Abstract: A first NMR echo train is acquired with a single TE. A second NMR echo train is acquired with a first portion having the same TE and the second portion having a longer TE. When measurements are made with a low magnetic field gradient, processing the two echo trains can be used to determine gas in the formation.

Abstract: An NMR probe is provided that prevents homogeneity of the static magnetic field from being reduced in a sensitive area of an RF coil used for measuring an NMR signal. The RF coil is wound around a bobbin, and mounted on the NMR probe. In the NMR probe, a substance having a magnetic susceptibility of the same polarity as that of the RF coil is disposed on a surface of the bobbin which is not contacted by the RF coil. Alternatively, the bobbin is formed with grooves, and the RF coil is wound around the grooves. The bulk susceptibility of the bobbin or RF coil winding is adjusted such that the difference between the product of the depth of the groove and bulk susceptibility of the bobbin and the product of winding thickness and bulk susceptibility of the RF coil winding is 5 percent or less.

Abstract: Methods and apparatus for the characterization of formation fluids are disclosed. A downhole tool disposed in a borehole penetrating a subterranean formation obtains a NMR measurement, effects a change in a characteristic of the formation fluid, and obtains another NMR measurement subsequent to the change. Alternatively, the downhole tool effects a radial gradient of a characteristic of the formation and obtains NMR measurements at two or more selected radial distances from the wellbore wall. A parameter representative of the subterranean formation or the formation fluid is further determined from the NMR measurements.

Abstract: An embodiment of the invention relates to a portable or handheld device for performing NMR analysis. The device comprises a console and a strip which can be placed into the console through a slot or other means. The strip comprises a sample holding place and a microcoil for generating an excitation magnetic field across a sample in the sample holding space. A permanent magnet is provided either by the console or the strip and generates a static magnetic field which, together with the excitation magnetic field, creates NMR within the sample. Other embodiments of the invention also encompass method of performing NMR analysis using the portable device and method of making such devices.

Abstract: A magnetic resonance system is disclosed. The system includes a transceiver having a multichannel receiver and a multichannel transmitter, where each channel of the transmitter is configured for independent selection of frequency, phase, time, space, and magnitude, and each channel of the receiver is configured for independent selection of space, time, frequency, phase and gain. The system also includes a magnetic resonance coil having a plurality of current elements, with each element coupled in one to one relation with a channel of the receiver and a channel of the transmitter. The system further includes a processor coupled to the transceiver, such that the processor is configured to execute instructions to control a current in each element and to perform a non-linear algorithm to shim the coil.

Abstract: A method for performing magnetic resonance spectroscopy is described. The method generally includes applying a tailored multiband spectral-spatial radio frequency excitation pulse to a sample including a first species and at least a second species having a different resonant frequency than the first species. The multiband excitation pulse excites the first species according to a first amplitude and excites the second species according to a second amplitude that is substantially greater than the first amplitude. Data is acquired from the sample. The acquired data is then utilized to generate a spectroscopic output. By way of example, the spectroscopic output is a spectroscopic image. In particular embodiments, the data for the first and second species is acquired dynamically over an observation window of time.

Abstract: Techniques for magnetic resonance imaging (MRI) including obtaining a plurality of MRI images acquired at different echo times subsequent to an excitation pulse applied to a sample which is being imaged, performing a curve-fitting for a specified variation in each pixel of the MRI images, and using fitted parameters for the specified variation in the MRI images to synthesize the MRI images to form an image at any echo time with reduced noise. Performing singular value decomposition to determine the types of variation in each pixel of the MRI images and using only the most significant variations to synthesize the MRI images to form an image with reduced noise.

Abstract: A radio-frequency transmission system for a magnetic resonance system has a radio-frequency amplifier and a signal splitter with two inputs and two outputs. The signal splitter is fashioned so that the power of a radio-frequency signal provided at one of the two inputs is divided between the two outputs. A first input the two inputs of the signal splitter is thereby coupled with the output of the radio-frequency amplifier, and the two outputs of the signal splitter respectively serve for connection to different inputs of a transmission antenna of the magnetic resonance system in order to feed the output signals present at the two outputs of the signal splitter into the transmission antenna. The second input of the signal splitter is terminated with a terminating resistor arrangement with a variable reflection factor.

Abstract: The nuclear magnetic resonance machine comprises a device (101) for creating an intense main magnetic field B0 in a usable interior space (109) in the form of a tunnel with axis Z, a radio-frequency excitation device that also processes radio-frequency signals emitted in response by a body (150) placed in the usable interior space (109), and a set (110) of solenoidal gradient coils for superimposing on the intense magnetic field B0 components of a additional magnetic field, the gradient coils (111-122) being incorporated into tubes disposed in an annular cylindrical space (130).

Abstract: A magnetic resonance imaging system includes a primary magnet and a secondary magnet operable to produce magnetic fields within a sample being imaged. The MRI system further includes at least one RF coil that is operable to receive electromagnetic frequencies from the sample. The RF coil is formed from tubing that serves as a cooling conduit through which flows a cooling fluid provided by a cooling source. The cooling fluid cools the RF coils to improve imaging of the sample.

Abstract: An array coil including at least three conductive elements arranged at predetermined intervals, each of the conductive elements being in the form of a loop, and a plurality of switches that enable the conductive elements to be connected together according to a plurality of connecting patterns.

Abstract: A method of adjusting an excitation and detection circuit for nuclear magnetic resonance, the circuit comprising a probe (S) of the type comprising a single coil (L) for transmitting pulses to excite the nuclear spins of a sample immersed in a magnetic field and for detecting a resonance signal from said nuclear spins, said method being characterized by a step of tuning the resonant frequency in reception of said circuit to the Larmor frequency (f0) of the nuclear spins of the atoms that are to be detected. An excitation and detection circuit for nuclear magnetic resonance, said circuit being characterized in that it is adapted to implement an adjustment method as described above.

Abstract: An arrangement for receiving and/or transmitting RF signals and for feeding the same in a digital format between at least one RF antenna, coil and/or sensor unit (A, B) and a signal processing unit (8), by means of at least one digital cable (121, . . . 12n), especially for use in a magnetic resonance (MR) imaging system is disclosed, wherein at least one of the RF antenna, coil and/or sensor units (A, B) and at least one side of the digital cables (121, . . . 12n) is provided with a digital signal connector (10c, 11a; 121a, 121b, . . . 12na, 12nb) for separably connecting both by plugging the connectors together. By transmitting the RF signals in a digital format, especially in a digital optical format, a plurality of digital cables (121, . . . 12n) with different lengths and digital connectors (121a, 121b, . . .

Abstract: A magnetic resonance coil system 18 allows for the use of modular components and which in one embodiment is particularly well-suited for use with small animals and includes an animal receiving apparatus 202, a transmit coil module 204, and a receive coil module 206. The receive coil module 206 includes a cryogenic receive coil. The coil system 18 is selectively insertable in the bore of the gradient coil of a magnetic resonance examination system.

Abstract: A system and method for parallel imaging is disclosed that generates linear combination coefficient weights by solving systems of linear equations formulated with correlation values. An MRI apparatus includes a computer programmed to acquire MR data from an imaging volume for a plurality of encoding locations using an array of RF receiver coils. Correlation values are calculated from the MR data. From these calculated correlation values, synthesis weights are generated. An image is then reconstructed based on an application of the synthesis weights to at least a portion of the MR data acquired from the array of RF receiver coils.

Abstract: In a method and magnetic resonance (MR apparatus for reducing aliasing artifacts in the imaging for MR-monitored high intensity focused ultrasound HIFU therapy, a primary coil is used to receive the MR signals, and an additional coil is provided to receive interfering MR signals that form aliasing artifacts in the MR-monitored HIFU therapy imaging. The MR signals received by the primary coil and the interfering MR signals received by the additional coil are concurrently acquired. The interfering MR signals received by the additional coil are removed from the MR signals received by the primary coil. MR images are generated based on the MR signals with the interfering MR signals removed. Aliasing artifacts caused by the interfering MR signals thus are removed from the MR images without reducing the resolution of the scanned body parts in the MR images. In addition, the MR scanning time can be—maintained by using a proper phase oversampling technology in the concurrent signal acquisition.

Abstract: Apparatus and method for varying field strength in a magnetic resonance system while keeping a relatively uniform magnetic field distribution. In an embodiment, a two-pole, generally u-shaped magnet assembly generates a static and uniform magnetic field. The magnet assembly includes two facing magnet poles separated by an air gap. Holes may be formed with the magnet poles. The field control rods may be placed at a pre-determined distance into these holes and symmetrically or asymmetrically moved across each magnet poles in a controlled manner to change the magnetic field strength while keeping the uniform magnetic field distribution. Maximum magnetic field strength may occur when the rods are removed. Minimum magnetic field strength may occur when the rods are fully inserted.

Abstract: An automated image processing technique is disclosed that evaluates pixels of a phase-difference image to determine those pixels corresponding to inflowing phase data and background phase data. Phase-difference images are generated from a first acquisition and a second acquisition. Non-zero spatially varying background phase from the phase-difference images that are due to eddy currents induced by flow encoding gradients used to generate the phase-difference images is determined. This non-zero spatially varying background phase is removed from the phase-difference images to determine phase associated with flowing spins and phase associated with stationary spins.

Abstract: Many reservoirs of interest include heavy oil. In such reservoirs, partly at normal temperatures, many instruments commonly used for formation evaluation may not be able to distinguish between heavy oil and bound water in the formation. Passive or active heating is used to elevate the temperature of the fluids in the formation. At elevated temperatures, distinguishing between heavy oil and bound water is easier. Of particular interest is the increase in the resolvability of the transverse relaxation time T2 of NMR spin echo measurements. Additionally, the dielectric constant and the loss tangents of water and heavy oil show different temperature and frequency dependence.

Abstract: In NMR system, for preventing a temperature gradient which causes a decrease in S/N ratio from being created in a sample area while suppressing deterioration in homogeneity of a magnetic field, a thermal conductor having high thermal conductivity is disposed in a room-temperature shim coil. The thermal conductor is provided as a coil bobbin, the temperature of the thermal conductor being controlled by a temperature controller using a heat exchanger. Temperature control gas, which is adjusted to a temperature equal to that of the room-temperature shim coil, is fed from the downside of a sample tube, and it is possible to suppress a temperature gradient from being created in a sample area. According to the present invention, since the temperature distribution can be made to be uniform so as to avoid creating a temperature gradient in the sample area while suppressing deterioration of homogeneity in the magnetic field, the NMR spectrum is sharpened so as to improve the S/N ratio.