Patents by Inventor Lawrence L. Wald

Lawrence L. Wald has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 10436866
    Abstract: Systems and methods for simultaneous multislice (“SMS”} magnetic resonance imaging (“MRI”}, in which a random blip gradient encoding scheme is utilized to impart a different phase to each of a plurality of different slice locations. Because of the random blip gradient encoding, the amount of the imparted phase is randomized for each phase encoding step in a Cartesian k-space trajectory. This data acquisition strategy leads to incoherent aliasing artifacts across the simultaneously excited slices. Images of the individual slices can be reconstructed using a compressed sensing framework.
    Type: Grant
    Filed: January 30, 2015
    Date of Patent: October 8, 2019
    Assignee: The General Hospital Corporation
    Inventors: Berkin Bilgic, Kawin Setsompop, Lawrence L. Wald
  • Patent number: 10429475
    Abstract: A method for maximizing the signal-to-noise ratio (“SNR”) in a combined image produced using a parallel magnetic resonance imaging (“MRI”) technique is provided. The image combination used in such techniques require an accurate estimate of the noise covariance. Typically, the thermal noise covariance matrix is used as this estimate; however, in several applications, including accelerated parallel imaging and functional MRI, the noise covariance across the coil channels differs substantially from the thermal noise covariance. By combining the individual channels with more accurate estimates of the channel noise covariance, SNR in the combined data is significantly increased. This improved combination employs a regularization of noise covariance on a per-voxel basis.
    Type: Grant
    Filed: March 12, 2014
    Date of Patent: October 1, 2019
    Assignee: The General Hospital Corporation
    Inventors: Jonathan R. Polimeni, Kawin Setsompop, Lawrence L. Wald
  • Patent number: 10408910
    Abstract: Systems and methods for estimating the actual k-space trajectory implemented when acquiring data with a magnetic resonance imaging (“MRI”) system while jointly reconstructing an image from that acquired data are described. An objective function that accounts for deviations between the actual k-space trajectory and a designed k-space trajectory while also accounting for the target image is optimized. To reduce the computational burden of the optimization, a reduced model for the parameters associated with the k-space trajectory deviation and the target image can be implemented.
    Type: Grant
    Filed: September 30, 2016
    Date of Patent: September 10, 2019
    Assignee: The General Hospital Corporation
    Inventors: Stephen Cauley, Kawin Setsompop, Lawrence L Wald
  • Patent number: 10359481
    Abstract: A portable magnetic resonance imaging (“MRI”) system that uses static magnetic field inhomogeneities in the main magnet for encoding the spatial location of nuclear spins is provided. Also provided is a spatial-encoding scheme for a low-field, low-power consumption, light-weight, and easily transportable MRI system. In general, the portable MRI system spatially encodes images using spatial inhomogeneities in the polarizing magnetic field rather than using gradient fields. Thus, an inhomogeneous static field is used to polarize, readout, and encode an image of the object. To provide spatial encoding, the magnet is rotated around the object to generate a number of differently encoded measurements. An image is then reconstructed by solving for the object most consistent with the data.
    Type: Grant
    Filed: October 22, 2012
    Date of Patent: July 23, 2019
    Assignee: The General Hospital Corporation
    Inventors: Lawrence L. Wald, Clarissa Zimmerman, Jason Stockmann
  • Patent number: 10345409
    Abstract: Systems and methods for controlling a magnetic resonance imaging (MRI) system to simultaneously excite multiple different slice locations. A multiband (MB) radio frequency (RF) pulse waveform is combined with an RF pulse waveform that results in periodic excitation of the slice locations, such as a power independent of a number of slices (PINS) RF pulse waveform. Before combination, the MB RF pulse waveform is preferably transformed to traverse the excitation k-space trajectory defined by a plurality of slice-encoding gradient blips. The combined RF pulse waveform is used to generate an RF excitation field generated while the plurality of slice-encoding gradient blips are played out. The portions of the combined RF pulse associated with the MB RF pulse are played out during the gradient blips, and the portions associated with the PINS RF pulse are played out between the gradient blips.
    Type: Grant
    Filed: January 30, 2015
    Date of Patent: July 9, 2019
    Assignee: The General Hospital Corporation
    Inventors: Cornelius Eichner, Lawrence L. Wald, Kawin Setsompop
  • Patent number: 10324149
    Abstract: Described here are systems and methods for using excited slice profiles to improve the point spread function (“PSF”) of super-resolution slices in SLIDER acquisitions while preserving all of the advantages of the SLIDER technique. The techniques described here may generally be referred to as “Generalized SLIDER” (“g-SLIDER”).
    Type: Grant
    Filed: October 5, 2016
    Date of Patent: June 18, 2019
    Assignee: The General Hospital Corporation
    Inventors: Kawin Setsompop, Jason Stockmann, Lawrence L Wald
  • Patent number: 10310031
    Abstract: Described here are a system and method for designing radio frequency (“RF”) pulses for parallel transmission (“pTx”) applications, and particularly pTx applications in magnetization transfer (“MT”) magnetic resonance imaging (“MRI”). The concept of “SAR hopping” is implemented using a constrained optimization problem that simultaneously designs multiple RF sub-pulses to maximize power deposition in a bound proton pool while also minimizing local SAR across multiple bound proton pool excitation frequencies. This results in the set of RF waveforms that yield the best excitation profiles for all pulses while ensuring that the local SAR of the average of all pulses is below the regulatory limit imposed by the FDA. Pulses are designed simultaneously while constraining local SAR, global SAR, and peak voltage, explicitly.
    Type: Grant
    Filed: November 3, 2016
    Date of Patent: June 4, 2019
    Assignee: The General Hospital Corporation
    Inventors: Bastien Guerin, Lawrence L Wald
  • Publication number: 20190128982
    Abstract: Described here are systems and methods for performing magnetic resonance imaging (“MRI”) using radio frequency (“RF”) phase gradients to provide spatial encoding of magnetic resonance signals rather than the conventional magnetic field gradients. Particularly, the systems and methods described here implement swept RF pulses (e.g., wideband, uniform rate, and smooth transition (“WURST”) RF pulses) and a quadratic phase correction to enable RF phase gradient encoding in inhomogeneous background (B0) magnetic fields.
    Type: Application
    Filed: April 11, 2017
    Publication date: May 2, 2019
    Applicant: The General Hospital Corporation
    Inventors: Lawrence L. WALD, Clarissa Z. COOLEY, Jason STOCKMANN, Bastien GUERIN, Matthew ROSEN
  • Publication number: 20190035119
    Abstract: Described here are systems and methods for retrospectively estimating and correcting for rigid-body motion by using a joint optimization technique to jointly solve for motion parameters and the underlying image. This method is implemented for magnetic resonance imaging (“MRI”), but can also be adapted for other imaging modalities.
    Type: Application
    Filed: January 30, 2017
    Publication date: January 31, 2019
    Inventors: Stephen Cauley, Melissa Haskell, Lawrence L. Wald
  • Patent number: 10139465
    Abstract: A method for imaging a subject with a magnetic resonance imaging (MRI) system using controlled aliasing is provided. A radio frequency (RF) excitation field is applied to excite the spins in a volume-of-interest that may include multiple slice locations. Using the MRI system, a readout magnetic field gradient is established following the application of the RF excitation field to form echo signals. These echo signal receive a differential encoding by way of establishing, while the readout gradient is established, alternating magnetic field gradients along two directions, such as the partition-encoding and phase-encoding directions. Image data is acquired from the formed echo signals and images of the subject are reconstructed from the acquired image data.
    Type: Grant
    Filed: February 9, 2015
    Date of Patent: November 27, 2018
    Assignee: The General Hospital Corporation
    Inventors: Kawin Setsompop, Lawrence L. Wald
  • Patent number: 9983282
    Abstract: Spin-lock T1?-weighted images of a subject are acquired and processed to produce an image that is indicative of bioelectromagnetic activity in the subject. A spin-lock RF field B1? is produced such that the Larmor frequency in the rotating frame corresponds to the expected frequency of the bioelectromagnetic activity. As a result, the magnetic field fluctuations generated by the bioelectromagnetic currents shorten the T1? of the surrounding tissue, creating a contrast mechanism that is seen as a reduced MR signal in the T1?-weighted image that is produced.
    Type: Grant
    Filed: November 21, 2007
    Date of Patent: May 29, 2018
    Assignee: The General Hospital Corporation
    Inventors: Lawrence L. Wald, Thomas Witzel, Bruce R. Rosen
  • Publication number: 20180100908
    Abstract: Systems and methods for simultaneously acquiring high-resolution images of a subject from multiple different slice locations using magnetic resonance imaging (“MRI”) are described. The present invention overcomes the aforementioned drawbacks by providing method for producing a plurality of images of a subject with a magnetic resonance imaging (“MRI”) system. A radio frequency (RF) excitation field is applied by the MRI system to a portion of a subject that includes a plurality of slice locations. First data are simultaneously acquired from each of the plurality of slice locations by the MRI system.
    Type: Application
    Filed: October 2, 2015
    Publication date: April 12, 2018
    Inventors: Kawin Setsompop, Berkin Bilgic, Lawrence L. Wald, Thomas Witzel
  • Patent number: 9910115
    Abstract: A portable magnetic resonance imaging (“MRI”) system that uses static magnetic field inhomogeneities in the main magnet for encoding the spatial location of nuclear spins is provided. Also provided is a spatial-encoding scheme for a low-field, low-power consumption, light-weight, and easily transportable MRI system. In general, the portable MRI system spatially encodes images using spatial inhomogeneities in the polarizing magnetic field rather than using gradient fields. Thus, an inhomogeneous static field is used to polarize, readout, and encode an image of the object. To provide spatial encoding, the magnet is rotated around the object to generate a number of differently encoded measurements. An image is then reconstructed by solving for the object most consistent with the data.
    Type: Grant
    Filed: December 6, 2013
    Date of Patent: March 6, 2018
    Assignee: The General Hospital Corporation
    Inventors: Lawrence L. Wald, Clarissa Zimmerman, Jason Stockman
  • Patent number: 9778338
    Abstract: A method for multi-slice magnetic resonance imaging, in which image data is acquired simultaneously from multiple slice locations using a radio frequency coil array, is provided. By way of example, a modified EPI pulse sequence is provided, and includes a series of magnetic gradient field “blips” that are applied along a slice-encoding direction contemporaneously with phase-encoding blips common to EPI sequences. The slice-encoding blips are designed such that phase accruals along the phase-encoding direction are substantially mitigated, while providing that signal information for each sequentially adjacent slice location is cumulatively shifted by a percentage of the imaging FOV. This percentage FOV shift in the image domain provides for more reliable separation of the aliased signal information using parallel image reconstruction methods such as SENSE.
    Type: Grant
    Filed: March 1, 2013
    Date of Patent: October 3, 2017
    Assignee: The General Hospital Corporation
    Inventors: Kawin Setsompop, Lawrence L. Wald
  • Patent number: 9778336
    Abstract: A system and method for medical imaging using a magnetic resonance imaging system includes performing a segmented echo planar imaging (EPI) pulse sequence. The pulse sequence includes performing multiple radio frequency (RF) excitation pulses designed to excite multiple imaging slices across the subject simultaneously. A gradient encoding scheme applied along the slice-encoding direction is implemented to impart controlled phase shifts to the different imaging slices. Additionally, the multiple RF excitation pulses can be designed to further control an overlap of imaging data acquired from adjacent slices of the multiple imaging slices based on a selected offset. The acquired imaging data is reconstructed using a parallel imaging reconstruction method that separates overlapped slices in the imaging data to provide a series of images with respective images for each of the multiple imaging slices across the subject.
    Type: Grant
    Filed: February 13, 2014
    Date of Patent: October 3, 2017
    Assignee: The General Hospital Corporation
    Inventors: Jonathan R Polimeni, Lawrence L Wald, Kawin Setsompop
  • Publication number: 20170123022
    Abstract: Described here are a system and method for designing radio frequency (“RF”) pulses for parallel transmission (“pTx”) applications, and particularly pTx applications in magnetization transfer (“MT”) magnetic resonance imaging (“MRI”). The concept of “SAR hopping” is implemented using a constrained optimization problem that simultaneously designs multiple RF sub-pulses to maximize power deposition in a bound proton pool while also minimizing local SAR across multiple bound proton pool excitation frequencies. This results in the set of RF waveforms that yield the best excitation profiles for all pulses while ensuring that the local SAR of the average of all pulses is below the regulatory limit imposed by the FDA. Pulses are designed simultaneously while constraining local SAR, global SAR, and peak voltage, explicitly.
    Type: Application
    Filed: November 3, 2016
    Publication date: May 4, 2017
    Inventors: Bastien Guerin, Lawrence L Wald
  • Publication number: 20170102442
    Abstract: Described here are systems and methods for using excited slice profiles to improve the point spread function (“PSF”) of super-resolution slices in SLIDER acquisitions while preserving all of the advantages of the SLIDER technique. The techniques described here may generally be referred to as “Generalized SLIDER” (“g-SLIDER”).
    Type: Application
    Filed: October 5, 2016
    Publication date: April 13, 2017
    Inventors: Kawin Setsompop, Jason Stockmann, Lawrence L. Wald
  • Publication number: 20170097403
    Abstract: Systems and methods for estimating the actual k-space trajectory implemented when acquiring data with a magnetic resonance imaging (“MRI”) system while jointly reconstructing an image from that acquired data are described. An objective function that accounts for deviations between the actual k-space trajectory and a designed k-space trajectory while also accounting for the target image is optimized. To reduce the computational burden of the optimization, a reduced model for the parameters associated with the k-space trajectory deviation and the target image can be implemented.
    Type: Application
    Filed: September 30, 2016
    Publication date: April 6, 2017
    Inventors: STEPHEN CAULEY, KAWIN SETSOMPOP, LAWRENCE L. WALD
  • Publication number: 20170074956
    Abstract: A system and method for performing parallel magnetic resonance imaging (pMRI) process using a low-field magnetic resonance imaging (IfMRI) system includes a substrate configured to follow a contour of a portion of a subject to be imaged by the IfMRI system using a pMRI process. A plurality of coils are coupled to the substrate. Each coil in the plurality of coils has a number of turns and an associated decoupling mechanism selected to operate the plurality of coils to effectuate the pMRI process using the IfMRI system.
    Type: Application
    Filed: March 13, 2015
    Publication date: March 16, 2017
    Inventors: Matthew S. Rosen, Lawrence L. Wald, Cristen LaPierre
  • Publication number: 20170010340
    Abstract: Systems and methods for controlling a magnetic resonance imaging (MRI) system to simultaneously excite multiple different slice locations. A multiband (MB) radio frequency (RF) pulse waveform is combined with an RF pulse waveform that results in periodic excitation of the slice locations, such as a power independent of a number of slices (PINS) RF pulse waveform. Before combination, the MB RF pulse waveform is preferably transformed to traverse the excitation k-space trajectory defined by a plurality of slice-encoding gradient blips. The combined RF pulse waveform is used to generate an RF excitation field generated while the plurality of slice-encoding gradient blips are played out. The portions of the combined RF pulse associated with the MB RF pulse are played out during the gradient blips, and the portions associated with the PINS RF pulse are played out between the gradient blips.
    Type: Application
    Filed: January 30, 2015
    Publication date: January 12, 2017
    Applicant: The General Hospital Corporation
    Inventors: Cornelius Eichner, Lawrence L. Wald, Kawin Setsompop