University of Minnesota

Siemens Healthcare Gmbh

Other

Siemens Healthineers Ag

National Institutes of Health (nih)

Kamil Ugurbil

Gregor Adriany

Michael G Garwood

J Thomas Vaughan, Jr

Pierre-Francois Van De Moortele

Dingxin Wang

Lance DelaBarre

Xiufeng Li

Steen Moeller

Carl J Snyder

Gregory John Metzger

Can E Akgun

Xiaoping Wu

Wei Chen

Jinfeng Tian

Edward Auerbach

John Strupp

Peter M Andersen

Haiying Liu

John Thomas Vaughan

Vibhas S Deshpande

Anand Gopinath

Heather Diane Orser

Essa Yacoub

Sebastian Schmitter

David A Feinberg

Patrick Bolan

Peter M Anderson

Shalom Michaeli

J Thomas Vaughan

Dennis J Sorce

Christopher C Olson

Russell L Lagore

Xiaodong Ma

Chris E Olson

Jerahmie Radder

Myung Kyun Woo

Xiaoliang Zhang

William Voje

Johannes Ritter

Gregor Adiany

Peter Andersen

Jr J Thomas Vaughan

Lance Delabarre

Chris Olson

Magnetic resonance images with improved image quality consistent with those obtained using parallel radio frequency ('RF') transmission (“pTx”) techniques are generated from data acquired using single transmission hardware (e.g., single channel RF transmission). A deep-learning framework is used to train a deep neural network to convert images obtained with single transmission into pTx-like images. The pTx-like images have reduced signal variations and dropouts that may otherwise be attributable to B1+ inhomogeneities.

Parallel transmission magnetic resonance imaging with a single transmission channel RF coil using deep learning

A method for generating a perfusion weighted image using arterial spin labeling (ASL) with segmented acquisitions includes dividing an anatomical area of interest into a plurality of slices and performing a multi-band (MB) echo planar imaging (EPI) acquisition process using a magnetic resonance imaging (MRI) system to acquire a control image dataset representative of the plurality of slices using a central-to-peripheral or peripheral-to-central slice acquisition order. An ASL preparation process is performed using the MRI system to magnetically label protons in arterial blood water in an area upstream from the anatomical area of interest. Following a post-labeling delay time period, the MB EPI acquisition process is performed to a labeled image dataset corresponding to the slices using the central-to-peripheral or peripheral-to-central slice acquisition order. A perfusion weighted image of the anatomical area is generated by subtracting the labeled image dataset from the control image dataset.

Slice ordering for MB-EPI ASL imaging

An antenna apparatus for a radio frequency (RF) coil to transmit signals to and to receive signal from a subject in a magnetic resonance imaging (MRI) system includes a distal surface facing away from the subject, a proximal surface facing towards the subject, a high permittivity material (HPM) having a shape, and an antenna coupled to the HPM and positioned on the proximal surface such that the antenna is positioned between the HPM and the subject.

Antenna apparatus including high permittivity materials (HPM) for radio frequency (RF) coils

A method for designing one or more multichannel, multiband radio frequency ('RF') pulses for use with a magnetic resonance imaging ('MRI') system is provided. The method includes determining a number of RF amplitude modulations and a number of RF phase modulations for each channel in a multichannel RF coil by minimizing an objective function that includes a complex-valued vector. The objective function also contains a system matrix that accounts for both a spatial sensitivity profile of each channel in the multichannel RF coil and a magnetic field map for each excitation band in the multiband RF pulse.

Multiband RF/MRI pulse design for multichannel transmitter

Embodiments can provide a method for multi-banded RF-pulse enhanced magnetization imaging, the method comprising determining, by a processor, a frequency offset against a central frequency by specifying an offset frequency for one or more RF coils close to a frequency peak of mobile water; and simultaneously applying, by one or more RF coils, one or more bands of Gaussian RF pulses around the central frequency to a patient from a medical imaging device; wherein the one or more bands of Gaussian RF pulses are symmetrically applied having a distance from the central frequency equal to the frequency offset.

Multi-banded RF-pulse enhanced magnetization imaging

Systems and methods for designing and/or using radio frequency ('RF') pulses for in-vivo MRI applications, where the RF pulses are robust against errors due to physiological motion of organs during the respiratory cycle. For example, RF pulses are designed based on multi-channel B1+ maps correlated to different positions of the respiratory cycle.

Systems and methods for designing magnetic resonance imaging radio frequency pulses that are robust against physiological motion errors

A magnetic resonance system is disclosed. The system includes a transceiver having a multichannel receiver and a multichannel transmitter, where each channel of the transmitter is configured for independent selection of frequency, phase, time, space, and magnitude, and each channel of the receiver is configured for independent selection of space, time, frequency, phase and gain. The system also includes a magnetic resonance coil having a plurality of current elements, with each element coupled in one to one relation with a channel of the receiver and a channel of the transmitter. The system further includes a processor coupled to the transceiver, such that the processor is configured to execute instructions to control a current in each element and to perform a non-linear algorithm to shim the coil.

High field magnetic resonance

A magnetic resonance method and system are provided for providing improved multi-band (MB) magnetic resonance imaging. The adaptive MB imaging can be achieved by providing one or more modified multi-band excitation pulse sequences that include at least either one nullified 'dummy' slice within a slab that is not excited simultaneously with the other slices during a single multislice acquisition sequence, or one excitation slice group that utilizes a non-uniform slice spacing between simultaneously excited slices. Adaptive GRAPPA or slice-GRAPPA kernel sizes can also be used during image reconstruction to improve speed without excessive point spread blurring or MB reconstruction failure. A total leakage factor (TLF) can also be determined based on test images using modified MB excitation sequences, and used to improve the adaptive MB procedure.

Apparatus and method for multi-band MR imaging

A computer-implemented method for performing multi-band slice accelerated imaging includes performing a low-resolution fast multi-dimensional reference scan to obtain a coil sensitivity map. A multiband imaging scan is performed to acquire a plurality of k-space lines representative of an anatomical area of interest. A multi-band signal corresponding to the plurality of k-space lines is separated into a plurality of image slices using a parallel imaging reconstruction technique and the coil sensitivity map.

Multiband slice accelerated imaging with balanced slice-selective gradients

A method for acquiring image data from a plurality of slice locations in a subject with a magnetic resonance imaging (MRI) system is provided. The method includes directing the MRI system to perform a pulse sequence that includes performing a contrast preparation module configured to generate contrast-encoded longitudinal magnetization and an image encoding module configured to acquire image data from multiple slice locations substantially simultaneously. The contrast preparation module generally includes tipping longitudinal magnetization into the transverse plane to produce transverse magnetization, generating contrast-prepared transverse magnetization by establishing an image contrast in the transverse magnetization, and tipping the contrast-prepared magnetization back along the longitudinal axis to produce the contrast-encoded longitudinal magnetization.

Method for rapid whole brain magnetic resonance imaging with contrast preparation

A method for generating a perfusion weighted image using ASL with segmented acquisitions includes dividing an anatomical area of interest into slices and performing an EPI acquisition process using an MRI system to acquire a control image dataset representative of the slices. An ASL preparation process is performed using the MRI system to magnetically label protons in arterial blood water upstream from the anatomical area of interest. Following a first time period, a multi-band EPI acquisition process is performed using the MRI system to acquire a first labeled image dataset representative of a first subset of the slices. Following a second time period, another multi-band EPI acquisition process is performed using the MRI system to acquire a second labeled image dataset representative of a second subset of the slices. A perfusion weighted image is generated by subtracting the first and second labeled image dataset from the control image dataset.

Time efficient ASL imaging with segmented multiband acquisition

A method for iteratively calibrating a reconstruction kernel for use in accelerated magnetic resonance imaging (MRI) is provided. An MRI system is used to acquire k-space data from multiple slice locations following the application of a multiband radio frequency (RF) excitation pulse. An initial reconstruction kernel is generated from the acquired k-space data, and this initial reconstruction kernel is used to produce an initial image for each of the multiple slice locations by applying the initial reconstruction kernel to the acquired k-space data. The average phase of each slice location is then calculated from these images, and used to shift the phase values of the subsequently acquired k-space data. From the phase-shifted k-space data, an updated reconstruction kernel is then generated. This process is repeated iteratively until a stopping criterion is satisfied.

System and method for iteratively calibrated reconstruction kernel for accelerated magnetic resonance imaging

A system and method for producing images depicting a plurality of slice locations in a subject using a magnetic resonance imaging ('MRI'} system is provided. In particular, the system and method utilize time-shifted multiband radio frequency ('RF'} pulses to lower peak voltage and peak power requirements when using conventional multiband RF pulses. A time-shifted multiband RF pulse includes at least two component RF pulses, which may be single-band or multiband pulses. The component RF pulses are designed such that they do not have temporal footprints that completely overlap; although, they may have temporal foot-prints that partially overlap or do not overlap at all. The MRI system is used to acquire magnetic resonance signals formed in response to a time-shifted multiband RF pulse and, from these acquired signals, images depicting each of the plurality of slice locations in the subject are reconstructed.

System and method for reducing radio frequency peak voltage and power requirements in magnetic resonance imaging using time-shifted multiband radio frequency pulses

A method is provided for substantially simultaneously manipulating spins in a plurality of slice locations using a magnetic resonance imaging ('MRI') system that includes a radio frequency ('RF') coil array composed of a plurality of RF coil elements, and in which power deposition, which may be measured as specific absorption rate (&#x201c;SAR&#x201d;), is reduce A plurality of slice locations to be substantially simultaneously manipulated with the MRI system are selected, and an RF transmission map (Bmap) is provided for each of the plurality of RF coil elements. A subset of slice locations to be manipulated by each of the RF coil elements is then selected using the provided RF transmission maps. Using the selected subsets of slice locations, an RF pulse to be transmitted by each of the RF coil elements is designed. The designed RF pulses are then substantially simultaneously transmitted by the MRI system to substantially simultaneously manipulate spins in each o the plurality of slice locations.

Method for reducing power deposition in magnetic resonance imaging using multiband pulses and multichannel transmission

Disclosed are methods and systems for carrying out super-multiplexed magnetic resonance imaging that entwines techniques previously used individually and independently of each other in Simultaneous Echo (or Imaging) Refocusing (SER or SIR) and Multi-Band (MB) excitation, in a single pulse sequence that provides a multiplication rather than summation of desirable effects while suppressing undesirable effects of each of the techniques that previously were used independently.

Multiplicative increase in MRI data acquisition with multi-band RF excitation pulses in a simultaneous image refocusing pulse sequence

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Minneapolis, MN, United States of America

Kamil Ugurbil