Table 1.
Main parameters of the SPEN and EPI acquisitions and processing used in the various scans presented in this study.
| Parameters | Full brain SE-EPI | Full brain SPEN | Cerebellum SPEN | Olfactory bulb SPEN (3D) | Olfactory bulb development SPEN (2D) |
|---|---|---|---|---|---|
| Repetition time (ms) | 1,000 | 1,000 | 1,000 | 1,000 | 1,000 |
| Echo Time (ms) | 29.47 | 39.57 | 37.30 | 36.15 | 35.18 |
| Acquisition time | 1 h 57 min | 1 h 57 min | 2 h 2 min | 1 h 59 min | 1 h 10 min |
| Interleaved segments | 10 | 5 | 2 | 2 | 5 |
| Averaged scans | 1 | 2 | 4 | 4 | 16 |
| Double sampling | Yes | No | No | No | No |
| Field of View (mm) | 15*20*5.4$ | 15*17*5.4 | 8*5*4 | 8*5*5 | 15*13*0.3 |
| Matrix size | 200*225*54 | 200*200*54 | 130*68*54 | 120*64*64 | 256*200*2 |
| Regridded readout points | 146 | 155 | 105 | 95 | 195 |
| Digital resolution (μm) | 103*89*100 | 97*85*100 | 76*74*74 | 84*78*78 | 77*65*300 |
| Readout bandwidth (kHz) | 500 | 500 | 250 | 250 | 500 |
| 2nd dimension (Phase, SPEN) bandwidth—kHz | 12.5 | 13.5 | 3.96 | 5.86 | 11.7 |
| SPEN's time-bandwidth product | N/A | 120 | 35 | 45 | 120 |
| Chirp duration (ms) | N/A | 8.88 | 8.84 | 7.68 | 10.24 |
| Diffusion directions | 12 | 12 | 16 | 13 | 23 |
| b-values (s/mm2) | 700 | 700 | 700 | 700 | 950 |
| Diffusion gradient strength (mT/m) | 666 | 666 | 666 | 666 | 764 |
| Diffusion gradient duration (ms) | 2 | 2 | 2 | 2 | 2 |
| Intergradient delay (ms) | 7 | 7 | 7 | 7 | 7.2 |
| Slice selection gradient (mT/m) | 8.6 | 8.6 | 9.4 | 11.7 | 156.6 |
| FWHH (localized shimming, in Hz, ±10 Hz #) | 45 | 45 | 70 | 45 | 50 |
| Denoising kernel | 3*3 | 8*8 | 2*2 | 2*2 | 2*2 |
| Average SNR of b0 image (±10%#) | 45 | 21 | 32 | 25 | 21 |
$
EPI's FOV along the blipped dimension had to be increased vis-à-vis SPEN's to avoid folding; the number of acquisition points was increased accordingly to keep equivalent spatial resolutions.
#
Errors correspond to standard deviations through a series of measurements.