Fast Spin-Echo Imaging
A fast spin echo imaging sequence is a multi-echo spin-echo sequence where different parts of k-space are recorded by different spin-echoes. For example we might have a four echo spin-echo sequence with a TE of 15 ms. The k-space will be divided into four sections. The first echo is used to fill the central part, lines 96-160, of k-space. The second echo is used for lines 64-96 and 160-192. The third echo fills lines 32-64 and 192-224. The last echo fills lines 1-32 and 224-256 of k-space. There are some problems with the steps between the parts of k-space, but since there is little data in these regions the steps can be corrected for. The benefit of the technique is that a complete image can now, as was shown in this example, be recorded in one fourth of the time.