Abstract: A method is provided for measuring the distribution of the extent of molear transport along two orthogonal directions, and further for measuring the anisotropy of molecular transport. For a sample which consists of compartments which contain mobile spins, such as round or cylindrical micelles, the distribution of compartment eccentricities can be calculated from this measurement. This method enables the anisotropy of molecular transport to be determined for a sample independently of any bulk orientation within the sample and thus the anisotropy of local geometries can be determined.

Abstract: An improved method and apparatus for nuclear magnetic resonance (NMR) imaging are provided by intercalating a magnetic field gradient in the form of short pulses into an NMR line-narrowing sequence. By inserting the short pulses into predetermined windows in the line-narrowing pulse sequence, the resolution of NMR images obtained thereby is increased and image artifacts from homogenous contributions to the natural linewidth are reduced. Furthermore, the short gradient pulses may be intercalated into known multiple pulse sequences or new multiple pulse sequences for specific imaging purposes which allows far more freedom in designing efficient and improved pulse cycles for NMR imaging.

Abstract: A system and method for detecting a class of explosives and narcotics containing nitrogen in a specimen by nuclear quadrupole resonance which improves the selectivity, sensitivity and spatial localization over conventional detection systems. As a result, sub-kilogram quantities of explosives and narcotics against a background of more benign materials may be detected by the nuclear quadrupole resonance system and method. Also, by the use of a meanderline surface coil, the electrical and magnetic fields will fall off rapidly over a short distance so that a localized region may be scanned and people may be scanned without depositing substantial RF power into the body. Furthermore, by using a strong off-resonance comb (SORC) irradiation sequence, the signal-to-noise ratio of the detected signal is improved for obtaining a more accurate detection signal from the specimen.

Abstract: Materials are imaged by exciting only one volume of interest (VOI) at a t while leaving the other undisturbed. By switching the irradiation frequency and probe tuning to the next VOI, the time delay between acquisitions of different VOI's may be essentially eliminated. The present invention may be implemented using a new coil design which is also useful for microscale planar imaging.

Abstract: A method for obtaining a nuclear magnetic resonance image of a sample is performed by first placing the sample in a homogeneous static magnetic field excited with a homogeneous transmitter device. Spin magnetization in the sample is thus initially detected with an inhomogeneous receiver device such that an induced voltage in the receiver device depends on a spatial location of precessing nuclei in the sample. Then, a spatial coupling of the sample and the receiver device is varied and the spin magnetization in the sample is again detected with the inhomogeneous receiver device. The full spatial distribution of the spin density of the sample and hence an image of the sample is then determined with the spin magnetizations detected. Either the sample is moved relative to the receiver device, or the spatial coupling of the receiver device and the sample is electronically altered. Any spin interactions are eliminated by using coherent averaging techniques before the detecting steps.