Abstract: 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 and then acquiring the NMR response signal thus excited, in the presence of a readout gradient oriented along the length of the cylindrical excitation beam and establishing position thereon. A Fourier transformation of the acquired data allows display of a real-time record of the profile of the sample along the axis of the cylindrical probe beam. The cylinder-beam axis can be oriented in an arbitrary direction by proper mixing of the excitation and readout gradient fields; use of three orthogonal gradients in a Cartesian coordinate system is presently preferred.

Abstract: An NMR antenna probe has at least one substantially circular surface coil arranged in a plane and a surface coil having substantially a Figure-8 shape, substantially coplanar with the at least one circular surface coil. The Figure-8 coil has a cross-over portion which is located substantially coaxial with the axis of the at least one circular surface coil. The coil corresponding to the least-NMR-sensitive nucleus is circular, while the non-circular coil corresponds to the most-NMR-sensitive nucleus. The circular coil is positioned on the side of the NMR probe closest to the subject to be studied.

Abstract: A single rotating NMR .pi. pulse provides simultaneous spatially-selective inversion or spin-echo refocussing of nuclear pins in two orthogonal dimensions. The two-dimensional spatially-selective pulse utilizes a single RF pulse, with either a square of an amplitude-modulated or a frequency-modulated envelope, and applied in the presence of an amplitude-modulated magnetic field gradient which reorients through the desired dimensions in which selection is desired while the RF pulse is present. These rotating, or ".rho.", pulses are useful for reduction of aliasing signal artifacts is restricted field-of-view high-resolution NMR imaging and, when combined with one-dimensional-localized chemical shift spectroscpoy techniques (such as those employing surface detection coils) is especially useful for the production of three-dimensionally localized NMR spectra.

Abstract: A method of suppressing at least one undesired resonance response signal while facilitating reception of at least one other desired NMR response signal from a coupled spin resonance in NMR spectroscopy, utilizes a pair of alternating sequences of RF signal pulses, with each sequence having an initial .pi./2 RF pulse, followed by a .pi. RF signal pulse having a temporal midpoint at a time interval T after the temporal midpoint of the initial pulse (where T=n/4J, with n being an odd integer and J being the spin coupling constant of the hydrogen nuclei) and a final .pi. RF signal pulse with a temporal midpoint at twice the time interval T after the temporal midpoint of the first .pi. RF signal pulse in that sequence. Only one of the pair of sequences is provided with a polarization transfer narrowband .pi. RF signal pulse symmetrically disposed about a temporal midpoint located at substantially a time interval T after the first .pi.

Abstract: A method for the complete inversion of magnetization by adiabatic fast passage during an NMR experiment on a sample having a selected nuclear specie with a Larmor frequency .omega..sub.0. A radio-frequency magnetic field is generated with an amplitude B.sub.1 and an instantaneous frequency .omega.(t) which is non-linearly swept, as a function of time, from a minimum frequency .omega..sub.1 substantially at a maximum offset frequency .DELTA..omega. below the Larmor frequency .omega..sub.0, through the Larmor frequency, to a maximum frequency .omega..sub.h substantially at the maximum offset frequency .DELTA..sub..omega. above the Larmor frequency. The non-linearly swept, monotonic RF signal is applied to the sample-being-investigated for a sweep time interval sufficient to invert the magnetization of the selected nuclear specie. The preferred sweep is a tangential function:.omega.(t)=.omega..sub.0 .+-..gamma.B.sub.1 tan (arcsin (.omega..sub.s t)), (A)or.omega.(t)=.omega..sub.0 .+-..gamma.B.sub.1 tan (.omega..