Abstract: A borehole logging tool comprises a Nuclear Magnetic Resonance (NMR) tool and is pulsed according to a selected Carr Purcell-Meiboom Gill (CPMG) sequence. Because the recovery time between CPMG sequences is short, the sequence acts as a filter such that signals induced by rapidly relaxing nuclei of fluid bound in an earth formation are detected. In this manner, the NMR tool gives a direct indication bound fluid volume and fast logging speeds are achieved.

Abstract: Pulsed NMR system for industrial measurements comprising sample throughput system (P, LI, V1, V2) and user system controls (104) to establish digitized free induction decay (FID) curves (C), from which fast Gaussian, slower modified Gaussian or preferably slower Gaussian, and exponential components are determined using a Marquardt-Levenberg iteration technique, and using regression techniques to correlate the FID curve components to the physical quantities of the target nuclei.

Abstract: Apparatus for tuning a system for detecting a target substance through the use of nuclear quadrupole resonance (NQR) or nuclear magnetic resonance (NMR). The apparatus tunes an RF coil which is employed to excite the substance under test. The tuning apparatus includes a series of fixed value capacitors switched in the tuning circuit by controllable switches. A programmable controller is employed to control the switching and thereby the tuning of the coil.

Abstract: Magnetic resonance is excited (50) in first and second species dipoles of a subject in a temporally constant magnetic field. The resonance is refocused (52) to generate a spin echo (54) centered at a time when the first and second species resonance signals are in-phase. Gradients echoes (64, 68) are generated, centered at a time (2n+1).pi./.delta..omega. before and after the spin echo, where .delta..omega. is a difference between the first and second species resonance frequencies. In this manner, the first and second species signals are 180.degree. out-of-phase in the gradient echoes. The resonance is refocused (82) one or more times to generate additional spin and gradient echoes with different phase encodings (78). The sequence is repeated with yet more phase encodings, and magnetic resonance signals from the spin echo and the two gradient echoes are reconstructed (86) into a spin echo image (s.sub.0) and a pair of gradient echo images (s.sub.+1, s.sub.-1).

Abstract: A magnetic resonance apparatus is provided to analyze, diagnose, or treat matter. In general, the MRA is used to transmit a synthesized resonance pattern into the subject matter under test which encounters the inherent resonance pattern produced by the tested subject matter. This information is returned to the MRA, which, after removing the static capacity and resistance, is analyzed, digitized and compared to a coded predetermined resonance pattern and examined for irregularities. The presence or lack of irregularities can be used to analyze and diagnose matter. A second set of test pattern signals can also be applied to alter the substance's natural magnetic resonance, thereby treating the substance to achieve a particular resonance pattern.

Abstract: A probe for an MRI apparatus in a vertical magnetic field system including: an array coil which is formed by arranging a plurality of unit coils, which can be driven independently of one another, in a direction perpendicularly intersecting a direction of a static magnetic field; and a compensating coil which forms a magnetic field in a direction perpendicularly intersecting both a direction of a magnetic field formed by the array coil and the direction of the magnetic field, a signal detected by the array coil and a signal detected by the compensating coil being composed so as to be in phase with each other, thereby to be outputted.

Abstract: A method of reducing bias error in nuclear magneic resonance (NMR) spin-echo signals. The method includes filtering the signals using a filter having a bandwidth inversely related to the length of time from the initiation of the measurement of the NMR signals. In a preferred embodiment, the NMR spin-echo signal measurements are filtered using a moving average filter having an averaging span which increases with respect to the time elapsed from initiation of the spin-echo measurement sequence.

Abstract: An apparatus for measuring physical properties of micro area which has an object to measure physical properties from a micro area on an atomic scale on the surface of a test sample such as electron spin, nuclear magnetic moment, and nuclear quadrupole moment in high sensitivity, allows the probe 2 of the atomic force microscope to approach the surface of the test sample 1, applies a magnetic field to the test sample 1 by the magnetic field generation coil 27 and the magnetic paths 22 to 26 and furthermore a high frequency electromagnetic field to the test sample 1 by the coils 16 and 17 respectively, and detects a signal from atoms existing on the surface of the test sample 1 which are resonant with the high frequency electromagnetic field by the probe 2.

Abstract: A method of NQR testing a sample having at least one NQR property which varies with a given environmental parameter comprises applying excitation to the sample to excite NQR resonance and detecting the NQR response signal. The excitation is such as to excite an NQR response signal which is detectable during the detection step over a predetermined range of the environmental parameter. The invention also relates to a method of, and apparatus for, NQR testing for the presence of selected nuclei (particularly nuclei of integral spin quantum number, such as .sup.14 N) in a sample. It also relates to a method of determining the spatial distribution of temperature within a sample.

Abstract: In a GRASE magnetic resonance method, most profiles in k-space with a certain k.sub.y value are measured with different magnetic field read gradient polarity and at different time intervals from the excitation RF-pulse. The two resulting sets of measurements, with positive and negative read gradient polarity, respectively, are used to correct read gradient polarity dependent phase errors, in order to obtain reconstructed images in which the effects of these phase errors are greatly reduced. In an improved version the measurements are used to reconstruct images with a predictable T.sub.2 weighting.

Abstract: Each pole plate of a pole plate magnet of a magnetic resonance imaging apparatus has a sub-coil of the gradient coil allocated to it. Each sub-coil is composed of a primary and a secondary coil, respectively lying on one of two overlapping surfaces of a frustrum. The winding curve of each sub-coil changes multiply over a surface of the frustrum between the surfaces. The gradient coil can thus be optimized such that the required, maximum current densities become significantly lower compared to conventional, actively shielded arrangements.

Abstract: Hybrid imaging (HI) sequences used for magnetic resonance (MR) imaging and inherently degraded by T2 effects and additive measurement noise are enhanced. Wiener filter and linear prediction (LP) technique is used to process HI MR signals in the spatial frequency domain (K-space) and the hybrid domain respectively. Based on the average amplitude symmetry constraint of the spin echo signal, the amplitude frequency response function of the T2 distortion is estimated and used in the Weiner filter for a global T2 amplitude restoration. Then a linear prediction technique is utilized to obtain local signal amplitude and phase estimates around discontinuities of the frequency response function of the equivalent T2 distortion filter. These estimates are used to make local amplitude and phase corrections. The effectiveness of this combined technique in correction T2 distortion and reducing the measurement noise is analyzed and demonstrated using experiments on both phantoms and humans.

Abstract: Using 3-D spectral-spatial excitation, the center frequency of the spectral passband can be varied as a function of two spatial coordinates. Such variation could be tailored to field map data to compensate for B.sub.0 shifts. The 3-D excitation has 3-D spiral trajectories in k-space.

Abstract: A multi-planar imaging method employs magnetic resonance to detect image data from multiple planes within a subject. Data from each plane are detected in response to the same readout gradient and are simultaneously detected. The image planes can be arbitrarily oriented with respect to each other and with respect to the readout and phase-encoding image formation magnetic field gradient pulses if desired. Overlap of image data from each of the excited image planes in the acquired image is prevented by employing a thick refocusing slab oriented orthogonal to the readout and phase-encoding directions, or by choosing planes which intersect outside the subject's anatomy.

Abstract: An RF coil for NMR experiments having a conductive path for flowing a field-cancelling current to isolate magnetically the RF coil from its environment. NMR data, particularly MRI data from a human subject, is collected with the receiver coil magnetically shielded to avoid loss of the received signal energy to the environment.

Abstract: In a diagnostic magnetic resonance apparatus having an examination space, a radio-frequency antenna and a gradient coil system, the radio-frequency antenna is arranged closer to the examination space than is the gradient coil system. A radio-frequency shield arranged between the radio-frequency antenna and the gradient coil system, and has a first electrically conductive layer arrangement and a second electrically conductive layer arrangement arranged lying opposite the first arrangement, these being separated from one another by a dielectric. The layer arrangements have interconnects arranged side-by-side that are separated from one another by electrically insulating slots. The slots of the first layer arrangement are arranged offset relative to the slots in the second layer arrangement.

Abstract: In a double resonance antenna arrangement for a nuclear magnetic resonance apparatus having at least one conductor section that defines an examination region, a series circuit of a capacitive element and an inductive element is connected in parallel with at least a part of the conductor section.

Abstract: In a method and apparatus for the production of a nuclear magnetic resonance (NMR) tomography image with radio frequency (RF) signals from an extended measuring object (11) being detected by n surface coils (2a, 2b, 2c, 2d) of an NMR apparatus, whereby n>1, and the n RF signals are separately preamplified by n preamplifiers (3a, 3b, 3c, 3d) each assigned to one of the n surface coils (2a, 2b, 2c, 2d), and subsequently further amplified and detected in a phase sensitive fashion, as a result of which a low frequency signal is obtained in each case which is introduced to one of n low pass filters (5a, 5b, 5c, 5d) of an analog/digital converter (ADC) and whereby n partial images are produced in a computer (8) from the n signals obtained in this fashion and assembled into a single NMR tomography image of the measuring object (11) in a region of interest, the signals emanating from the n low pass filters (5a, 5b, 5c, 5d) are introduced to a single ADC (7) via a first multiplexing circuit (6) to be digitized and

Abstract: A RF shield for an MRI system with a cylindrical geometry is disclosed. The RF shield is a plurality of panels with polyester on one side and copper cladding on the other side. The shingles include an adhesive so the shingles can be overlapped onto each other such that half of each shingle adheres to an adjacent shingle and the other half of the shingle adheres to the inside surface of the gradient coil assembly.

Abstract: Current supply for MRI magnet having an output impedance which has been tailored to have the desired shape by using voltage and current feedback. The impedance is small at frequencies which are large with respect to the magnet L/R and the impedance is large at very low frequencies.