Table 4.

Accuracies (root-mean squared error) determined through simulation over 20 000 independent trials in a water∕fat signal at a water SNR of 20. The accuracy of chemical shift is within 0.01 ppm and that of amplitude is within 1% RMSE for ETLs of 4–16. At ETL≤6, the RMSE for both $T_2^{*}$ values is high, especially for the longer $T_2^{*}$ peak (water).

No. of Echoes	Water PRF (ppm)	Water T2* (% error)	Water amplitude (% error)	Fat PRF (ppm)	Fat T2* (% error)	Fat amplitude (% error)
4	8.28×10−3	42.1	0.425	7.70×10−3	16.6	0.932
5	6.74×10−3	38.4	0.322	6.60×10−3	0.426	0.785
6	4.69×10−3	6.52	0.227	4.7×10−3	0.347	0.478
7	2.71×10−3	0.474	0.136	2.7×10−3	0.302	0.281
8	2.1×10−3	0.223	0.106	2.1×10−3	0.263	0.219
12	4.70×10−4	0.113	3.95×10−2	4.84×10−4	0.166	8.87×10−2
16	1.79×10−4	8.02×10−2	2.93×10−2	2.05×10−4	0.131	7.15×10−2