Table 1 Image acquisition parameters, measured values of noise as well as the signal and SNR of the totally illuminated area (Stotal), and the segmented high intensity (Shigh) and low intensity parts (Slow) (cf. Figure 3). The fourth row presents the time required for acquiring the number of k-space lines after one block of illumination. All images were acquired with a FoV of 9 × 9 mm2 (cf. Figure 3) and a four-fold oversampling, i.e. four-fold number of k-space lines as compared to the actual resolution. The first two echoes of each echo train were not used for image encoding to reduce the impact of B0 and B1 artifacts.
Figure | 3a/e | 3b/f | 3c/g | 3d/h |
|---|---|---|---|---|
Image acquisition parameters | ||||
Actual resolution in plane (FoV 9 × 9 mm2) | 9 × 9 1 mm2/pix | 17 × 17 (0.53)2 mm2/pix | 17 × 17 (0.53)2 mm2/pix | 23 × 23 (0.39)2 mm2/pix |
Acquisition (per illumination) | Full image (36 k-space lines) | Full image (68 k-space lines) | Full image/4 (17 k-space lines) | Full image/2 (46 k-space lines) |
Illumination | 1 × 4 s | 1 × 4 s | 4 × 4 s | 2 × 4 s |
Acquisiton time per illumination | 36 × 4 ms + 8 ms = 152 ms | 68 × 4 ms + 8 ms = 280 ms | 17 × 4 ms + 8 ms = 76 ms | 46 × 4 ms + 8 ms = 192 ms |
Averages | 8 | 16 | 16 | 16 |
Signal-to-noise ratio (SNR) | ||||
Noise/μV | 2.73 × 10–4 | 4.27 × 10–4 | 5.0 × 10–4 | 6.5 × 10–4 |
Mean Stotal/μV SNRtotal | 1.68 × 10–3 6.15 | 2.02 × 10–3 4.73 | 3.07 × 10–3 6.14 | 2.77 × 10–3 4.26 |
Mean Shigh/μV SNRhigh | 3.01 × 10–3 11.03 | 3.78 × 10–3 8.85 | 5.05 × 10–3 10.1 | 4.68 × 10–3 7.2 |
Mean Slow/μV SNRlow | 1.48 × 10–3 5.42 | 1.79 × 10–3 4.19 | 2.99 × 10–3 5.98 | 2.65 × 10–3 4.0 |
Signalmin/μV (blue) Signalmax/μV (red) | 6.39 × 10–5 3.17 × 10–3 | 1.71 × 10–5 3.96 × 10–3 | 2.04 × 10–5 5.481 × 10–3 | 6.14 × 10–5 5.24 × 10–3 |
