INTERPRETATION OF DW-NMR DATA - DEPENDENCE ON EXPERIMENTAL CONDITIONS

This review examines the effect of experimental conditions on the data obtainable from diffusion weighted NMR experiments. The origin and fo rms of the Stejskal-Tanner experiment are presented, and the relative merits of bipolar to monopolar diffusion weighting gradient pulses are discussed, as are those of spin-echo and stimulated-echo weighting sc hemes. The short pulse Stejskal-Tanner experiment as required for q-sp ace imaging is described, Criteria for successful diffusion weighted i maging are given, and current strategies for diffusion weighted imagin g are evaluated against these, The range of biological objects accessi ble to diffusion weighted NMR is summarized, together with the associa ted experimental limitations. In the final section the dependence of d iffuson weighted NIL NMR data on diffusion time and b-value range is e xamined, and the relationship between apparent restricted diffusion an d the size of the extracellular space is demonstrated.