Abstract: There is disclosed an NMR measurement method and NMR apparatus in which the temperature of the NMR detection coil or the RF irradiation coil hardly varies if pulsed RF power is applied to the coil during NMR measurements. The apparatus includes the detection coil or the RF irradiation coil, a first RF power application means for applying RF power of a frequency necessary for measurement of NMR signals, a second RF power application means for applying RF power of a frequency not affecting the measurement of NMR signals, and a control means for controlling the two power application means such that the sum of the RF power applied to the coil from the first application means and the RF power applied to the coil from the second application means is kept almost constant.

Abstract: A thermostatically controlled containment cell for a sample, suitable notably for a measuring device such as a nuclear magnetic resonance (NMR) spectrometer, NMR type measuring device including the cell, and method for implementation is disclosed. Cell (8) comprises a body of a tubular sleeve (9) made of a material so selected as not to interfere with NMR measurements, (for example a non-magnetic and non electrically conducting material) ending at its opposite ends with terminal parts (14, 16), containing a sample (S), and means (19–22) for circulating within tubular sleeve (9) a controlled-temperature heat carrier for maintaining the sample at a substantially constant temperature during measurements which liquid is selected to not disturb the NMR measurements. The cell containing the sample is first heated by circulation of the heat carrier. An overpressure sufficient to prevent boiling is established in the cell.

Abstract: The present invention provides for a cooling system for circulating a coolant to cool the patient bore. In one embodiment, that patient bore consists of two concentric cylinders separated by spacers running either longitudinally or helically. In another embodiment of the present invention, fluid may be passed either helically or longitudinally through tubes bonded to the outer diameter of the patient bore such that the parts of the bore that are exposed to the patient are directly cooled. In a third embodiment, the RF coil could form part of the patient bore, with the helical or longitudinal fluid channels surrounding the patient bore.

Abstract: A method (10) permits determining the temperature in a magnetic resonance check weighing system (24) of a sample in a container (22) on a production line at the time of magnetic resonance testing. Method (10) includes the steps of determining a time-temperature correction factor for the sample in the container (50), measuring the temperature of the composite sample and the container at a time other than the time of magnetic resonance testing (70), and applying the correction factor to the temperature of the composite sample and container at a time other than the time of magnetic resonance testing (80).

Abstract: A magnetic resonance imaging apparatus includes a calculator that calculates the quantity of heat generated (or to be generated) in a gradient magnetic field coil as a function of current supplied (or to be supplied) to the gradient magnetic field coil and at least one other factor such as eddy currents induced in a shield body used for shielding gradient field leakage flux from the imaged volume and/or delayed measurement of actual coil temperature. Such improved more timely temperature prediction and/or measurement is used to effect protective actions to better prevent permanent coil damage due to overheating.

Abstract: A nuclear magnetic resonance (NMR) probe is offered which can minimize positional shift of the detector portion caused by shrinkage of the support post due to cooling of the detector portion. The NMR probe has a vacuum-insulated container and the detector portion described above. The container has a cylindrical portion inserted in a magnet. The detector portion is made up of a detection coil and a tuning and matching circuit that are placed within the container. The detector portion is cooled by a cooling means such that NMR signals are detected with enhanced sensitivity. This probe is characterized in that the detector portion is mounted to the upper end surface or a side surface of the cylindrical portion.

Abstract: Briefly in accordance with one aspect, the present technique provides a method for heating a permanent magnet in a magnetic resonance imaging system. The method for heating a permanent magnet includes directly heating a surface of the permanent magnet using a surface heater. The present technique also provides a system for heating a permanent magnet in a magnetic resonance imaging system. The system includes a surface heater configured to directly heat a surface of the permanent magnet.

Abstract: An air feed device comprises a fluid motor to drive rotating vanes and blow air with high efficiency into a space accommodating a subject in a magnetic resonance device. The air feed device does not cause electrical interference with the magnetic imaging device.

Abstract: The temperature of permanent magnet blocks embedded in several positions in permanent magnets and base yokes will be adjusted by device of a heater to improve the static field uniformity.

Abstract: A method for decreasing entropy of a quantum system, for example nuclear spins. The quantum system comprising at least two subsystems, a first subsystem of elements with a first relaxation time (hereinafter—computation elements) and a second subsystem of elements with a second relaxation time (hereinafter—reset elements), the second relaxation time being shorter than the first relaxation time. The method comprises adiabatically decreasing the entropy of the computation elements in the system (by entropy compression, entropy transfer, or both) and increasing the entropy of at least some reset elements, so that the entropy of the subgroup of reset elements is overall increased; and waiting for the total entropy of the subgroup of reset elements to decrease, wherein the above two steps are carried out at least once.

Abstract: There is disclosed an NMR measurement method and NMR apparatus in which the temperature of the NMR detection coil or the RF irradiation coil hardly varies if pulsed RF power is applied to the coil during NMR measurements. The apparatus includes the detection coil or the RF irradiation coil, a first RF power application means for applying RF power of a frequency necessary for measurement of NMR signals, a second RF power application means for applying RF power of a frequency not affecting the measurement of NMR signals, and a control means for controlling the two power application means such that the sum of the RF power applied to the coil from the first application means and the RF power applied to the coil from the second application means is kept almost constant.

Abstract: A magnetic resonance imaging apparatus includes a unit (shim coil) that corrects uniformity of a magnetic field, a temperature detecting unit that detects a temperature of a magnet or its surroundings, and a control unit that controls the shim coil based on the detected temperature. The control unit calculates an error component for changing the uniformity of the magnetic field at the detected temperature of the magnet or its surroundings, based on a temperature characteristic of uniformity of the magnetic field calculated in advance. Further, the control unit calculates a shim current that generates a correction magnetic field for canceling the error component, and drives the shim coil based on this shim current.

Abstract: An RF coil construction for MRI is disclosed. The construction includes a device for cryogenically cooling receiver coils, at least two coil elements being cryogenically cooled by the device and forming an array. Each coil element includes at least two capacitors for tuning and matching the coil element. The construction also includes a circuit connected to each coil element for decoupling the coil element from the transmitter coil(s), and also for decoupling among coil elements.

Abstract: A thermal barrier is introduced to a magnetic resonance imaging system between the patient bore and each of the gradient coil assembly and RF body coil assembly to maintain the temperature within the patient bore below a maximum operating temperature. This allows the RF body coils to run cooler and also provides a thermal barrier between the gradient coils and the patient bore. In one preferred embodiment, a hollow conductor structure is introduced to the RF body coils at a position between the gradient coils and the patient bore tube. In another embodiment, the hollow conductor structure replaces the flat copper strip of the prior art and itself functions as the RF body coils.

Abstract: At least one quantity which is characteristic of the temperature-dependent magnetic properties of magnetizable material which interacts with the magnetic fields of a magnetic resonance imaging device is determined in order to compensate the temporally varying strength of the main magnetic field of a main magnet of such a device. On the basis of this quantity a compensation signal is formed for the correction of the influence of the varying field strength on the imaging result.

Abstract: A method of forming a magnetic resonance image involves separate measurement of the position of a measuring site. The magnetic resonance image is corrected on the basis of the measured position of the measuring site.

Abstract: An NMR experiment is carried out with a probe having an inlet tubing connected to a flow cell and a twisted-pair wire is tightly wrapped around the inlet tubing in a helical manner to serve as a heater. As a sample liquid flows from a sample source into the flow cell, it is preheated such that the time taken for it to reach thermal equilibrium is reduced. The use of a twisted-pair wire as a heater minimizes the effect of induced magnetic field. A control device includes a temperature sensor for sensing the temperature at the inlet tubing to control the electric current for the heater to maintain the preheating temperature at a selected level.

Abstract: A queue of samples for NMR analysis is disposed within a thermally isolate NMR magnet bore and distal elements of the queue approach thermal equilibrium concurrently with NMR analysis of a sample within the sensitive volume. In one embodiment, a sequence of NMR sample cells within a barrel coaxial with a vertical bore NMR spectrometer are maintained at a selected temperature by a heated gas and the queue of sample cells advances to the analytic position under gravity when the lowest sample cell is displaced from the queue in response to an end-of-analysis signal generated by said spectrometer.

Abstract: At least one quantity which is characteristic of the temperature-dependent magnetic properties of magnetizable material which interacts with the magnetic fields of a magnetic resonance imaging device is determined in order to compensate the temporally varying strength of the main magnetic field of a main magnet of such a device. On the basis of this quantity a compensation signal is formed for the correction of the influence of the varying field strength on the imaging result.

Abstract: A Magnetic Resonance Imaging (MRI) magnet field instability simulator (80) is provided. The simulator includes a rigid body motion generator (82) that simulates motion of one or more MRI system components. An eddy current analyzer (84) generates a magnetic stiffness and damping signal and an electromagnetic transfer function in response to the motions and a cryostat material properties signal. A mechanical model generator (86) generates a mechanical disturbance signal and a mechanical model of one or more MRI system components in response to the motions and the magnetic stiffness and damping signal. A structural analyzer (88) generates a motion signal in response to the mechanical model. A field instability calculator (90) generates a field instability signal in response to the electromagnetic transfer function and the motion signal. A method of performing the same is also provided.

Abstract: A method of tuning a high temperature superconductor (HTS) resonator includes the steps of providing a HTS inductor and a HTS capacitor, the HTS capacitor being electrically connected to the HTS inductor. A tuning body is provided adjacent to the HTS inductor and the HTS capacitor. The relative position of the tuning body with respect to the HTS inductor and the HTS capacitor is altered so as to tune the resonator. A tunable resonant circuit is provided that includes a substrate having a planar surface. At least one resonator formed from HTS material is disposed on the substrate, the resonator having one or more turns that when combined, turn through greater than 360°.

Abstract: A magnetic resonance imaging apparatus includes a calculator that calculates the quantity of heat generated (or to be generated) in a gradient magnetic field coil as a function of current supplied (or to be supplied) to the gradient magnetic field coil and at least one other factor such as eddy currents induced in a shield body used for shielding gradient field leakage flux from the imaged volume and/or delayed measurement of actual coil temperature. Such improved more timely temperature prediction and/or measurement is used to effect protective actions to better prevent permanent coil damage due to overheating.

Abstract: A magnetic resonance tomography apparatus, in particular an iron-guided or permanently magnetic, short or open magnetic resonance tomography apparatus, has thermally highly sensitive components and a temperature controller, formed by a foil heater which is provided with a control device and can be controlled in opposition to the internal dynamic heat sources.

Abstract: An apparatus is disclosed for generating a magnetic field of high field strength, spatial uniformity and minimal drift of magnetic field intensity over a temperature range of about 0° C. to 175° C. This apparatus may be used in a standard modular logging tool for direct downhole NMR measurements of various parameters of fluid samples of geologic formations near the walls of a borehole. In one embodiment, the apparatus is composed of two tubular permanent magnets made of different magnetic materials with different magnetic temperature coefficients to provide temperature compensation. The apparatus preferably also utilizes a pressure barrel that surrounds the magnets and provides a return path for magnetic flux lines, thereby increasing flux density within the measurement volume.

Abstract: A first room-temperature space is formed penetrating through a cryostat along a center axis of a split-type multi-layer cylindrical superconducting coil system which has a ratio of the maximum empirical magnetic field to the central magnetic filed of not larger than 1.3 and is horizontally arranged such that the center axis of the coil is in the horizontal direction, a room-temperature shim coil system is arranged in said first room-temperature space to improve the homogeneity of the magnetic field, a second room-temperature space is formed penetrating through the cryostat and passing through the center of said split gap in the vertical direction, and a sample to be measured and an NMR probe having a solenoid-type probe coil are inserted in said second room-temperature space. Further, the NMR analyzer has a new function constituted by a system for irradiating and detecting the electromagnetic waves having wavelengths of shorter than 0.1 mm.

Abstract: A Nuclear Magnetic Resonance (NMR) probe including a temperature controlled body for providing a sample for NMR measurement such that the temperature controlled body can adapt to the sample temperature to substantially maintain the body temperature. The body encases a conduit that can contain the sample for NMR measurement. In an embodiment, the desired temperature is the operating temperature of the NMR. The body is also in communications with a temperature sensor, a heat exchanger such as a heat exchanger, and a processor that includes instructions for controlling the body temperature.

Abstract: An RF coil construction for MRI is disclosed. The construction includes a device for cryogenically cooling receiver coils, at least two coil elements being cryogenically cooled by the device and forming an array. Each coil element includes at least two capacitors for tuning and matching the coil element. The construction also includes a circuit connected to each coil element for decoupling the coil element from the transmitter coil(s), and also for decoupling among coil elements.

Abstract: In a method for the operation of a magnetic resonance apparatus having a gradient coil system as well as a shim system with a number of shim plates with respectively allocated heaters, at least one information signal indicating a change in shape and/or position of the gradient coil system is determined or employed, the regulation of the heaters, and thus the temperatures of the respective shim plates ensuing dependent thereon.

Abstract: An MRI apparatus and method in which image data is produced using NMR signals obtained in plural measurements performed at different times respectively. Data is calculated indicating temperature distribution within the object for image data of each measurement time and spatial discontinuity of the calculated temperature distribution data is corrected. Temperature change distribution within the object between different measurement times is calculated by subtracting the corrected temperature distribution data of each measurement time, and the calculated temperature change distribution is transformed to indicative data for supply to a display for display.

Abstract: An amplifier and a coil are electrically connected to an amplifier in a coil system. A current controller is provided for adjustment of the current which is supplied from the amplifier to the coil. The current controller adjusts the current such that, at least on average, a predetermined power loss is converted to heat in the coil.

Abstract: An NMR resonator for receiving RF signals at desired resonance frequencies from a measuring sample in a volume under investigation disposed about a coordinate origin (x,y,z=0), with a means for producing a homogeneous magnetic field B0 in the direction of a z axis, wherein superconducting conductor structures are disposed between z=−|z1| and z=+|z2| on a surface which is translation-invariant (=z-invariant) in the z direction at a radial separation from the measuring sample, is characterized in that a compensation arrangement is additionally provided on the z-invariant surface, which extends to values of at least +|z2|+0.5|r|>z>−|z1|−0.

Abstract: At least one quantity which is characteristic of the temperature-dependent magnetic properties of magnetizable material which interacts with the magnetic fields of a magnetic resonance imaging device is determined in order to compensate the temporally varying strength of the main magnetic field of a main magnet of such a device. On the basis of this quantity a compensation signal is formed for the correction of the influence of the varying field strength on the imaging result.

Abstract: An apparatus is disclosed for generating a magnetic field of high field strength, spatial uniformity and minimal drift of magnetic field intensity over a temperature range of about 0° C. to 175° C. This apparatus may be used in a standard modular logging tool for direct downhole NMR measurements of various parameters of fluid samples of geologic formations near the walls of a borehole. In one embodiment, the apparatus is composed of two tubular permanent magnets made of different magnetic materials with different magnetic temperature coefficients to provide temperature compensation. The apparatus preferably also utilizes a pressure barrel that surrounds the magnets and provides a return path for magnetic flux lines, thereby increasing flux density within the measurement volume.

Abstract: Variations in spatial phase distribution due to static magnetic field changes are corrected based on phase variations at points, specifically, at three points or a plurality of points selected by ROI, in an area where no temperature change is encountered. And a temperature distribution image is determined by using a spatial phase distribution reflecting only temperature changes after the correction, thereby high-accuracy temperature distribution image information is provided.

Abstract: A gradient coil system for a magnetic resonance apparatus has at least one component of a cooling apparatus, and a latent heat storage apparatus which undergoes a phase transition during operation of the gradient coil system.

Abstract: Magnetic resonance temperature change monitoring of a heated portion of a tissue mass undergoing thermal treatment is more accurately accomplished by compensating for false temperature change measurements caused by movement of the mass and/or temporal changes of the magnetic field during the thermal MR Imaging, wherein the compensation is based on subtracting out “apparent temperature change” measurements of one or more unheated portions of the tissue mass located in a neighborhood of the heated portion, which form a temperature bias map of the tissue mass region.

Abstract: A controlling method for a nuclear magnetic resonance apparatus. The method includes: (A) cooling the high-temperature superconductor at a magnetization low temperature sufficiently lower than a superconductor transition temperature, and magnetizing the high-temperature superconductor with a magnetic field; (B) raising the temperature of the high-temperature superconductor at a magnetic flux setting temperature higher than the magnetization low temperature and lower than the superconductor transition temperature and setting a predetermined magnetic flux density; and (C) controlling the high-temperature superconductor in an operation temperature range lower than the magnetic flux setting temperature. Therefore, a strong static magnetic field comparable to a conventional superconducting magnet is formed without using a refrigerant (liquid helium) essential for operating the conventional superconducting magnet, and a magnetic flux density of the static magnetic field is held constant.

Abstract: A nuclear quadrupole resonance (NQR) method and probe for generating RF magnetic fields in different directions to distinguish NQR from acoustic ringing induced in a sample. Generally, an RF magnetic field is generated along an axis towards a sample to induce a resonance signal in the sample. The resonance signal includes NQR and acoustic ringing. The resonance signal is detected along the RF magnetic field axis. The acoustic ringing is detected along a direction orthogonal to the RF magnetic field axis. As a result, the NQR in the resonance signal can be distinguished from the acoustic ringing in the resonance signal.

Abstract: Systems and methods using magnetic resonance imaging for monitoring the temperature of a tissue mass being heated by energy converging in a focal zone that is generally elongate and symmetrical about a focal axis. A first plurality of images of the tissue mass are acquired in a first image plane aligned substantially perpendicular to the focal axis. A cross-section of the focal zone in the first image plane is then defined from the first plurality of images. A second plurality of images are acquired of the tissue mass in a second image plane aligned substantially parallel to the focal axis, the second image plane bisecting the first image plane at approximately a midpoint of the defined focal zone cross-section.

Abstract: A magnetic resonance apparatus has a basic field magnet for providing a uniform magnetic basic field, a gradient coil system for coding within the basic field as well as a passive shim system for homogenizing the magnetic basic field. This passive shim system is composed of shim iron plates that are placed in the magnetic basic field. A device is provided with which the temperature of these shim iron plates is controlled.

Abstract: Magnetic resonance temperature change monitoring of a heated portion of a tissue mass undergoing thermal treatment is more accurately accomplished by compensating for false temperature change measurements caused by movement of the mass and/or temporal changes of the magnetic field during the thermal MR Imaging, wherein the compensation is based on subtracting out “apparent temperature change” measurements of one or more unheated portions of the tissue mass located in a neighborhood of the heated portion, which form a temperature bias map of the tissue mass region.

Abstract: A nuclear magnetic resonance apparatus including: a cup-shaped high-temperature superconductor 20 having a hollow cylindrical shape or portion cooled to not more than a superconducting transition temperature in a vacuum insulating container 22; and a detection coil 12 for detecting an NMR signal of a material 11 to be measured inserted into the hollow cylindrical portion 20a of the high-temperature superconductor. The high-temperature superconductor is magnetized in an axial direction, a static magnetic field is thereby generated in the hollow cylindrical portion in a cylinder axial direction, and the NMR signal of a material is detected by the detection coil and the existing spectrometer. A strong static magnetic field comparable to a conventional superconducting magnet is formed without using a refrigerant (liquid helium) essential for operating the conventional superconducting magnet, and a strength distribution of the static magnetic field is homogeneous.

Abstract: Within upper and lower cryostats 17 and 18 for a super conducting magnet 2 level sensor 215 and 216 which measure respective amounts of liquid helium 212 therein are assembled and are connected to a measuring circuit 23. When a control signal of a computer 10 is provided to the measurement circuit 23 via the sequencer 9, the measurement circuit 23 performs automatic measurement of remaining amount of liquid helium 212 and the measured data is transferred to the computer 10. The computer 10 records the measured data as well as performs computation processing thereof and causes a display unit 12 to display the processing result as an effective management parameter of the liquid helium. Thereby, an open type MRI apparatus using a super conducting magnet with liquid helium monitoring system which is suitable for maintenance and management of liquid helium for the super conducting magnet can be provided.

Abstract: A burst wave 91 is applied as an RF magnetic filed in order to excite nuclei of hydrogen, and also a oradient magnetic field 95 along a readout direction is applied so as to excite magnetization in a stripe shape. Thereafter, while a magnetization-inverting RF magnetic field pulse 92 for selecting a slice is applied and a readout gradient magnetic field 96 is applied, a signal 97 is measured. At this time, a time instant when a spin echo is produced is made different from a time instant when a gradient magnetic field echo is produced, so that a phase rotation made by a chemical shift may be reflected on to a signal. The MR signal 97 is processed by a 2-dimensional Fourier-transform, and a phase distribution is calculated from both a real part and an imaginary part of complex data after the 2-dimensional Fourier-transform. Then, this calculated phase distribution is converted into a temperature change so as to display the temperature change.

Abstract: To correct static magnetic field intensity and homogeneity of an MRI system, B0 correction coil driving power sources respectively supply correction electric currents to B0 correction coils added to a pair of pillar yokes at the position where an imaging region is interposed therebetween, and the pair of B0 correction coils produce correction magnetic fields in which at least one of the direction and intensity is different, which are then applied to static magnetic fields produced by permanent magnets.

Abstract: A magnetic resonance tomography apparatus, in particular an iron-guided or permanently magnetic, short or open magnetic resonance tomography apparatus, has thermally highly sensitive components and a temperature controller, formed by a foil heater which is provided with a control device and can be controlled in opposition to the internal dynamic heat sources.

Abstract: An apparatus is disclosed for generating a magnetic field of high field strength, spatial uniformity and minimal drift of magnetic field intensity over a temperature range of about 0° C. to 175° C. This apparatus may be used in a standard modular logging tool for direct downhole NMR measurements of various parameters of fluid samples of geologic formations near the walls of a borehole. In one embodiment, the apparatus is composed of two tubular permanent magnets made of different magnetic materials with different magnetic temperature coefficients to provide temperature compensation. The apparatus preferably also utilizes a pressure barrel that surrounds the magnets and provides a return path for magnetic flux lines, thereby increasing flux density within the measurement volume.

Abstract: NMR images indicative of thermal changes in tissues undergoing therapy are produced using a gradient-recalled echo pulse sequence. Prior to therapy a contrast agent which shortens spin T1 relaxation time is injected into the patient and a reference phase image indicative of proton chemical shift is acquired. Temperature maps are produced in real-time as the therapy is subsequently performed by repeatedly acquiring NMR data, reconstructing measurement phase images and subtracting the reference phase image. The temporal rate at which the temperature maps are produced is increased by segmenting k-space and acquiring less than all the segments during each repetition.

Abstract: A magnetic resonance apparatus has a gradient coil system which has at least one flexible and thermally conductive damping structure that contains a flexible matrix and thermally conductive, particulate fillers. At least parts of a cooling device of the gradient coil system are arranged within the damping structure.

Abstract: There is disclosed a nuclear magnetic resonance apparatus comprising: a cup-shaped high-temperature superconductor 20 having a hollow cylindrical shape or portion cooled at a temperature not more than a superconducting transition temperature in a vacuum insulating container 22; and a detection coil 12 for detecting an NMR signal of a material 11 to be measured inserted into the hollow cylindrical portion 20a of the high-temperature superconductor. The high-temperature superconductor is magnetized in an axial direction, a static magnetic field is thereby generated in the hollow cylindrical portion in a cylinder axial direction, and the NMR signal of the material to be measured disposed in the magnetic field is detected by the detection coil and the existing spectrometer.