1602 results about "Resonance signal" patented technology

A method for the detection of analytes using resonant mass sensors or sensor arrays comprises frequency encoding each sensor element, acquiring a time-domain resonance signal from the sensor or sensor array as it is exposed to analyte, detecting change in the frequency or resonant properties of each sensor element using a Fourier transform or other spectral analysis method, and classifying, identifying, and / or quantifying analyte using an appropriate data analysis procedure. Frequency encoded sensors or sensor arrays comprise sensor elements with frequency domain resonance signals that can be uniquely identified under a defined range of operating conditions. Frequency encoding can be realized either by fabricating individual sensor elements with unique resonant frequencies or by tuning or modifying identical resonant devices to unique frequencies by adding or removing mass from individual sensor elements. The array of sensor elements comprises multiple resonant structures that may have identical or unique sensing layers. The sensing layers influence the sensor elements' response to analyte. Time-domain signal is acquired, typically in a single data acquisition channel, and typically using either (1) a pulsed excitation followed by acquisition of the free oscillatory decay of the entire array or (2) a rapid scan acquisition of signal from the entire array in a direct or heterodyne configuration. Spectrum analysis of the time domain data is typically accomplished with Fourier transform analysis. The methods and sensor arrays of the invention enable rapid and sensitive analyte detection, classification and / or identification of complex mixtures and unknown compounds, and quantification of known analytes, using sensor element design and signal detection hardware that are robust, simple and low cost.

A system and method for using magnetic resonance imaging to increase the accuracy of electrophysiologic procedures is disclosed. The system in its preferred embodiment provides an invasive combined electrophysiology and imaging antenna catheter which includes an RF antenna for receiving magnetic resonance signals and diagnostic electrodes for receiving electrical potentials. The combined electrophysiology and imaging antenna catheter is used in combination with a magnetic resonance imaging scanner to guide and provide visualization during electrophysiologic diagnostic or therapeutic procedures. The invention is particularly applicable to catheter ablation, e.g., ablation of atrial fibrillation. In embodiments which are useful for catheter ablation, the combined electrophysiology and imaging antenna catheter may further include an ablation tip, and such embodiment may be used as an intracardiac device to both deliver energy to selected areas of tissue and visualize the resulting ablation lesions, thereby greatly simplifying production of continuous linear lesions. The invention further includes embodiments useful for guiding electrophysiologic diagnostic and therapeutic procedures other than ablation. Imaging of ablation lesions may be further enhanced by use of MR contrast agents. The antenna utilized in the combined electrophysiology and imaging catheter for receiving MR signals is preferably of the coaxial or “loopless” type. High-resolution images from the antenna may be combined with low-resolution images from surface coils of the MR scanner to produce a composite image. The invention further provides a system for eliminating the pickup of RF energy in which intracardiac wires are detuned by filtering so that they become very inefficient antennas. An RF filtering system is provided for suppressing the MR imaging signal while not attenuating the RF ablative current. Steering means may be provided for steering the invasive catheter under MR guidance. Other ablative methods can be used such as laser, ultrasound, and low temperatures.

The present invention relates to methods, software and systems for monitoring fluctuations in magnetic resonance signals. These methods may be used for measurements of the human brain and nervous system, and may be used for measuring electric currents and electromagnetic fields internal to an object. This method may include the use of a reference signal to accomplish differential recording of electromagnetic fields from two or more spatial locations.

The present invention relates to methods, software and systems for monitoring fluctuations in magnetic resonance signals. These methods may be used for measurements of the human brain and nervous system, and may be used for measuring electric currents and electromagnetic fields internal to an object. This method may include the use of a reference signal to accomplish differential recording of electromagnetic fields from two or more spatial locations.

A method of imaging using magnetic resonance includes administering hyperpolarized noble gas to a subject in a region to be imaged, applying a magnetic field of a magnitude between about 0.0001 Tesla and about 0.1 Tesla to the subject at least in the region of the subject to be imaged, detecting a spatial distribution of magnetic resonance signals of the hyperpolarized noble gas in the subject, and producing a representation of the spatial distribution.

Combined positron emission tomography and magnetic resonance tomography unit for imaging an examination object in an examination space, comprising a positron emission tomography unit that has a unit part assigned to the examination space, and a first evaluation unit for evaluating the electric signals for a positron emission tomography image of the examination object. The unit part in this case comprises a gamma ray detector with an assigned electronics unit. Furthermore, the combined unit comprises a magnetic resonance tomography unit and a second evaluation unit for evaluating the magnetic resonance signals for a magnetic resonance image of the examination object. The magnetic resonance unit in this case has a high frequency antenna device as well as a gradient coil system, the high frequency antenna device being arranged nearer to the examination space than the gradient coil system, as well as a high frequency shield arranged between the gradient coil system and the high frequency antenna device. The positron emission tomography unit part is arranged in this case between the high frequency shield and the high frequency antenna device, and is provided, at least on the side facing the high frequency antenna device, with a shielding cover that is caused by the high frequency antenna device and is opaque to high frequency radiation.

The present invention discloses a diffusion edited pulse technique that allows information about a fluid to be extracted, comprising: a) obtaining a fluid sample; b) generating a sequence of magnetic field pulses in the fluid, the sequence comprising an initial magnetic field pulse, a first portion that follows the initial magnetic field pulse, and a second portion that follows the first portion; c) detecting magnetic resonance signals using the second portion of the sequence; d) modifying the first portion of the sequence, and repeating steps (b) and (c); and e) extracting information about the fluid by determining relaxation and diffusion characteristics and their correlation based on the signals detected in steps (c) and (d). Also disclosed is a logging tool equipped with a processor to implement the diffusion edited pulse technique.

A method of magnetic resonance imaging of an object comprises the steps of arranging the object in a stationary magnetic field, subjecting the object to an excitation and encoding sequence of magnetic field gradients resulting in k-space sampling in two segments along the phase encoding direction, wherein the encoding sequence of the magnetic field gradients is selected such that the two segments in k-space are sampled along trajectories beginning with a central k-space line through the k-space center and continuing to opposite k-space borders of the two segments, collecting magnetic resonance signals created in the object, and reconstructing an image of the object based on the magnetic resonance signals, wherein one central k-space line is sampled in both of the two k-space segments, and intersegment phase and / or intensity deviations are corrected in both k-space segments using the magnetic resonance signals collected along the central k-space line. Furthermore, an imaging device for magnetic resonance imaging of an object is described.

The reversible transverse susceptibility of magnetic nanoparticles is used to achieve magnetic flux amplification in magnetic resonance settings. Nanoparticles having substantially uniaxial or unidirectional magnetic anisotropy and a reversible transverse susceptibility in the presence of the high DC magnetic field provide either or both of an amplification of the generated signal of an inductive coil or the detected signal of an inductive coil.

A magnetic resonance imaging apparatus includes a unit which generates a diffusion weighted image based on a magnetic resonance signal from an object, a unit which calculates an apparent diffusion coefficient based on the diffusion weighted image, and a processing unit which subjects the diffusion weighted image to a process of indicating a region having the apparent diffusion coefficient of less than a threshold value with a highlight in contrast with other region.

Diffusion tensor magnetic resonance signals are analyzed. Diffusion weighted, signals are acquired, each signal having a plurality of voxels (10). The diffusion weighted signals are sampled to obtain at least one set of resampled diffusion weighted signals (11). A diffusion tensor for each voxel is determined from each set of the resampled diffusion weighted signals (12). An empirical statistical distribution is determined for a quantity associated with the diffusion tensor from the diffusion tensors determined from the at least one set of the resampled diffusion weighted signals (13).

In a method for implementation of a magnetic resonance examination, and a magnetic resonance apparatus, and an array for acquisition of magnetic resonance signals, and a magnetic resonance signal at a magnetic resonance frequency are acquired from an examination region with an array of frequency conversion units after an RF excitation and are radiated as frequency-converted signals. The resulting signal field is acquired by a number of reception antennas of a second antenna array, which are arranged at different spatial positions and thus allow a spatial resolution of the frequency-converted signals. The acquired acquisition signals are used for image reconstruction.

A noninvasive image measuring method of measuring internal organ / tissue temperature using an MRI system. Temperature measurement insusceptible to body motion and spatial variation of magnetic field is realized by utilizing the position and size of a temperature change region as a priori information to determine the phase distribution of the complex magnetic resonance signal of water proton at a given temperature point and by subtracting the phase distribution before the temperature change estimated (self-referred) from the phase distribution in the peripheral region for each pixel of the image, thereby eliminating the subtraction process of image before and after temperature change. The precision of temperature measurement can be enhanced by estimating a complex curved surface formed of the peripheral region in each temperature change region of the real-part and imaginary-part images of the complex magnetic resonance signal, and calculating the phase difference between an actually measured complex signal distribution and the estimated complex signal distribution of the complex signal distribution for each pixel, thereby reducing the estimation error due to phase transition from −π to +π occurring in a phase distribution. Furthermore, temperature can be measured through optimal imaging following up body motion by using an optical positioning system in combination even if the part being measured is shifted.

A noninvasive image measuring method of measuring internal organ / tissue temperature using an MRI system. Temperature measurement insusceptible to body motion and spatial variation of magnetic field is realized by utilizing the position and size of a temperature change region as a priori information to determine the phase distribution of the complex magnetic resonance signal of water proton at a given temperature point and by subtracting the phase distribution before the temperature change estimated (self-referred) from the phase distribution in the peripheral region for each pixel of the image, thereby eliminating the subtraction process of image before and after temperature change. The precision of temperature measurement can be enhanced by estimating a complex curved surface formed of the peripheral region in each temperature change region of the real-part and imaginary-part images of the complex magnetic resonance signal, and calculating the phase difference between an actually measured complex signal distribution and the estimated complex signal distribution of the complex signal distribution for each pixel, thereby reducing the estimation error due to phase transition from −π to +π occurring in a phase distribution. Furthermore, temperature can be measured through optimal imaging following up body motion by using an optical positioning system in combination even if the part being measured is shifted.

Provided is an over-voltage protection device for a resonant wireless power reception device. The over-voltage protection device includes a resonance signal receiver for receiving a wireless resonance signal transmitted from a wireless power transmission device, an over-voltage protector which is driven by a driver in an over-voltage protection operation to detune a resonance frequency of the reception device, thereby reducing reception power, the driver for driving the over-voltage protector according to a control signal in the over-voltage protection operation, and a controller for outputting the control signal for driving the over-voltage protector to the driver when it is determined that over-voltage occurs.

The invention discloses an electromagnetic resonance-based nondestructive testing method for metal materials. According to the method, responding resonance signals of eddy current testing are obtained through multipled resonant capacitors in testing coils, comparative analysis of the responding resonance signals is carried out, and the relationships between a defect size and a signal amplitude and between defect depth and a signal phase are calibrated in advance, thereby enabling convenient nondestructive testing of metal materials. The electromagnetic resonance-based nondestructive testing method not only can produce same defect detection effects as a plurality of conventional electromagnetic testing methods like single-frequency eddy current and pulsed eddy current do, but also can effectively detect internal defects in a workpiece and detect workpieces with complicated surface conditions such as a casting surface, an unsmooth surface, a surface with oil stains, a rust-resisting paint, a corrosion layer or other pollutants, etc., without contact under the condition of a high liftoff value; according to the method, no cleaning is needed for test pieces, and particularly, no cumbersome processes like magnetization and demagnetization of magnetic metal materials are needed.

The present invention provides a magnetic resonance imaging apparatus and a magnetic resonance imaging method which improve the imaging efficiency. A preview scan initiator unit is provided for initiating a preview scan for scanning the slice position set prior to performing the actual imaging scan. Based on the magnetic resonance signals from the subject obtained by the review scan initiated by the preview scan initiator unit, the preview image for the slice position set by the slice position setting unit is generated to display on the display screen by the display unit.

An apparatus including a probe unit and a control / imaging unit, the probe unit including a converter converting a sampled magnetic-resonance signal into a digital signal, a first transmitter converting the digital signal into a first-radio signal, a first receiver receiving a second-radio signal, and performing detection on the second-radio signal to obtain a first-received signal, and a clock-regeneration unit regenerating a clock component from the first-received signal to generate a regenerated-clock signal, the control / imaging unit including a second-receiver receiving the first-radio signal to obtain a second-received signal, a data processor performing data processing on the second-received signal in synchronism with a reference-clock signal to obtain a video signal, and a second transmitter including a modulator modulating a carrier wave using the reference-clock signal, the second transmitter converting the reference-clock signal into the second-radio signal and transmitting the second-radio signal through the second-wireless channel.

An examination platform for a magnetic resonance apparatus has a patient bed for supporting a patient, a local antenna device for acquisition of magnetic resonance signals, and a drive device arranged at the patient bed. The drive device is coupled with the local antenna device. The local antenna device thus can be moved parallel to the longitudinal axis of the patient bed independently of a movement of the patient bed. A magnetic resonance apparatus and a method for acquisition of image data of a patient employ such an examination platform.

A magnetic resonance imaging apparatus includes a movement unit which moves a subject placed in a static magnetic field, a collector which collects data corresponding to a magnetic resonance signal emitted from the subject, a detector which detects a position of a particular section of the subject in the static magnetic field, a reconstruction unit which reconstructs an image, based on the collected data, when the detected position falls within an allowable area, and a controller which controls the movement unit to compensate for a deviation of the detected position from a reference position.

A system and method are provided to detect target analytes based on magnetic resonance measurements. Magnetic structures produce distinct magnetic field regions having a size comparable to the analyte. When the analyte is bound in those regions, magnetic resonance signals from the sample are changed, leading to detection of the analyte.

The invention discloses a magnetic luminescent composite nano-particle Fe3O4 / CdTe / SiO2 and a preparation method thereof. The method for preparing the magnetic luminescent composite nano-particle Fe3O4 / CdTe / SiO2 comprises the steps of: firstly preparing hydrophobic monodisperse Fe3O4 nano-particles by adopting a chemical oil-phase high-temperature method, and modifying the surfaces of the hydrophobic Fe3O4 nano-particles to ensure that the hydrophobic Fe3O4 nano-particles are dispersed in a water phase; preparing luminescent CdTe quantum dots of which the surfaces are provided with carboxyl groups, and precipitating the luminescent CdTe quantum dots on the surfaces of the magnetic Fe3O4 nano-particles through the co-precipitation; then utilizing ligand exchange to modify a silane coupling agent on the surfaces of the luminescent CdTe quantum dots; and finally forming an outermost SiO2 coating layer through silane or silicon ester hydrolysis. The diameter of the magnetic luminescent composite nano-particle Fe3O4 / CdTe / SiO2 is between 30 and 50nm; the magnetic luminescent composite nano-particle Fe3O4 / CdTe / SiO2has double functions of magnetism and fluorescence at the same time, has strong and durable fluorescence intensity after labeling rat bone marrow-derived mesenchymal stem cells, and apparently reduces cellular magnetic resonance signals. The particle has broad application prospect in the fields such as biological labeling, bioseparation and the like.

An assembly for shielding an implanted medical device from the effects of high-frequency radiation and for emitting magnetic resonance signals during magnetic resonance imaging. The assembly includes an implanted medical device and a magnetic shield comprised of nanomagnetic material disposed between the medical device and the high-frequency radiation. In one embodiment, the magnetic resonance signals are detected by a receiver, which is thus able to locate the implanted medical device within a biological organism.

An assembly for shielding an implanted medical device from the effects of high-frequency radiation and for emitting magnetic resonance signals during magnetic resonance imaging. The assembly includes an implanted medical device and a magnetic shield comprised of nanomagnetic material disposed between the medical device and the high-frequency radiation. In one embodiment, the magnetic resonance signals are detected by a receiver, which is thus able to locate the implanted medical device within a biological organism.

A receiver for a resonance signal of a magnetic resonance imaging system generates a baseband signal for image processing by dividing a raw resonance signal among multiple parallel channels, each amplified at a respective gain. A digital channel selector determines, at any given moment, a lowest-distortion channel to be further processed. Amplitude and phase error compensation are handled digitally using complex multipliers, which are derived by a calibration, based on a simple Larmor oscillator, which can be done without the need for a sample and without repeating when measurement conditions are changed. One of the important benefits of the invention is that it provides for gain selection without repeated calibration steps. This is particularly important in systems that employ fast imaging techniques such as fast spin echo, where the invention can speed imaging substantially.

A magnetic resonance imaging apparatus acquires magnetic resonance signals by the PI method using an RF coil unit having basic coils serving as surface coils which are arrayed with at least two coils along a static magnetic field direction (z direction) and at least two coils along each of two orthogonal x, y directions. The coils are divided into an upper unit and a lower unit. The upper unit and lower unit are fixed by a band or the like to allow them to be mounted on an object to be examined. The signals detected by the respective surface coils are sent to a data processing system through independent receiver units and formed into a magnetic resonance image.

A wireless remote control unit (60) that operates in the radio frequency bandwidth is used for interfacing with a sequence control system (B) and an image processing system (C) from within a magnetic resonance suite (A) in the presence of a magnetic field produced by a main magnet assembly (10). The sequence control system and the image processing system are connected with a first wireless transceiver (30) whose antenna (28) is located within a magnetic resonance suite. The first transceiver (30) communicates with the remote control unit (60) and a second transceiver (32) connected with a transmitter (40) and gradient coil amplifiers (34). Resonance signals received by a radio frequency coil (46) are communicated to the first transceiver (30) by the second transceiver (32) or by a transceiver (46′) mounted on the receiving coil. The receiver coil transceiver also engages in a handshake protocol to identify itself.

An antenna and shield apparatus for detecting phenomenal signals using nuclear and electronic resonance detection technology, comprising: a transmit and receive antenna, an electric field shield 60 and an outer shield 52. The antenna is a multiple parallel loop transmit-receive antenna forming a main coil assembly 11 having a plurality of loop segments 20 optionally interconnected by connectors in the form of conducting bars 10, relays 16, or nothing. The electric field shield 60 comprises an inner sleeve of conducting material 60, 68 disposed on the inside of the coil assembly 11 for shielding the electric field emanating from the coil assembly 11 from the target volume circumscribed by the assembly. The outer shield 52 comprises a central screen portion 55, waveguides 57 at either end thereof and a sloping channel portion for interconnecting the two. The coil assembly 11 and the electric field shield 60 are housed within the outer shield 52.