ANALYTICAL EXPRESSIONS FOR THE B-MATRIX IN NMR DIFFUSION IMAGING AND SPECTROSCOPY

General analytical expressions are presented for the b matrix used in diffusion NMR imaging and spectroscopy. These expressions are evaluate d in the case of a two-dimensional Fourier-transform spin-echo imaging sequence and show the effect of ''cross terms'' between gradient puls es. The diagonal and off-diagonal components of the b matrix are calcu lated for the anisotropic diffusion tenser. The proposed analysis allo ws diffusion coefficients and tensors to be determined accurately and with greater efficiency. (C) 1994 Academic Press, Inc.