Fig. 3.

Tensor field imaging. (A) Virtual spin distribution on a square surface from –5 to 5 cm with a 0.1-cm mesh. Circles have 0.5-cm radii and are 2 cm apart from each other. (B) Standard projection/reconstruction in the presence of a strong and homogeneous magnetic field. The concomitant gradient is truncated. Notice, however, the typical star-like behavior at large radii. (C) Tensor field imaging with acquisition at the end of the interpulse interval. The sharp peak at the center (zero frequency) is caused by imperfect averaging. (D) Same as described for C but with acquisition at half the interpulse interval (see Fig. 2A). For B–D, the gradient strength was 0.06 G/cm (250 Hz/cm), the dwell time was 1 ms, and the free induction decay had 256 points. Twenty-five equally spaced angles were used covering the range of 0–180. Pulses had an amplitude of 3 G.