B1-INSENSITIVE HADAMARD SPECTROSCOPIC IMAGING TECHNIQUE

A B1-insensitive Hadamard spectroscopic imaging technique for multivolume localization is presented and tested experimentally. This technique can give localized spectroscopic information from n regions of interest by n scans using homogeneous or inhomogeneous coils, such as surface coils. The B1 insensitivity is achieved by using RF pulses which invert spins adiabatically at several well-defined slices simultaneously. We show how any adiabatic pulse can be modified such that it can invert spins at one or several desired frequency bands simultaneously. With the modified adiabatic pulses, B1-insensitive Hadamard spectroscopic imaging experiments of any order can be performed. © 1991.