Solid-state NMR imaging methods. part I: strong field gradients

Abstract

NMR imaging has been shown to be a viable and useful approach to exploring spatial chemistry and molecular dynamics of a wide range of materials. NMR provides image contrast which is fundamentally different from that of other methods. The principles of NMR imaging and spatial information applicable to materials are reviewed, and examples of current development are given. Of fundamental importance for spatial resolution in solid-state imaging are the relationships between NMR linewidth, image resolution, signal-to-noise ratio, and measuring times. The principles of NMR with spatial resolution by frequency and phase encoding are introduced. The NMR line-broadening effect characteristic for dipolar and quadrupolar solids or quasisolids can be surpassed by strong field gradients or line-narrowing methods. Correspondingly, one class of NMR imaging methods uses stray fields, strong oscillatory gradients, or multiple-quantum coherences evolution. It is discussed in Part I. In Part II the basic principles of the second class using line-narrowing methods by magic-echoes, magic-angle sample spinning, multiple-pulse excitation, and magic-angle rotating frame techniques are presented. The possibility of recording spatially resolved spectroscopic parameters by these methods is also addressed. © 2000 John Wiley & Sons, Inc. Concepts Magn Reson 12: 188–206, 2000