The invention provides an investigation of chemical shift for an element, for example phosphorus, in a region of a body, in one example resonance is preferentially in a line in a slice of the body. Frequency dispersion down the line is produced by a pulsed field having a switched gradient so that the...http://www.google.com.au/patents/US4361807?utm_source=gb-gplus-sharePatent US4361807 - Nuclear magnetic resonance systems
