公开(公告)号：US20240241201A1

公开(公告)日：2024-07-18

申请号：US18559316

申请日：2022-05-09

申请人： The U.S.A, as represented by the Secretary, Department of Health and Human Services

发明人： Bu S. Park

IPC分类号： G01R33/54 ,  G01R33/561 ,  G01R33/565

CPC分类号： G01R33/543 ,  G01R33/5612 ,  G01R33/5659

摘要： A measurement volume is divided into multiple regions of interest (ROIs) and RF shimming parameters are independently selected for each of the ROIs. The ROIs have dimensions based on an RF wavelength in a specimen (i.e., based on RF frequency and specimen dielectric constant) and are selected to reduce wavelength-based nonuniformity in specimen excitation. For a multi-segment RF coil having segments situated about a cylindrical surface, ROI shapes include cylinders and cylindrical shells aligned along a coil axis.

公开(公告)号：US20240183918A1

公开(公告)日：2024-06-06

申请号：US18277735

申请日：2022-03-11

申请人： COMMISSARIAT A L’ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

发明人： Vincent GRAS ,  Franck MAUCONDUIT ,  Nicolas BOULANT

IPC分类号： G01R33/483 ,  G01R33/48 ,  G01R33/561 ,  G01R33/565

CPC分类号： G01R33/4835 ,  G01R33/4826 ,  G01R33/5612 ,  G01R33/5659

摘要： A method for determining a global and regular parameterization for a family of spin-excitation pulse sequences in magnetic resonance imaging, with each pulse sequence of the family being a multi-spoke type sequence suitable for selectively exciting nuclear spins in a slice of a volume of interest of a body immersed in a static magnetic field and comprising radiofrequency pulses at a Larmor frequency of the nuclear spins alternated with magnetic gradient pulses. The global parameterization minimizes a function representing a mean deviation from a setpoint of the excitation of the nuclear spins, with the mean being computed for the volume of interest and for all the possible orientations and positions of the slices. It allows a selective excitation sequence to be simply designed for a slice with a random orientation and position.

公开(公告)号：US10073154B2

公开(公告)日：2018-09-11

申请号：US14774175

申请日：2014-03-13

申请人： KONINKLIJKE PHILIPS N.V.

发明人： Christoph Leussler ,  Daniel Wirtz

IPC分类号： G01R33/34 ,  G01R33/28 ,  G01R33/3415 ,  G01R33/36 ,  G01R33/561

CPC分类号： G01R33/3415 ,  G01R33/288 ,  G01R33/34053 ,  G01R33/34084 ,  G01R33/36 ,  G01R33/3692 ,  G01R33/5612

摘要： The invention provides for a multi-element transmit coil (100) for a magnetic resonance imaging system (300). The multi-element transmit coil comprises multiple surface coil elements (102) with a coil circuit (104) that has an integrated a radio-frequency sensor (106, 604, 704, 804). The multi-element transmit coil further comprises a power monitoring unit (108) with an analog-to-digital converter (808). The power monitoring unit comprises a processor connected to each analog to digital converter that is operable for receiving a radio-frequency measurement for generating specific absorption rate data (348) for each of the multiple surface coil elements. The multi-element transmit coil further comprises an optical data transmission system (110) connected to the processor. The optical data transmission system is operable for connecting to a magnetic resonance imaging system controller (312, 330). The optical data transmission system is operable for transferring the specific absorption rate data to the magnetic resonance imaging system controller.

公开(公告)号：US20180246178A1

公开(公告)日：2018-08-30

申请号：US15573918

申请日：2016-05-16

申请人： OHIO STATE INNOVATION FOUNDATION

发明人： Jinghua WANG ,  Yu DING

IPC分类号： G01R33/24 ,  G01V3/14 ,  G01R33/565 ,  A61B5/055 ,  G01R33/561

CPC分类号： G01R33/246 ,  A61B5/055 ,  G01R33/5612 ,  G01R33/5659 ,  G01V3/14

摘要： Systems and methods for estimating complex transmit field B1+ a transmit coil of a magnetic resonance imaging (MRI) system in both k-space and image domains are described herein. Estimating complex RF field B1+ in the k-space domain includes acquiring complex data in a k-space domain, estimating a complex B1+ map in the k-space domain of a transmit coil and storing the complex B1+ map. The complex B1+ map can be estimated based on the complex images. Estimating complex transmit field B1+ in the image domain includes acquiring at least two complex images in a k-space domain, transforming the complex images into an image domain, estimating a complex B1+ map in the image domain of a transmit coil, and storing the complex B1+ map.

公开(公告)号：US09964619B2

公开(公告)日：2018-05-08

申请号：US14627207

申请日：2015-02-20

申请人： Siemens Aktiengesellschaft

发明人： Rainer Schneider

IPC分类号： G01R33/54 ,  G01R33/34 ,  G01R33/44 ,  G01R33/48 ,  G01R33/483 ,  G01R33/24 ,  G01R33/56 ,  G01R33/561

CPC分类号： G01R33/543 ,  G01R33/243 ,  G01R33/246 ,  G01R33/34092 ,  G01R33/443 ,  G01R33/4818 ,  G01R33/482 ,  G01R33/4833 ,  G01R33/546 ,  G01R33/5608 ,  G01R33/5612

摘要： In a method and magnetic resonance apparatus for determination of radio-frequency pulses, a time-parallel transmission of a radio-frequency pulse influences the transverse magnetization of an object under examination in a specified spatial region. The spatial region is depicted as a vector and approximated by decomposition into a finite number of weighted basis functions of the decomposition. As a result, the length of the approximated vector is less than the length of the original vector. The radio-frequency pulse is determined as a function of the approximated vector. This method can be used to determine a multichannel RF pulse.

公开(公告)号：US20180120398A1

公开(公告)日：2018-05-03

申请号：US15800831

申请日：2017-11-01

申请人： The Board of Trustees of the Leland Stanford Junior University

发明人： Mihir Pendse ,  Brian Rutt

IPC分类号： G01R33/483 ,  G01R33/28

CPC分类号： G01R33/4835 ,  G01R33/288 ,  G01R33/5612 ,  G01R33/5659

摘要： Obtaining minimum duration parallel transmit pulses for simultaneous multislice imaging that includes minimizing specific absorption rate hotspots, using an IMPULSE pTx optimization method to determine multiple spoke locations and multiple channel weights for multiple slices while enforcing a specified flip angle inhomogeneity tolerance over the multiple slices when excited, applying a control algorithm to conform a simultaneous multislice (SMS) pulse to the excited multiple slices to minimize a cost function having terms corresponding to an excitation accuracy and a pulse power, where a regularization term in the cost function is configured by the control algorithm for excitation accuracy while limiting a peak pulse power, and applying a time-optimal variable rate selective excitation (VERSE) to enforce a peak power constraint with a minimum pulse duration by reshaping a RF waveform and a gradient waveform without altering an excitation profile if the peak power limit on a channel is exceeded.

公开(公告)号：US20180106878A1

公开(公告)日：2018-04-19

申请号：US15820718

申请日：2017-11-22

申请人： TOSHIBA MEDICAL SYSTEMS CORPORATION

发明人： Kazuyuki SOEJIMA ,  Haruki NAKAMURA ,  Takuma KAWAI ,  Kazuya OKAMOTO

IPC分类号： G01R33/54 ,  G01R33/36 ,  A61B5/055 ,  A61B5/00 ,  G01R33/561

CPC分类号： G01R33/543 ,  A61B5/0037 ,  A61B5/055 ,  G01R33/36 ,  G01R33/3607 ,  G01R33/5612

摘要： According to one embodiment, a magnetic resonance imaging apparatus provided with a plurality of transmission channels includes a signal processing unit and a control unit. The signal processing unit acquires a radio frequency magnetic field emitted from each of the plurality of transmission channels through a receiver coil mounted on an object and measure a phase of the radio frequency magnetic field. The control unit determines a phase difference between the plurality of transmission channels based on the phase of the radio frequency magnetic field of each of the plurality of transmission channels measured by the signal processing unit. The control unit controls a phase of a radio frequency pulse inputted to each of the plurality of transmission channels, based on the phase difference.

公开(公告)号：US09726744B2

公开(公告)日：2017-08-08

申请号：US14241515

申请日：2012-07-27

申请人： Yukio Kaneko ,  Yoshihisa Soutome ,  Yoshitaka Bito ,  Hiroyuki Takeuchi ,  Tetsuhiko Takahashi ,  Hideta Habara ,  Yosuke Otake

发明人： Yukio Kaneko ,  Yoshihisa Soutome ,  Yoshitaka Bito ,  Hiroyuki Takeuchi ,  Tetsuhiko Takahashi ,  Hideta Habara ,  Yosuke Otake

IPC分类号： G01R33/565 ,  G01R33/24 ,  A61B5/055 ,  G01R33/483 ,  G01R33/561

CPC分类号： G01R33/5659 ,  A61B5/055 ,  G01R33/246 ,  G01R33/4835 ,  G01R33/5612

摘要： Systems and methods for magnetic resonance imaging, including adjusting spatial distribution of a rotating magnetic field. By minimizing imaging time, the B1 nonuniformity reducing effect of RF shimming is maximized for an imaging section of an arbitrary axis direction and an arbitrary position. B1 distributions are measured for only several sections of one predetermined direction, and a radio frequency magnetic field condition that maximizes the B1 non-uniformity reducing effect for an imaging section of an arbitrary direction and an arbitrary position is calculated from the B1 distribution data.

公开(公告)号：US09689945B2

公开(公告)日：2017-06-27

申请号：US13816305

申请日：2011-08-15

申请人： Kay Nehrke ,  Peter Boernert

发明人： Kay Nehrke ,  Peter Boernert

IPC分类号： G01V3/00 ,  G01R33/54 ,  G01R33/561 ,  G01R33/565

CPC分类号： G01R33/543 ,  G01R33/5612 ,  G01R33/5659

摘要： A virtual coil emulation method is used in a magnetic resonance imaging scan for acquiring a magnetic resonance image of an object (10). The scan is performed by an MR system (1) using a physical coil arrangement (9; 11; 12; 13) including a set of individual transmit coils. The coils are adapted for transmission of a desired RF transmit field to the object (10) for magnetic resonance spin excitation of the object (10). Each coil is associated with a physical transmit channel. The RF transmit field corresponds to a virtual arrangement of two or more of the coils. Virtual transmit channel properties include virtual transmit channel weights are assigned to the RF transmit field which describe the virtual complex RF field amplitudes with respect to each individual coil of the virtual coil arrangement to be applied to the physical coils (9; 11; 12; 13) for generating the RF transmit field.

公开(公告)号：US09625551B2

公开(公告)日：2017-04-18

申请号：US13863530

申请日：2013-04-16

申请人： Ali Caglar Ozen ,  Ergin Atalar

发明人： Ali Caglar Ozen ,  Ergin Atalar

IPC分类号： G01V3/00 ,  G01R33/54 ,  G01R33/36 ,  G01R33/48 ,  G01R33/561

CPC分类号： G01R33/543 ,  G01R33/3657 ,  G01R33/4816 ,  G01R33/4824 ,  G01R33/5612

摘要： In magnetic resonance data acquisition, decoupling between the transmit and receive coils is achieved by using a transmit array system wherein induced currents from the transmit coils cancel each other, resulting in a total of zero current in the receive coil. Forward and reversed polarized transmit coil pairs are set to cancel the individual currents of each other, or of a receive coil. Linearly polarized fields can also be used to effect the decoupling. The decoupling allows the magnetic resonance data acquisition system to be operated for concurrent excitation of the nuclear spins and reception of the resulting magnetic resonance signals.