| Magnetic Resonance Spectroscopy (MRS) is a powerful tool to non-invasively monitor metabolites in vivo. In most in vivo applications, the region of interest (ROI) for spectroscopy is only a small subset of a radio-frequency (RF) coil's active volume. To acquire signal from only the ROI, single voxel spectroscopy localization methods are used. Presented in this work is a novel localization method based on a train of adiabatic full passage RF pulses. Like a Carr-Purcell refocusing train, this sequence is composed of several closely spaced inversion pulses, however, these pulses are also spatially selective to hew out a single voxel. This technique's similarity to Carr-Purcell trains gains it the advantages of reduced J-modulation and retarded transverse magnetization (T2) relaxation. The broad bandwidth adiabatic pulses produce insensitivity to variations in RF field homogeneity and better localization of chemically shifted metabolites. Finally, the fact that localization is complete in a single repetition reduces this technique's sensitivity to patient motion. Various magnetization preparation modules used with the sequence are described including water suppression and heteronuclear techniques. Also, to facilitate a particular application, breast MRS, techniques for high-field slab-selective 3D imaging are presented. |
