Table 2.
Comparison of Different Acquisition Schemes (Reduction Factor R, # of Echoes M, Echo Combination Scheme) in Terms of TNAV, SFNR, and SNR
| Acquisition scheme | TNAV | SFNR | SNR | |
|---|---|---|---|---|
| (a) | R = 1, M = 1, TE = 50 ms | 11,594 ± 2182a 1.00b | 66.65 ± 4.43a 1.00b | 57.04 ± 3.69a 1.00b |
| (b) | R = 2, M = 1, TE = 21.1 ms | 6486 ± 2555 0.56 | 80.19 ± 4.43 1.20 | 63.50 ± 3.78 1.11 |
| (c) | R = 2, M = 1, TE = 41.1 ms | 8844 ± 2773 0.76 | 58.67 ± 3.06 0.88 | 48.30 ± 2.59 0.85 |
| (d) | R = 2, M = 1, TE = 61.1 ms | 8769 ± 2624 0.76 | 43.99 ± 2.33 0.66 | 37.13 ± 1.85 0.65 |
| (e) | R = 2, M = 3, Echo summation | 13,691 ± 3522 1.18 | 92.53 ± 6.00 1.39 | 77.26 ± 6.18 1.35 |
| (f) | R = 2, M = 3, T2*-weighted echo combination | 13,855 ± 3518 1.19 | 86.81 ± 5.54 1.30 | 74.77 ± 4.47 1.31 |
| (g) | R = 3, M = 1, TE = 23.4 ms | 4225 ± 1726 0.36 | 57.81 ± 3.57 0.87 | 45.64 ± 2.43 0.80 |
| (h) | R = 3, M = 1, TE = 36.7 ms | 5395 ± 2031 0.47 | 47.33 ± 2.63 0.71 | 37.77 ± 1.71 0.66 |
| (i) | R = 3, M = 1, TE = 50 ms | 5636 ± 2122 0.49 | 39.06 ± 1.99 0.59 | 31.59 ± 1.37 0.55 |
| (j) | R = 3, M = 1, TE = 63.3 ms | 5393 ± 2071 0.47 | 32.45 ± 1.58 0.49 | 26.63 ± 1.04 0.47 |
| (k) | R = 3, M = 4, Echo summation | 10,842 ± 3019 0.94 | 75.83 ± 6.26 1.14 | 64.08 ± 4.53 1.12 |
| (l) | R = 3, M = 4, T2*-weighted echo combination | 10,913 ± 3043 0.94 | 72.64 ± 5.86 1.09 | 62.48 ± 3.67 1.10 |
a
Average SFNR and SNR ± standard deviation over all subjects and sessions are shown in this table.
b
Values in the second line of each acquisition scheme are relative to the acquisition with R = 1, M = 1.