Abstract: Magnetic resonance images are acquired by combining images obtained using two different spatial sensitivity profiles, 1?, 2?. The transverse magnetisation is caused to adopt such a profile 1? in one direction, resulting, in two dimensions, to a series of alternating stripes of respectively strong and weak, e.g. zero, transverse magnetisation. The regions of strong transverse magnetisation correspond to regions of high sensitivity in the acquired image. A complementary sensitivity profile 2? is stored as longitudinal magnetisation. A first image is then acquired in which the pixels are centered on the regions of high sensitivity within the first sensitivity profile 1?. The complementary sensitivity profile 2? is then recalled by inserting an additional gradient pulse and then a radio-frequency pulse into the pulse sequence and a second image acquired. As with the first image, the pixels are centered on the high-sensitivity regions, but these are mid-way between those within the first sensitivity profile 1?.

Abstract: Enhanced NMR images of a desired portion of an object are obtained by obtaining a plurality of NMR responses of the object each response comprising information from a plurality of smaller volumes within the object and by combining together the plurality of NMR responses by addition or subtraction to obtain enhanced images from the selected smaller volumes.

Abstract: A method of obtaining an NMR spectrum from a first region lying wholly within a second region of a sample material, comprises obtaining a signal indicative of a first NMR spectrum from substantially all of the second region of the sample material applying to the sample a magnetic field gradient, and simultaneously applying to the sample an Rf perturbing pulse having an amplitude and a frequency distribution such as to perturb nuclear spins in the said first region, but not outside it, removing the magnetic field gradient, and thereafter obtaining from the sample a signal indicative of a second NMR spectrum before relaxation of the perturbed spins in the said first region, and comparing the said first and second signals to obtain a difference spectrum attributable to the said region.Three separate perturbing pulses are preferably employed, each in the presence of a corresponding field gradient.