30 results about "High field magnetic resonance imaging" patented technology

The present invention relates to systems and methods of performing magnetic resonance imaging (MRI) in awake animals. The invention utilizes head and body restrainers to position an awake animal relative to a radio frequency dual coil system operating in a high field magnetic resonance imaging system to provide images of high resolution without motion artifact.

As the static magnetic field used in Magnetic Resonance Imaging (“MRI”) instruments increases the resonance frequency also increases. Consequently, the signal lost due to the coil becomes an issue. To compensate for this loss, it is possible to use an active device, such as a diode, a transistor, etc., with the radio frequency coil, MRI arrangement and method according to exemplary embodiments of the present invention to generate negative resistance to cancel the coil loss resistance. In this manner, the efficiency of the RF coil at high frequency can be improved.

For example, the present disclosure provides exemplary embodiments of a coil arrangement that can include, e.g., a plurality of elements which can be provided at an angle from one another. The angle can be selected to effectuate an imaging of a target region of interest at least one of a predetermined depth or range of depths, for example. In certain exemplary embodiments according to the present disclosure, the angle can be selected to effectuate an exemplary predetermined transmit efficiency for at least one of the elements. Additionally, the exemplary angle can be selected to effectuate a predetermined receive sensitivity for at least one of the elements. Further, according to certain exemplary embodiments of a coil arrangement in according to the present disclosure, the angle can be adjusted manually and / or automatically.

As the static magnetic field used in Magnetic Resonance Imaging (“MRI”) instruments increases the resonance frequency also increases. Consequently, the signal lost due to the coil becomes an issue. To compensate for this loss, it is possible to use an active device, such as a diode, a transistor, etc., with the radio frequency coil, MRI arrangement and method according to exemplary embodiments of the present invention to generate negative resistance to cancel the coil loss resistance. In this manner, the efficiency of the RF coil at high frequency can be improved.

A half-volume quadrature TEM coil high field (>3 T) imaging applications. This novel coil produces a sufficiently large homogeneous B1 field region for the use as a volume coil. It provides superior transmission efficiency, resulting in significantly lower power deposition, as well as greater sensitivity and improved patient comfort and accessibility compared with conventional full-volume coils. Additionally this coil compensates the RF penetration artifact that distorts high-field images recorded with linear surface and volume coils. These advantages make it potentially possible to apply the device as an efficient transmit / receive body coil at high fields, where the use of the full-volume coils is complicated by the excessive power deposition and low sensitivity.

The invention discloses a small animal radio frequency coil for a clinical super-high field magnetic resonance imaging system. The small animal radio frequency coil is mainly composed of a single-channel transmitting and receiving integrated antenna and a plurality of receiving antennas. The receiving antennas form multiple channels. All the receiving antennas are distributed on the periphery of the transmitting and receiving integrated antenna in annular arrays and geometrically overlapped with the transmitting and receiving integrated antenna. Through the generation induction, the radio frequency decoupling among the antenna channels is enhanced; the coverage of the transmitting and receiving integrated antenna is smaller than the sum of the coverage of all the receiving antennas, and therefore the signal excitation of the small imaging area is realized; the receiving antennas have the parallel imaging function of the clinical magnetic resonance imaging system, the scanning time canbe easily shortened, and the image quality can be easily improved; the transmitting and receiving integrated antenna and the receiving antennas are all connected with front amplifiers respectively after being connected with a capacitor in series. By means of the coil, the requirement for flexibly placing the coil for imaging of small animals with different sizes can be met.

An array coil to achieve more uniform RF excitation for high field magnetic resonance imaging. In the preferred embodiment, the array coil has a plurality of transmit-composite elements distributed around the object to be imaged. A composite element comprises up to three current loops preferably orthogonal to each another. The array coil has the capability to shape the distribution of all three orthogonal components (x, y, and z) of the RF B1 field.

An array coil to achieve more uniform RF excitation for high field magnetic resonance imaging. In the preferred embodiment, the array coil has a plurality of transmit-composite elements distributed around the object to be imaged. A composite element comprises up to three current loops preferably orthogonal to each another. The array coil has the capability to shape the distribution of all three orthogonal components (x, y, and z) of the RF B1 field.

A half-volume quadrature TEM coil high field (>3 T) imaging applications. This novel coil produces a sufficiently large homogeneous B1 field region for the use as a volume coil. It provides superior transmission efficiency, resulting in significantly lower power deposition, as well as greater sensitivity and improved patient comfort and accessibility compared with conventional full-volume coils. Additionally this coil compensates the RF penetration artifact that distorts high-field images recorded with linear surface and volume coils. These advantages make it potentially possible to apply the device as an efficient transmit / receive body coil at high fields, where the use of the full-volume coils is complicated by the excessive power deposition and low sensitivity.

The invention provides a method for optimizing radio frequency pulses in a fast spin echo pulse sequence. According to the method, spin echoes and stimulated echoes are separated by utilizing the difference of the action of a disturbed phase gradient on the spin echoes and the stimulated echoes, and the stimulated echoes or the spin echoes disappear through reverse pulses with different tilt angles, so that independent adjustment of the spin echoes and the stimulated echoes is realized; and the phase of the reverse pulse is optimized by using the relationship among the spin echoes, stimulatedechoes and reverse pulses in phase. According to the method, the influence of radio frequency field heterogeneity on the FSE sequence parameter optimization process can be reduced, the radio frequencypulse optimization efficiency is improved, and the method is particularly suitable for a high-field magnetic resonance imaging system.

The subject invention pertains to methods and apparatus for producing excitation for magnetic resonance imaging (MRI) from a plurality of local exciting elements such that each local exciting element's excitation is independent of the other local exciting elements' excitation. The methods and apparatus of the subject invention can be utilized in magnetic resonance imaging (MRI) and in magnetic resonance spectroscopy (MRS), where MRI produces a magnitude for each pixel that combines many frequency components, typically for magnitude images, and MRS produces a spectrum of outputs over a range of frequencies for each pixel, typically a spectral output. The subject method and apparatus can be utilized for exciting proton, and / or other imaging materials relating to spin magnetization, such as, but not limited to, phosphorous, carbon, and fluorine. In a specific embodiment, the subject invention achieves the independence of the local exciting elements' excitations via serial means, such that excitation is produced by each local exciting element at a different time than the other local exiting elements.

A magnetic resonance imaging apparatus having a static magnetic field source, a plurality of radio frequency magnetic field sources and a plurality of gradient magnetic field sources for generating a gradient magnetic field is provided. The static magnetic field source generates a static magnetic field for aligning a spin vector of an object in a direction of the magnetic field and plurality of radio frequency magnetic field sources generate a radio frequency magnetic field for rotating the spin vector by an angle. The apparatus further includes a processor for generating a plurality of radio frequency excitation pulses for the plurality of radio frequency magnetic field sources and a plurality of gradient excitation pulses for the plurality of gradient magnetic field sources. The second half of each of the plurality of radio frequency excitation pulses comprises a time-reversed first half of a respective one of the plurality of radio frequency excitation pulses and the second half of each of the plurality of gradient excitation comprises a time-reversed and sign-reversed first half of a respective one of the plurality of gradient excitation pulses. The average value of each of the plurality of gradient excitation pulses is zero.

The subject invention pertains to methods and apparatus for producing excitation for magnetic resonance imaging (MRI) from a plurality of local exciting elements such that each local exciting element's excitation is independent of the other local exciting elements' excitation. The methods and apparatus of the subject invention can be utilized in magnetic resonance imaging (MRI) and in magnetic resonance spectroscopy (MRS), where MRI produces a magnitude for each pixel that combines many frequency components, typically for magnitude images, and MRS produces a spectrum of outputs over a range of frequencies for each pixel, typically a spectral output. The subject method and apparatus can be utilized for exciting proton, and / or other imaging materials relating to spin magnetization, such as, but not limited to, phosphorous, carbon, and fluorine. In a specific embodiment, the subject invention achieves the independence of the local exciting elements' excitations via serial means, such that excitation is produced by each local exciting element at a different time than the other local exiting elements.

The invention discloses a rodent small animal imaging device for an ultrahigh-field magnetic resonance imaging system. The rodent small animal imaging device comprises a cylindrical coil supporting shell, a hydrogen nucleus transmitting and receiving coil and a non-hydrogen nucleus transmitting and receiving coil, wherein the hydrogen nucleus transmitting and receiving coil and the non-hydrogen nucleus transmitting and receiving coil are arranged in a shell wall interlayer of the coil supporting shell; each of the hydrogen nucleus transmitting and receiving coil and the non-hydrogen nucleus transmitting and receiving coil comprises a front coil unit and a rear coil unit which are both of an annular structure and are arranged at intervals, and a plurality of straight wires which are connected with the front coil unit and the rear coil unit and are arranged at intervals in the circumferential direction. The hydrogen nucleus transmitting and receiving coil and the non-hydrogen nucleus transmitting and receiving coil are arranged in a sleeving mode, and each straight wire of the hydrogen nucleus transmitting and receiving coil is arranged between two corresponding adjacent straight wires on the non-hydrogen nucleus transmitting and receiving coil. The device provided by the invention can obtain a magnetic resonance image with higher quality and more comprehensive information.

The invention provides a tissue separation imaging method based on inversion recovery, adopting scanning imaging sequence to excite an imaging object, and carrying out image sampling on the imaging object in different inversion times. Each sampling image comprises an image of each tissue, the time of sampling is determined by kind quantity of tissues to be separated and imaged are contained in the imaging object, and a pure tissue image of each tissue is obtained through simultaneous solution according to each sampling image data and proportion relation occupied by each tissue image data in each sampling image. The method is insensitive to the nonuniformity of a magnetic field, obtains the image with higher SNR through the separation imaging, can realize simultaneous separation imaging of multiple tissues, and is widely applied to various low, middle and high magnetic field MR imaging systems.

In a high field magnetic resonance imaging apparatus and a method for obtaining signals having a high signal-to-noise ratio with the receiving coil thereof, the apparatus has at least a basic magnet and a receiving coil, the basic magnet generating a basic magnetic field, and the receiving coil being disposed within the basic magnetic field and forming an accommodating cavity. The accommodating cavity of the receiving coil is perpendicular to the direction of the basic magnetic field and is positioned in the field of view of the apparatus. The receiving coil is a loop type coil. The apparatus can further have a bracket for fixing the receiving coil. In the method, a receiving coil is used to receive signals in a magnetic field, wherein the receiving coil is perpendicular to the direction of the magnetic field. By using the apparatus and the corresponding method since the receiving coil can have a loop type design, the signal-to-noise ratio is increased. Moreover, the receiving coil can be disposed at a position closer to the center of the field of view, so that the imaging quality is improved.

A magnetic resonance imaging apparatus having a static magnetic field source, a plurality of radio frequency magnetic field sources and a plurality of gradient magnetic field sources for generating a gradient magnetic field is provided. The static magnetic field source generates a static magnetic field for aligning a spin vector of an object in a direction of the magnetic field and plurality of radio frequency magnetic field sources generate a radio frequency magnetic field for rotating the spin vector by an angle. The apparatus further includes a processor for generating a plurality of radio frequency excitation pulses for the plurality of radio frequency magnetic field sources and a plurality of gradient excitation pulses for the plurality of gradient magnetic field sources. The second half of each of the plurality of radio frequency excitation pulses comprises a time-reversed first half of a respective one of the plurality of radio frequency excitation pulses and the second half of each of the plurality of gradient excitation comprises a time-reversed and sign-reversed first half of a respective one of the plurality of gradient excitation pulses. The average value of each of the plurality of gradient excitation pulses is zero.

The invention relates to a method for adjusting tuning curve display and a display interaction device. Firstly, curve information of a tuning curve is obtained, and then if it is determined that the curve information of the to-be-displayed tuning curve is not within a set information range, layout information of the to-be-displayed tuning curve in a display interface is adjusted, and the adjusted tuning curve is displayed in the display interface. According to the method for adjusting the tuning curve display provided by the invention, the layout information of the tuning curve in the display interface can be adjusted according to the curve information of the tuning curve, so that the tuning curve in the display interface can be clearer and more visual, and a user can conveniently adjust the ultrahigh-field magnetic resonance imaging equipment to a better state.

The invention provides a tissue separation imaging method based on inversion recovery, adopting scanning imaging sequence to excite an imaging object, and carrying out image sampling on the imaging object in different inversion times. Each sampling image comprises an image of each tissue, the time of sampling is determined by kind quantity of tissues to be separated and imaged are contained in theimaging object, and a pure tissue image of each tissue is obtained through simultaneous solution according to each sampling image data and proportion relation occupied by each tissue image data in each sampling image. The method is insensitive to the nonuniformity of a magnetic field, obtains the image with higher SNR through the separation imaging, can realize simultaneous separation imaging ofmultiple tissues, and is widely applied to various low, middle and high magnetic field MR imaging systems.

The invention belongs to the technical field of magnetic resonance imaging, and particularly relates to a high-field permanent magnet magnetic resonance imaging magnet system for magnetic focusing and curved surface correction. The magnet system comprises a magnetic yoke, main magnetic steel, non-spherical curved-surface magnetic poles, plugging magnetic steel and side magnetic steel, wherein the non-spherical curved-surface magnetic poles are two saddle-type rotary curved surfaces, have the same shapes and are symmetrically distributed at the center of the magnetic yoke; two pieces of main magnetic steel are respectively positioned behind the two magnetic poles; the plugging magnetic steel is deviated from the center position and is respectively positioned behind the two magnetic poles and positioned on the two side surfaces of the main magnetic steel; the side magnetic steel is respectively positioned on the side surfaces of the two magnetic poles and arranged on the outer side of the plugging magnetic steel; the main magnetic steel and the plugging magnetic steel are made of permanent magnet materials with high coercive force; the side magnetic steel is made of permanent magnet materials with higher coercive force; the coercive force of the side magnetic steel is over 20 percent higher than that of the main magnetic steel. By the adoption of a magnetic focusing technology, high-field 1.2-2.1T field intensity can be achieved; the uniform field of a magnet is corrected by the curved surfaces, so that extremely high space efficiency and more than ten times of uniformity are achieved.

The invention discloses a magnetic resonance spectrometer and a magnetic resonance imaging system. The magnetic resonance spectrometer comprises a micro-control unit which communicates with a gradient signal generation board, a radio frequency pulse signal generation board and a receiver and is used for controlling operation of the gradient signal generation board, the radio frequency pulse signal generation board and the receiver through data sent by an upper computer and sending magnetic resonance signals obtained by the receiver to the upper computer, wherein the radio frequency pulse signal generation board is used for sending a pulse signal to a radio frequency general coil to excite the radio frequency general coil to generate a radio frequency magnetic field so as to enable a detected object to generate a magnetic resonance phenomenon, the radio frequency pulse signal generation board is provided with at least two radio frequency emission sources and a detection module used for detecting a radio frequency energy deposition value, and the receiver is used for receiving magnetic resonance signals of a radio frequency receiving coil. With the magnetic resonance spectrometer and the magnetic resonance imaging system of the invention adopted, the problems of poor imaging quality and potential safety hazards of a high-field magnetic resonance imaging system in the prior art are solved.

The invention discloses a preparation method of an antiferromagnetic nanoparticle biological imaging probe, which comprises the following steps of: dissolving ferric acetylacetonate and platinum acetylacetonate in a mixed solution of oleylamine, oleic acid and dibenzyl ether, reacting for 3-60 minutes under the inert atmosphere condition of 200-300 DEG C, and precipitating a poor solvent to obtain oil-phase antiferromagnetic nanoparticles; performing hydrophilic surface modification on the oil-phase ferromagnetism nanoparticles by using hydrophilic molecules by adopting a ligand exchange method to obtain water-phase antiferromagnetic nanoparticles; and performing a chemical connection reaction on the water-phase antiferromagnetic nanoparticles, and performing targeted surface modification by using a targeted ligand to obtain the antiferromagnetic nanoparticle biological imaging probe. The invention also discloses the antiferromagnetic nanoparticle biological imaging probe prepared by the preparation method and application of the antiferromagnetic nanoparticle biological imaging probe in preparation of a tumour magnetic resonance imaging contrast agent. The antiferromagnetic nanoparticle biological imaging probe has a good high-field magnetic resonance imaging effect, and can be used for performing accurate noninvasive detection on tiny tumours in a living body.

In a high field magnetic resonance imaging apparatus and a method for obtaining signals having a high signal-to-noise ratio with the receiving coil thereof, the apparatus has at least a basic magnet and a receiving coil, the basic magnet generating a basic magnetic field, and the receiving coil being disposed within the basic magnetic field and forming an accommodating cavity. The accommodating cavity of the receiving coil is perpendicular to the direction of the basic magnetic field and is positioned in the field of view of the apparatus. The receiving coil is a loop type coil. The apparatus can further have a bracket for fixing the receiving coil. In the method, a receiving coil is used to receive signals in a magnetic field, wherein the receiving coil is perpendicular to the direction of the magnetic field. By using the apparatus and the corresponding method since the receiving coil can have a loop type design, the signal-to-noise ratio is increased. Moreover, the receiving coil can be disposed at a position closer to the center of the field of view, so that the imaging quality is improved.

The invention discloses a bionic nano diagnosis and treatment agent for ultrahigh field magnetic resonance imaging and a preparation method thereof, and the nano diagnosis and treatment agent Ho-MPDA is prepared by doping water-soluble dopamine (PDA) with holmium ions (Ho < 3 + >) through a method of doping metal before polymerization. The Ho-MPDA has an obvious T2 contrast enhancement effect under the ultrahigh field intensity of 7.0 T, and the transverse electron relaxation time is obviously shortened. And the transverse relaxation rate T2 (102.71 mM <-1 > S <-1 >) of the Ho-MPDA under the ultrahigh field intensity of 7.0 T is 4.02 times that of a T2 contrast agent (25.52 mM <-1 > S <-1 >), and the imaging effect is greatly improved. Meanwhile, the polydopamine carrier has good biocompatibility, excellent photo-thermal conversion capacity and good light stability, and photo-thermal therapy is achieved under the guidance of ultrahigh-field magnetic resonance imaging.

The invention relates to a material for use as a pad in high field and / or very high field magnetic resonance imaging instrument, comprising at least one polar solvent having a melting point of 14° C. to 50° C., a dispersant and a dielectric charge. The invention relates also to a pad used in field of high field and / or very high field magnetic resonance imaging made of at least such a material.

A small animal radio-frequency coil used in a clinical ultra-high field magnetic resonance imaging system, consisting of a single-channel transmitting and receiving integrated antenna (1) and multiple receiving antennas (2). The multiple receiving antennas (2) form multiple channels. All the receiving antennas (2) are arranged in a circular array on the outer periphery of the transmitting and receiving integrated antenna (1) and geometrically overlap with the transmitting and receiving integrated antenna (1), and the radio-frequency decoupling between the antenna channels is enhanced by generated mutual inductance. The coverage area of the transmitting and receiving integrated antenna (1) is less than the sum of the coverage areas of all the receiving antennas (2), thereby achieving signal excitation in a small imaging area. The receiving antennas (2) have a parallel imaging function of a clinical magnetic resonance imaging system, thereby helping to shorten the scanning time and improve the image quality. The transmitting and receiving integrated antenna (1) and the receiving antennas (2) are each connected in series with a capacitor and connected to its respective preamplifier (3). The requirements for flexible coil placement for imaging of small animals of different sizes can be satisfied.

The invention discloses a primate radio frequency coil device for a clinical ultrahigh-field magnetic resonance system. The primate radio frequency coil device comprises an animal fixing base for fixing an animal to be tested, a helmet-shaped receiving coil supporting shell which is connected with the animal fixing base through a universal connecting rod and can be worn on the head of the animal to be tested, a radio frequency receiving coil arranged in the receiving coil supporting shell, a transmitting coil supporting shell connected with the animal fixing base through a universal connecting rod and is of an annular structure, and a radio frequency transmitting coil arranged in the transmitting coil supporting shell. According to the primate radio frequency coil device, the positions and angles of the radio frequency transmitting coil and the radio frequency receiving coil can be easily adjusted according to needs, so that the region of interest is located at the position with the best transmitting field uniformity, the problem that the radio frequency transmitting field is not uniform in clinical ultrahigh field magnetic resonance imaging application is solved, and the accuracy of a medical image in the region of interest is effectively improved.