HADAMARD NMR IMAGING WITH SLICE SELECTION

Stochastic NMR imaging is one of the less common NMR imaging technique s, Nevertheless, stochastic rf excitation is characterized by some rem arkable features: the rf excitation power is at least two orders of ma gnitude lower in comparison to conventionally pulsed NMR imaging schem es.(1-3) Thus, the technique is of interest for imaging of large objec ts, The systematic noise inherent in images obtained with random noise excitation has been eliminated by using pseudorandom noise together w ith Hadamard transformation for data evaluation, Data acquisition time s are comparable to those of ultrafast imaging techniques. For slice s election, z magnetization is destroyed outside the slice region with s pecially designed low power pulses, Thus, gradient switching times are only limited by T-1 and not T-2. Images are reconstructed by the bac kprojection algorithm. We have set up a stochastic imaging procedure o n a conventional Bruker MSL 300 spectrometer, and have drawn a compari son between images obtained by the pseudorandom noise excitation and b y conventional Fourier imaging. Copyright (C) 1996 Elsevier Science In c.