36 results about "Ultra low field" patented technology

The invention provides a gradient coil model correction method for ultra-low field magnetic resonance, and relates to the technical field of gradient coil control in medical imaging equipment, and the method comprises the steps: collecting a real voltage signal d (n) and a real current signal x (n) of a gradient coil in real time, and n represents a sampling moment; a gradient coil model is constructed, the gradient coil model comprises a linear model constructed based on an adaptive filtering algorithm and a nonlinear model constructed based on a neural network algorithm, and a first prediction voltage signal # imgabs0 # output by the linear model and a second prediction voltage signal # imgabs1 # output by the nonlinear model are determined according to the real current signal x (n); determining a mixed prediction voltage signal # imgabs4 # of the gradient coil model according to the first prediction voltage signal # imgabs2 # and the second prediction voltage signal # imgabs3 #; and updating the weight of the linear model and the weight of the nonlinear model according to the real voltage signal d (n) and the mixed predicted voltage signal # imgabs5 # so as to adapt to gradient coil model correction under complex working conditions.

The invention provides movable ultra-low field magnetic resonance equipment suitable for an operating room, and the equipment comprises a scanning device which comprises an ultra-low field permanent magnet, a gradient coil and a radio frequency coil, the intensity of the magnetic field generated by the ultra-low field permanent magnet is not higher than 100 mT, and the radio frequency coil employs a receiving and transmitting integrated coil; the motion executing mechanism comprises a driving motor and wheels and is used for bearing the scanning device to move to a target position; the sensor device comprises at least one of a camera, a laser radar and an ultrasonic distance sensor, and is configured to sense the surrounding environment of the movable ultra-low field magnetic resonance equipment and the position information of the movable ultra-low field magnetic resonance equipment in the environment; and the motion control unit is configured to send a control instruction to the motion execution mechanism according to a path plan obtained by the sensing information of the sensor device. According to the invention, the moving path of the magnetic resonance equipment is automatically adjusted according to the moving distance and the target position of the magnetic resonance equipment, the automatic and intelligent control of the magnetic resonance equipment is realized, the workload of operators is reduced, and the convenience and safety of the equipment are improved.

The present invention discloses a small ultra-low field nuclear magnetic resonance spectrometer, which includes a sample flow module for driving a liquid sample to flow between a polarization region and a detection region; a hyperpolarization module for polarizing the liquid sample; a probe and sample fixation module for fixing a sample tube in the detection region and a nuclear magnetic detection module; a pulse application module for applying a pulse to the liquid sample to rotate the nuclear magnetization vector of the sample to the transverse direction and perform free evolution of the sample spin; a nuclear magnetic detection module for detecting the free evolution spin signal of the liquid sample and converting it into a voltage signal; a magnetic shielding module for shielding the geomagnetic field to ensure an ultra-low field environment; and a timing control module for controlling the operation of each module and collecting the voltage signal. Through the combination of each module, the detection process of the present invention is carried out in a magnetic shielding environment, eliminating the dependence on a strong magnetic field of a traditional nuclear magnetic resonance spectrometer, effectively reducing the system complexity and cost; making the overall structure simple, small in size, easy to move, and adaptable to nuclear magnetic detection in various environments.

The invention relates to the technical field of ultra-low field magnetic resonance systems, in particular to a battery charge state detection method and system based on closed-loop adaptive ultra-low field MRI, and the method comprises the steps: collecting the phase change of a water molecule H signal caused by the magnetic field disturbance of a to-be-detected battery, and reconstructing a first signal phase image; extracting to obtain a high-information-content area mask, and then performing resampling to obtain a second signal phase image; and inputting the second signal phase image into a state-of-charge detection model to predict a state-of-charge value of the to-be-detected battery. In order to solve the problem that a battery magnetic resonance detection scheme in the prior art needs to adopt a high-field magnetic resonance system and is not beneficial to production line use, detection equipment is replaced with an ultralow-field magnetic resonance system, so that structures such as a shielding room in a traditional magnetic resonance system are omitted, and a high-information-content area is positioned firstly, so that the detection efficiency is improved; and resampling is carried out on the region, so that the imaging precision is improved, and the accuracy of state of charge estimation of the detection model is improved.

The system comprises a magnet unit, an equipment cabinet and an operation transfer bed, the magnet unit is composed of a permanent magnet, a gradient coil and a radio frequency coil, the permanent magnet is of a U-shaped structure, a scanning area with the front face of a patient being completely open is formed, and the gradient coil and the radio frequency coil are arranged in the scanning area. The gradient coil is embedded into the inner side of the magnet to generate a space gradient field, and the radio frequency coil is arranged around the forehead, the head side face and the rear pillow area of a patient to avoid blocking the eyes, the mouth and the nose. The equipment cabinet is arranged below or beside the magnet unit, a gradient power amplifier, a radio frequency power amplifier, a front receiving unit, a spectrometer, a power supply control unit and a rechargeable battery are arranged in the equipment cabinet, and all the modules are electrically connected to form an imaging control system. The surgical transfer bed is slidably connected to the magnet unit for feeding the head of the patient into the imaging area. The system realizes full-open scanning in an ultra-low field environment, is suitable for intraoperative and postoperative monitoring and special patient image examination, and remarkably improves safety, comfort and operability.

An ultra-low field magnetic resonance imaging system and a method thereof are provided. The ultra-low field magnetic resonance imaging system includes means for collecting a down-sampled three-dimensional ultra-low field magnetic resonance data; means for processing a three-dimensional ultra-low field magnetic resonance data to obtain a three-dimensional isotropic ultra-low field magnetic resonance image; and means for processing data, for inputting the three-dimensional isotropic ultra-low field magnetic resonance image into a pre-trained image enhancement model to obtain a full-sampled three-dimensional magnetic resonance enhanced image.

The invention discloses a low-frequency interference magnetic field elimination method and system, and belongs to the technical field of electromagnetism and control. The device mainly comprises a magnetic sensor module used for collecting interference magnetic field signals, a conversion circuit module used for converting the interference magnetic field signals into analog voltage signals, a characteristic frequency band interference signal selection module, an analog signal phase adjustment module, a multi-path characteristic frequency band interference signal addition module, an output gain adjustable module and a power amplification module. A magnetic field generation module and an elimination effect detection feedback module. According to the low-frequency interference magnetic field elimination system, an analog circuit design method is adopted, low-frequency interference magnetic fields of several different frequency bands can be effectively weakened and eliminated, and the low-frequency interference resistance of devices with high low-frequency interference sensitivity such as ultralow-field magnetic resonance imaging equipment can be improved by adjusting system related parameters; and the equipment availability is enhanced.

The invention relates to the technical field of magnetic resonance imaging, in particular to an intra-operative low-field magnetic resonance intelligent navigation method based on preoperative high-field data guidance, which comprises the following steps: acquiring a high-field MRI image of a patient before an operation and extracting a three-dimensional segmentation mask and clinical features of a focus; adjusting according to the clinical features to obtain an intraoperative scanning protocol; and performing low-field magnetic resonance examination during the operation to generate an intra-operation navigation image, and marking focus information. Aiming at the problem that the accuracy of a focus image provided by an ultra-low field system in the operation process in the prior art is not enough, a high-field MRI image collected before the operation is introduced as a reference, scanning sequence parameters of the ultra-low field system used in the operation are dynamically adjusted based on clinical features embodied in the high-field MRI image, a better imaging effect is achieved, and meanwhile, the accuracy of the focus image provided by the ultra-low field system in the operation process is improved. Focus information is marked on the intraoperative navigation image based on the three-dimensional segmentation mask as prior information, so that more refined segmentation of focuses on the intraoperative navigation image is realized, and the surgical requirements are met.

The application discloses a kind of based on N2V and EMI removal algorithm's electromagnetic imaging detection dual denoising method and device, the present application is by introducing N2V algorithm to carry out image noise to the image after initial denoising, and using the image after adding noise to carry out secondary denoising training;Thus, it can utilize secondary denoising model, to the initial denoising nuclear magnetic resonance image secondary denoising processing, to obtain the nuclear magnetic resonance image with better denoising effect, based on this, the present application can be in the case of lacking real image secondary denoising training, realizes the secondary denoising processing of nuclear magnetic resonance image, solves the restriction that image secondary denoising training cannot be carried out in traditional technology due to lack of clean image and noise image pair, whereby, the present application can further improve image quality, applicable in the field of ultra-low field MRI equipment imaging image denoising Large-scale application and popularization.

The invention provides an ultra-low field magnetic resonance imaging integrated circular polarization radio frequency transmit-receive coil, and relates to the ultra-low field magnetic resonance imaging technology, the ultra-low field magnetic resonance imaging integrated circular polarization radio frequency transmit-receive coil comprises a medium substrate, split copper sheet ring structures and split straight copper sheet structures, the medium substrate is a cylindrical structure, the medium substrate is uniformly provided with multiple groups of split copper sheet ring structures, and the split straight copper sheet structures are arranged on the medium substrate. The split straight copper sheet structures are vertically and uniformly arranged on the split copper sheet ring structures, and feed ports are formed in the split copper sheet ring structures and connected with coaxial cables through SMA connectors. According to the invention, the transmitting and receiving of the circularly polarized magnetic field are realized through orthogonal feed and the adjustable element, the circularly polarized magnetic field can obviously improve the received signal strength and realize the effective improvement of the signal-to-noise ratio, the parameterized design is adopted, the flexible adaptation of multiple scenes is supported, and the antenna can be applied to different field strengths by adjusting the parameters of the adjustable capacitor, the adjustable resistor and the like. And the application scene is widened.

The present invention relates to an apparatus (100) and method for investigating a sample by using nuclear magnetic resonance, particularly zero- to ultra-low-field nuclear magnetic resonance, the apparatus (100) comprising: —a magnetically shielded chamber (20) for magnetically shielding the sample from external static magnetic fields; —magnetic field pulse generation means (30) arranged in the magnetically shielded chamber (20) and configured to manipulate nuclear spins present in the sample, thereby causing the sample to produce a magnetic signal; and—at least one magnetoresistive sensor (40) comprising a ferromagnetic material, wherein the at least one magnetoresistive sensor (40) is arranged in the magnetically shielded chamber (20) and configured to detect the magnetic signal produced by the sample.

The application discloses a kind of background field wide-range adjustable ultra-low field nuclear magnetic resonance measuring device, and a kind of background field wide-range adjustable ultra-low field nuclear magnetic resonance measuring method is also disclosed, the present application adopts flat solenoid to realize high background magnetic field requirement and ultra-low ambient magnetic field, flat solenoid can also accommodate more coil and obtain more turns, realize more extensive background field adjustable range;Flat solenoid both ends are stretched outside magnetic shielding module, which can ensure that the magnetic flux line at the end of flat solenoid is connected outside the shielding area, eliminating the problem of background field inhomogeneity generated by ordinary solenoid coil;The present application can eliminate the interference of ambient magnetic field by passive magnetic shielding and active magnetic field compensation, first, the ambient magnetic field is shielded by multiple electromagnetic shielding cylinders, and then the magnetic field opposite to the ambient magnetic field is generated by the shim coil to actively compensate the magnetic field, to offset the interference of ambient magnetic field;The shim coil can also improve the uniformity of the central magnetic field.

The invention discloses a composite four-channel receiving coil for movable magnetic resonance imaging and imaging equipment, the four-channel receiving coil comprises two breast sub-coils and two far-end sub-coils, and the breast sub-coils with multiple turns in a cap-shaped structure are used for imaging a breast area. A multi-turn far-end coil of a butterfly-shaped structure is adopted for imaging an upper root area of a mammary gland, and two sub-coils are orthogonally arranged on corresponding wiring structures respectively and used for mammary gland magnetic resonance imaging in a vertical magnetic field; according to the composite four-channel receiving coil, a pair of cap-shaped asymmetric wiring structures is adopted as a winding framework, a group of breast sub-coils and a group of far-end coils are wound respectively to cover a breast and a breast root area, and decoupling between the breast sub-coils is realized by designing lumped element types and parameter values in a decoupling circuit. According to the ultra-low field mammary gland imaging method, ultra-low field mammary gland imaging with high precision and large imaging range under the vertical magnetic field is realized, and certain reference can be provided for related research in the future.

A system of field cycled magnetic resonance system and a method of operating a field cycled magnetic resonance system are described. In accordance with various embodiments, the disclosed system includes a static field magnet, wherein the magnet is configured to provide a low static external magnetic field to a given field of view, a radio frequency coil, and a field cycling magnet. In accordance with various embodiments, the method includes providing a static field magnet configured to image a tissue sample within a given field of view, applying a low static external magnetic field to the given field of view, providing a radio frequency coil configured to produce cycling radio frequency field, providing a field cycling magnet, altering the low static external magnetic field within the given field of view, and collecting images from the system.

The present invention discloses a vehicle-mounted, ultra-low-field brain magnetic resonance imaging system specifically designed for stroke, which relates to the field of medical magnetic resonance imaging and includes a carriage body, a stretcher disposed within the carriage body, a wheel body connected to the bottom end of the stretcher, a magnetic resonance magnet unit disposed at one end within the carriage body, an equipment cabinet mounted above the magnetic resonance magnet unit, and two chutes disposed at the bottom end of the carriage body, spaced equidistant from the wheel body. The two chutes are parallel to each other, and both have internal locking structures for sliding against the wheel body. The present invention uses a dedicated ultra-low-field brain magnetic resonance imaging system to directly travel to the patient's residence for stroke diagnosis, thereby buying valuable time for the treatment of acute stroke. A clamping structure is designed within the ambulance to clamp the stretcher wheel, allowing the patient's head to enter the magnetic resonance magnet unit more smoothly and accurately as the stretcher continues to move forward.

A nuclear magnetic resonance (NMR) spectrometer includes an array of distinct, separate samples to be tested, a set of optically pumped magnetometers (OPM), an inhomogeneous magnet having a bore configured to accept the array of samples, a zero-to- ultra-low field detection center, a field cycler stage to transport the array of samples between the inhomogeneous magnet and the detection center along a path, the path having a guiding field solenoid; and a computer to control operation of the spectrometer.

The invention provides a power supply system for ultra-low field magnetic resonance, the power supply system comprises a storage battery and a common power supply conversion module, the ultra-low field magnetic resonance further comprises a load end, the load end comprises a gradient system, a radio frequency system, a spectrometer system and a computer console, the power supply system is characterized by comprising the storage battery used for providing a main power supply; the common power supply conversion module is connected with the storage battery, is provided with a high-voltage output unit and a low-voltage output unit, and is used for outputting high voltage from the voltage of the storage battery through the high-voltage output unit and outputting low voltage from the voltage of the storage battery through the low-voltage output unit; the high-voltage output unit is used for supplying power to the gradient system and the radio frequency system; the low-voltage output unit is used for supplying power to the gradient system, the radio frequency system, the spectrometer system and the computer console, the structure of the power supply system is simplified by sharing the power supply conversion module, and the manufacturing cost and the equipment maintenance complexity are reduced.

The present invention belongs to the field of magnetic resonance imaging technology, and its purpose is to provide an ultra-low field magnetic resonance imaging method, system, electronic equipment and product. The present invention reads out the area of ​​the pre-phase gradient Grp and the gradient delay of the readout gradient Gr for each gradient axis of different spokes in an iterative manner, so that the delay difference of the gradients of the two gradient axes read out by the radial acquisition method is as small as possible, and the center of the k space is aligned as much as possible to reduce the offset, so as to reduce the influence caused by the difference in gradient performance, thereby improving the image quality; at the same time, the present invention improves the imaging sequence, and by correcting the fast spin echo sequence, a better imaging effect can be obtained in the ultra-low field, so that the average number can be set to 1 at least, so that denser spokes can be collected, and two cycles are not required while improving the resolution, thereby shortening the scanning time under the premise of ensuring that the image resolution and quality meet the requirements.

The application relates to an ultra-low-field magnetic resonance imaging noise suppression method and an ultra-low-field magnetic resonance imaging system. The method comprises the following steps: acquiring original magnetic resonance signals of a main imaging signal channel and reference noise signals of a plurality of reference channels; dividing time periods according to a scanning sequence and generating synchronization control signals corresponding to different time periods; in response to a first synchronization control signal, entering a training mode in a non-signal acquisition window of the scanning sequence, wherein the training mode comprises updating weight coefficients of an adaptive filter set based on the reference noise signals and the original magnetic resonance signals; in response to a second synchronization control signal, entering a scanning mode in a signal acquisition window of the scanning sequence, wherein the scanning mode comprises freezing or reducing the update speed of the weight coefficients of the adaptive filter set, and using the updated weight coefficients to perform noise cancellation on the original magnetic resonance signals and output purified magnetic resonance signals. The image signal-to-noise ratio of the ultra-low-field magnetic resonance imaging is improved.

The present disclosure provides systems and methods for deep learning super-resolution training and / or image generation for low and ultra-low field magnetic resonance imaging. In some aspects, a method includes obtaining a first image of a brain with a low field strength magnetic resonance imaging system. The first image has a first resolution. The method further includes obtaining a deep learning brain model based on a high field strength image. The deep learning brain model can be configured to be applied by a neural network comprising a plurality of layers. The method further includes applying the deep learning brain model to the first image to generate a second image of the brain. The second image has a second resolution, and the second resolution is greater than the first resolution.

The present invention provides an automatic control method for a gradient drive system for ultra-low field magnetic resonance imaging, relating to the technical field of ultra-low field magnetic resonance imaging systems. The automatic control method comprises determining a target switching frequency of the gradient drive system; determining a corresponding target sampling period and initial control parameters of the gradient drive system based on the target switching frequency; determining a target control parameter of the gradient drive system based on a target current and the initial control parameter; and determining a target duty cycle signal of the gradient drive system based on the target control parameter, thereby dynamically adjusting the switching frequency of the gradient drive system and reducing switching losses.

The present disclosure provides systems and methods for deep learning super-resolution training and / or image generation for low-field and ultra-low-field magnetic resonance imaging. In some aspects, the method includes acquiring a first image of a brain using a low-field strength magnetic resonance imaging system. The first image has a first resolution. The method further includes acquiring a deep learning brain model based on the high-field strength image. The deep learning brain model can be configured to be applied by a neural network comprising multiple layers. The method further includes applying the deep learning brain model to the first image to generate a second image of the brain. The second image has a second resolution, the second resolution being greater than the first resolution.

The invention discloses a method and a device for identifying and eliminating low-frequency strong interference noise of a magnetic resonance system, which are characterized in that after being processed by a conventional self-adaptive noise reduction method, signals in a k space which is not influenced by low-frequency strong EMI (Electro-Magnetic Interference) along frequency and phase encoding directions are smooth, and the low-frequency strong EMI is discontinuous in the phase encoding direction, so that the low-frequency strong interference noise can be identified and eliminated. According to the characteristic that the signal is in a peak shape in time sequence, low-frequency strong EMI post-processing identification and elimination are carried out on the signal after self-adaptive noise reduction; therefore, the low-frequency strong interference noise in the nuclear magnetic resonance signal can be removed, so that the quality of nuclear magnetic resonance imaging is improved; therefore, the method is very suitable for large-scale application and popularization in the field of ultra-low field nuclear magnetic resonance.

The invention provides a gradient power amplifier for ultra-low field magnetic resonance and ultra-low field magnetic resonance, and relates to the technical field of medical instruments.The gradient power amplifier comprises a power control end and three sets of power controllers, and each set of power controller is connected with a gradient coil in the orthogonal direction; each group of power controllers comprises an H-bridge gradient inverter circuit, an output filter and a switch controller, wherein the H-bridge gradient inverter circuit comprises four GaN switches; the high-voltage power supply end is used for providing a direct-current high-voltage power supply, and the high-voltage power supply end is connected with the power control end; and the heat dissipation device is arranged at the power control end and is used for carrying out heat dissipation on all the H-bridge gradient inverter circuits. The number of components and wiring complexity of the gradient power amplifier are reduced, the integration level is high, the size is small, and the gradient control precision is high.

The invention relates to the technical field of magnetic resonance, in particular to an ultra-low field mobile magnetic resonance system power supply noise reduction device which comprises a public network power supply access module used for being connected with a public power grid. The controller is in communication connection with the magnetic resonance spectrometer and is used for receiving the scanning trigger signal; the off-line power supply module is used for directly supplying power to the magnetic resonance system, the off-line power supply module is composed of a plurality of single-type energy storage elements, and the energy storage elements are arranged to be a super capacitor bank or a lithium battery pack; and the power supply switching module is configured to cut off the electrical connection between the public network power supply and the off-line power supply module during the scanning period, so that the off-line power supply module can supply power to the radio frequency coil. The controller is arranged, the power supply switching module is matched with the off-line power supply module, the continuous operation reliability of the system is improved to 99.5% from 89% of a traditional scheme, and the application range of mobile medical equipment in emergency rescue, patrol in remote areas and other scenes is greatly expanded.

The present invention provides a gradient coil model correction method for ultra-low field magnetic resonance imaging, which relates to the technical field of gradient coil control in medical imaging equipment. The method comprises: real-time acquisition of a real voltage signal d(n) and a real current signal x(n) of the gradient coil, where n represents a sampling time; constructing a gradient coil model, wherein the gradient coil model comprises a linear model constructed based on an adaptive filtering algorithm and a nonlinear model constructed based on a neural network algorithm, wherein a first predicted voltage signal #imgabs0# output by the linear model and a second predicted voltage signal #imgabs1# output by the nonlinear model are determined according to the real current signal x(n); a mixed predicted voltage signal #imgabs4# of the gradient coil model is determined according to the first predicted voltage signal #imgabs2# and the second predicted voltage signal #imgabs3#; and, according to the real voltage signal d(n) and the mixed predicted voltage signal #imgabs5#, the weights of the linear model and the weights of the nonlinear model are updated to adapt to gradient coil model correction under complex working conditions.

A low-frequency magnetic field interference active cancellation device for ultra-low field magnetic resonance imaging (MRI) is characterized by comprising: a magnetic field sensing subsystem, including: a three-axis fluxgate magnetometer for acquiring changes in the external environmental magnetic field; a miniature reverse solenoid for generating a static bias magnetic field opposite to the direction of the leakage magnetic field of the main magnetic field of the ultra-low field MRI device, thereby canceling the net magnetic field at the probe to near zero and enabling the three-axis fluxgate magnetometer to operate in the linear region; a signal processing and control subsystem electrically connected to the magnetic field sensing subsystem, including a digital signal processor (DSP) that executes a PID control algorithm to calculate a compensation control quantity based on the negative feedback error signal; and a magnetic field execution subsystem electrically connected to the signal processing and control subsystem, including a ceiling coil and a floor coil, for generating a compensation magnetic field uniformly distributed along the direction of the main magnetic field within the imaging area of ​​the ultra-low field MRI device.

The invention provides an automatic control method of a gradient driving system for ultralow-field magnetic resonance, and relates to the technical field of ultralow-field magnetic resonance imaging systems.The automatic control method comprises the steps that the target switching frequency of the gradient driving system is determined; determining a corresponding target sampling period and an initial control parameter of the gradient driving system according to the target switching frequency; determining a target control parameter of the gradient driving system according to a target current and the initial control parameter; and determining a target duty ratio signal of the gradient driving system according to the target control parameter, and realizing dynamic adjustment of the switching frequency of the gradient driving system, thereby reducing the switching loss.

A system of field cycled magnetic resonance system and a method of operating a field cycled magnetic resonance system are described. In accordance with various embodiments, the disclosed system includes a static field magnet, wherein the magnet is configured to provide a low static external magnetic field to a given field of view, a radio frequency coil, and a field cycling magnet. In accordance with various embodiments, the method includes providing a static field mag-net configured to image a tissue sample within a given field of view, applying a low static external magnetic field to the given field of view, providing a radio frequency coil configured to produce cycling radio frequency field, providing a field cycling magnet, altering the low stat-ic external magnetic field within the given field of view, and collecting images from the system.

The invention discloses a deep learning method and system for improving the signal-to-noise ratio of an ultra-low field magnetic resonance image. Noise modeling is carried out according to the characteristics of the ultra-low field magnetic resonance image; selecting a clear magnetic resonance image data set, and making a corresponding noise image data set; a deep learning network model is built, and multi-scale feature extraction and an attention mechanism module are combined; training a deep learning network model by using the data set, and setting a proper learning rate and an optimizer until a loss function is converged; inputting test set data into the trained network model to obtain a denoised image, and comparing the denoised image with other methods; and inputting an actually measured ultra-low field magnetic resonance image into the trained model, outputting a dropped image, and verifying the dropped image. Compared with a traditional noise reduction method and an existing deep learning method, the method has the advantages that the pertinence to the ultra-low field magnetic resonance image is higher, and the noise reduction effect is better.