Abstract: A coil circuit comprising a multi-mode resonant gradient or RF coil circuits for imaging and spectroscopy in Nuclear Magnetic Resonance systems.

Abstract: Zonal magnification of a selected area of an image produced by Echo Planar Imaging is acheived by taking images of a defined area in the presence of a selective 180.degree. R.F. control pulse so that subsequent processing produces a magnified image of the selected area with enhanced resolution.

Abstract: A switched coil arrangement is connected in a bridge configuration of four switches S.sub.1, S.sub.2, S.sub.3 and S.sub.4 which are each shunted by diodes D.sub.1, D.sub.2, D.sub.3 and D.sub.4 so that current can flow in either direction through a coil L depending on the setting of the switches. A capacitor C is connected across the bridge through a switch S.sub.5 to receive the inductive energy stored in coil L on breaking the current flow path through the coil. The electrostatic energy stored in capacitor C can then be used to supply current through the coil in the reverse direction either immediately or after a time delay. Coil L may be a superconductive coil. Losses in the circuit can be made up by a trickle charge of capacitor C from a separate supply V.sub.2.