Depth selective NMR spectroscopy by using a surface coil.

A method to perform depth selective NMR spectroscopy with a surface coil has been devised. Using the heterogeneous B sub 1 field distribution generated by a surface coil, all the spins are excited by a preparation pulse sequence to become saturated through T sub 2 decay except the spins in a selected region. The z- magnetization of these spins in the selected region are kept intact during this period and then excited by suitable observation pulses. The selection of the region or the depth from the surface of the coil (1 dimensional selection) is made by choosing a suitable pulse width with which the B sub 1 field in the selected region induces 90degree rotation of the spins and in the preparation pulse sequence pulses are arranged to rotate these spins in the region to come back to the z direction to avoid T sub 2 decay. Some phantom samples are used to test the method.