It is SAR echo signal secho(t r, t a ) contaminated by RFI signal sRFI(t r, t a ) and system noise sNoise(t r, t a ): s ( t r, t a ) = s echo ( t r, t a ) + s RFI ( t r, t a ) + s Noise ( t r, t a ) (1).
A 2D gradient echo (T 2*-weighted) sequence was used with the following parameters: TR=500 ms; TE=30 ms; FOV 30 mm; 128 × 128 voxels; 11 slices; 1 mm slice thickness; and 16 averages.
A 2D spin echo (T 2-weighted) sequence was also used: TR=1500 ms; TE=120 ms; FOV 30 mm; 128 × 128 voxels; 7 slices; slice thickness 1 mm; 16 averages.
A 3 Tesla MR head scanner (Magnetom Allegra, Siemens, Erlangen, Germany) was used to acquire gradient echo T 2 * -weighted echo-planar images (EPI) with blood oxygen level dependent contrast (time echo = 30 ms, time repetition = 1.43 s, flip angle = 70°, slice tilt = 30°, z-shim gradient prepulse = −1 mT/m ms).
In Figure 5, the maximum correlation coefficient of the first echo (namely echo at t = 0) and other echoes.
Figure 5 The maximum correlation coefficient of echo at t = 0 and other moments.
Figure 7 The maximum the maximum correlation coefficient of echo at t = 0 and other moments.
When there was a lack of good symmetry in each target scattering point, if only seven scattering points were selected, such as the ①②③⑤⑥⑦⑨ in Table 1, the maximum correlation coefficient of echo at t = 0 and other moments were shown in Figure 7.
Imaging parameters were as follows: echo time (T E ) = 3.2 ms., repetition time (T R ) = 7100 ms, flip angle = 8.0°, field of view (FoV) = 240 mm, and voxel size = 1.0 × 1.03 × 1.0 mm.
Amplitude and phase images were acquired with a gradient echo technique at 7.0 T (5 echoes TE=5/10/15/20/25/30 ms).
And in an echo of Ted's unfortunate accidental Hitler moustache, a glitch on the BBC's big screen in Media City added a perfect black square to the top lip of Nigel Farage.
