This is a variable density data set.

21   interleaves
5120 samples/interleave
128x128 image

oversampled by a factor of two over 1/4 the k-space diameter.

Since the number of interleaves is odd, you can use this set to
acquire a larger FOV, and then use a partial k-space reconstruction
to eliminate the spiral artifacts, which should be imaginary, if the
primary image is real, and there are no phase errors.