Now that we know how to produce an NMR signal and get tissue-specific information from protons, how can we determine where the signal is coming from ?
To localize the voxels (single volume elements containing protons), spatial information needs to be encoded into the NMR signal.

Three steps are required :

  • First of all, the desired slice must be selected
  • Then, spatial information is encoded along the rows
  • Finally, spatial information is encoded along the columns

Decoding of spatial information, included in the NMR signal as modifications of frequency and phase, is performed by an inverse Fourier Transform (see chapter 4).