect increases with B1, as well as the amplitude of the exchange effects from hydroxyl and amines. The exchange effect of amides remains fairly constant. For the highest B1, strong overall reduction of the signal was detected. The FWHM of the direct water saturation increases from 1.2 to 2.5 ppm. The MT effect should be judged in combination with Zbase (as shown in the lowest row of amplitude values).