Abstract: An R.F. coil system is described for generating and/or receiving at least substantially homogeneous alternating magnetic fields, notably in nuclear magnetic resonance apparatus. The system is arranged about an essentially cylindrical examination space and comprises at least four conductor segments which are oriented essentially parallel to the longitudinal central axis of the examination space. The conductor segments are arranged about the circumference of the examination space symmetrically with respect to at least one plane which extends through the longitudinal central axis and are interconnected so as to form a closed loop. The conductor segments which receive a current of the same sense with respect to the longitudinal axis, are interconnected at neighboring ends by conductor elements which are oriented essentially in the circumferential direction of the examination space so as to form conductor groups.

Abstract: Measurement of magnetic field distributions is performed using a method based on the nuclear magnetic resonance (NMR) technique of Pourier imaging. By selecting objects which limit the spatial distribution of the NMR observable nuclei, images can be obtained which allow easy interpretation of the magnetic field distribution and facilitate rapid shimming of magnets. A method for providing a convenient display of field data is provided, as well as chemical shift imaging with correction for static field inhomogeneity. Results from these field plots are used as corrections for static field inhomogeniety when obtaining a chemical shift image. A method for localized spectral analysis from the chemical shift image is also provided.