The use of immobilized ferrite to enhance the depth selectivity of <i>in vivo</i> surface coil NMR spectroscopy

Abstract

Ferrite particles immobilized on a flexible support and arranged in a specific pattern will produce localized gradients in the homogeneous B0 magnetic field. The screening gradients are strong enough to cause inhomogeneous broadening of the NMR signals arising from the region of a specimen which is adjacent to the ferrite particles. This technique allows improvement of the depth selectivity in non-invasive surface coil NMR spectroscopy while optimizing both the signal-to-noise ratio and the data acquisition time of in vivo NMR experiments. The ferrite screen method also facilitates the routine application of high resolution NMR pulse sequences to in vivo experiments. The technique is readily implemented without special hardware or software and displays a great versatility in the size, shape and depth of the screening effect.