G01R33/44

MRI METHOD FOR CALCULATING DERIVED VALUES FROM B0 AND B1 MAPS

The invention provides for a magnetic resonance imaging system (100, 300, 100) for acquiring magnetic resonance data (110, 1104) from a subject (118) within an imaging zone (108). The magnetic resonance imaging system comprises a memory (136) for storing machine executable instructions (160, 162, 164, 166, 316) and pulse sequence data (140, 1102). The pulse sequence data comprises instructions for controlling the magnetic resonance imaging system to acquire magnetic resonance data according to a magnetic resonance imaging method. The magnetic resonance imaging system further comprises a processor (130) for controlling the magnetic resonance imaging system. Execution of the machine executable instructions causes the processor to: acquire (1200) the magnetic resonance data by controlling the magnetic resonance imaging system with the pulse sequence data; calculate (1202) a B0 inhomogeneity map (148) by analyzing the magnetic resonance data according to the magnetic resonance imaging method, calculate (1204) a B1 phase map (150) and/or a B1 amplitude map (1106) by analyzing the magnetic resonance data according to the magnetic resonance imaging method; and calculate (1206) a second derivative (1110) of the B1 phase map and/or a second derivative of the B1 magnitude map 1 and/or a second derivative of the B0 in homogeneity map in at least one predetermined direction. The second derivative is calculated using a corrected voxel size in the at least one predetermined direction, wherein the corrected voxel size is calculated using a correction factor calculated from the derivative of the B0 inhomogeneity map.

SYSTEM AND METHOD FOR TISSUE CHARACTERIZATION USING FAST QUANTITATIVE SPIN-LOCK MAGNETIZATION TRANSFER IMAGING
20230236273 · 2023-07-27 · ·

Systems and methods for fast and robust quantification of magnetization transfer (MT) use off-resonance spin-lock MRI with as few as two or three image acquisitions. Each image acquisition can be performed using an off-resonance spin-lock pulse having a different RF amplitude and frequency offset. A parameter representing the difference of the relaxation rate in the rotating frame between the acquisitions can be computed. This parameter can be used to compute other parameters of magnetization transfer.

Systems and methods for low-field fast spin echo imaging

A magnetic resonance imaging (MRI) system and method for acquiring magnetic resonance (MR) images using a pulse sequence implementing driven equilibrium and quadratic phase cycling techniques is provided. The method includes, during a pulse repetition period of a pulse sequence and using a quadratic phase cycling scheme, applying a first RF pulse to deflect a net magnetization vector associated with the subject from a longitudinal plane into a transverse plane; after applying the first RF pulse, applying a first sequence of RF pulses each of which flips the net magnetization vector by approximately 180 degrees within the transverse plane; and after applying the first sequence of RF pulses, applying a second RF pulse to deflect the net magnetization vector from the transverse plane to the longitudinal plane.

MAGNETIC RESONANCE IMAGING APPARATUS, IMAGE GENERATING METHOD AND COMPUTER-READABLE NON-VOLATILE STORAGE MEDIUM STORING MEDICAL IMAGE PROCESSING PROGRAM

An MRI apparatus according to an embodiment includes sequence controlling circuitry, in a first transition period, repeating application of a first MT pulse and acquisition of a first MR signal to a first frequency region being a part of a k-space; in the first steady state, repeating application of the first MT pulse and acquisition of a second MR signal to a second frequency region of the k-space, frequency in second frequency region being lower than frequency in the first frequency region; and in a second transition period, repeating application of a second MT pulse and acquisition of a third MR signal to a third frequency region being another part of the k-space, frequency in the third frequency region being higher than the frequency in the second frequency region, and processing circuitry generating one MR image on basis of the first, second, and third MR signal.

Methods and systems for estimating transmit attenuation for a magnetic resonance imaging scan

Various methods and systems are provided for correcting transmit attenuation of an amplifier of a transmit radio frequency (RF) coil for use in a magnetic resonance imaging (MRI) system. In one example, a method includes setting a reference value of transmit attenuation for an amplifier of a transmit radio frequency (RF) coil, acquiring a three-dimensional B.sub.1 field map with the transmit attenuation set at the reference value, determining a plurality of mean flip angles for a plurality of slice locations in a pre-scan imaging volume from the B.sub.1 field map, determining a transmit attenuation correction value for each of the slice locations based on a prescribed flip angle and the mean flip angle determined for the respective slice location, correcting the reference value of transmit attenuation with the transmit attenuation correction value at each of the slice locations to obtain a final value of transmit attenuation for each of the slice locations, and performing an MRI scan with the transmit attenuation set at the value.

Information processing apparatus and information processing method

An information processing apparatus according to an embodiment includes a processing circuit. The processing circuit acquires a measurement field corresponding to a spatial distribution of a predetermined physical quantity in a subject of measurement. The processing circuit calculates an unknown quantity in the subject of measurement based on a first equation between the measurement field and the unknown quantity having spatial dependence, and on the acquired measurement field. The first equation is one that is acquired based on a second equation expressing a dual field divergence of which can be expressed using the measurement field, by using the measurement field and the unknown quantity, and on the Helmholtz decomposition of the dual field.

Method for determining the degree of cure in forages
11692955 · 2023-07-04 · ·

A method for determining the degree of cure in forages using a nuclear magnetic resonance (NMR) technique. An NMR instrument is used to determine the amount of bound moisture (typically called stem moisture) and free moisture (typically called dew moisture) the degree of which can be used to determine how cured the forage is. This method represents an improvement on the traditional ways of determining how cured a forage is. The traditional ways have been by twisting a bunch of forage in ones hands or using a mechanical method (Hammer of fingernail) to determine if there is too much stem moisture in the stem nodes. The method can be applied using a portable instrument or building the instrument into a forage harvesting machine such as a hay baler.

Magnetic resonance detection (MRD) system for and methods of detecting and classifying multiple chemical substances

A magnetic resonance detection (MRD) system for and methods of detecting and classifying multiple chemical substances is disclosed. In one example, the presently disclosed MRD system is a nuclear quadrupole resonance (NQR) detection system that provides multi-frequency operation for substantially full coverage of the explosive NQR spectrum using a broadband transmit/receive (T/R) switch (or duplexer) and a single multi-frequency radio frequency (RF) transducer. More particularly, the MRD system provides a frequency-agile system that can operate over a wide band of frequencies or wavelengths. Further, a method of detecting and classifying various chemical substances is provided that includes pulse sequencing with “frequency hopping,” phase cycling for reducing or substantially eliminating background noise, and/or a process of mitigating amplitude modulation (AM) radio interference.

Hybrid multiferroic nanoparticles as MRI contrast agent for sensing of electric fields in a human body

An apparatus includes a plurality of particles, wherein each particle contains a plurality of magnetizable (for example, ferromagnetic) and ferroelectric materials in fixed physical relationship (for example, physical contact) with one another. A method and apparatus measure magnetic fields arising from or within the plurality of particles.

NMR Measurement Unit Fixable Within A Process Channel

The invention relates to an NMR system, and more particularly to an NMR measurement unit including a flow channel for separating a sample from a fluid stream in a process channel, a magnet arranged relative to flow channel for creating a magnetic field in part of flow channel, a coil arranged relative to flow channel for exciting NMR active nuclei of the sample in flow channel and for receiving the frequency pulse that returns to coil from NMR active nuclei, a frame comprising a fastening flange for sealing NMR measurement unit to process channel and a chamber that is closed relative to fluid stream and connected to fastening flange, arranged to be installed mainly inside process channel, within which chamber magnet and coil are arranged and through which chamber the flow channel passes, the frame installable such that flow channel is positioned inside process channel.