Double-echo multislice proton spectroscopic imaging using Hadamard slice encoding.

Simultaneous multislice proton spectroscopic imaging (SI) is presented using a pulse sequence with multifrequency selective RF excitation and Hadamard encoding in the slice direction, and conventional Fourier phase encoding in the in-plane directions. Double-echo data acquisition is used to increase the spectral information of the experiment. Tests on a phantom demonstrate the quality of the slice selection. Results of in vivo measurements of the healthy rat brain show that spectra with a high signal-to-noise ratio can be acquired from four slices within 32 min. The measurements were performed at 4.7 T using a field of view of 32 x 32 mm2, a slice thickness of 3 mm, and a voxel size of 12 microliters. The proposed method is a useful alternative to sequential multislice SI and 3D SI. Furthermore, it is possible to combine sequential and simultaneous multislice SI.