A substantially continuous image, recording motion of a portion of a sample, is provided by first NMR exciting, through use of a rotating-gradient (.rho.) pulse signal, a relatively narrow cylindrical region, typically with diameter less than 1 inch, of magnetization intersecting the sample to be imaged...http://www.google.es/patents/US4995394?utm_source=gb-gplus-sharePatente US4995394 - Fast NMR cardiac profile imaging
