Mayo Foundation for Medical Education and Research

General Electric Company

Duke University

Other

Ge Medical Systems Global Technology Company, LLC

Stephen J Riederer

David G Kruger

Clifton R Haider

Phillip J Rossman

Gary S Keyes

Sean B Fain

Jason Andrew Polzin

Josef P Debbins

Ananth J Madhuranthakam

Barry N Stone

Houchun H Hu

James N Lee

Reed F Busse

Norbert G Campeau

Norbert Joseph Pelc

Christopher Judson Hardy

Robert David Darrow

Richard L Ehman

Frank A DiBianca

Thomas W Lambert

Clifford R Jack, Jr

William H Wesbey

Heidi A Ward

Philip J Rossman

Paul T Weavers

Soudabeh Kargar

Roger C Grimm

Eric G Stinson

Glenn S Slavin

Ek Tsoon Tan

Alan H Wilman

Edmund R Steinike

Daivd G Kruger

Gerald A Jensen

Ronald C Wright

Farhad Farzaneh

Casey P Johnson

Hope W Korin

Eric A Borisch

Anna E Bampton

Yu L Liu

The present disclosure provides systems and methods for measuring a concentration of a contrast agent using magnetic resonance imaging (MRI). The method includes acquiring pre- and post-contrast data from a volume of a subject, where the pre-contrast data is acquired before a contrast agent is administered and the post-contrast data is acquired after the contrast agent is administered. Pre- and post-contrast resonance frequency maps are then computed, where the pre-contrast frequency map is based on one or more pre-contrast resonance frequency values, and the post-contrast resonance frequency map is based on one or more post-contrast resonance frequency values. The pre- and post-contrast frequency maps are then used to generate a resonance frequency change map that is subsequently used to generate a contrast agent concentration map that indicates a concentration of the contrast agent that was present at each voxel in the volume at the second time.

Methods for determining contrast agent concentration using magnetic resonance imaging

Systems and methods for generating a three-dimensional image of an object from multiple two-dimensional images acquired using a magnetic resonance imaging ('MRI') system are provided. The three-dimensional image has high spatial resolution in all three spatial dimensions. The multiple two-dimensional images can be acquired in one or more orientations (e.g., axial, coronal, sagittal, oblique). The in-plane resolution of these images can be several times finer than the through-plane resolution (i.e., the slice thickness). The images are Fourier transformed along their respective slice orientation direction and processed using the slice profile to generate a Fourier representation of the three-dimensional image with the target spatial resolution. Inverse Fourier transforming this Fourier representation generates the desired three-dimensional image.

Synthetic three-dimensional magnetic resonance imaging

A method of producing a series of vasculature images over an extended field of view (FOV) larger than an FOV of an MRI system includes acquiring initial time-resolved image data from the vasculature and, during the acquiring process, reconstructing, in substantially real-time, a series of three-dimensional (3D) tracking images of the initial portion of the vasculature illustrating a current position of a contrast bolus in the vasculature as the contrast bolus passes through the initial portion of the vasculature. Based on a current position of the contrast bolus, the subject is moved to a subsequent imaging station to acquire subsequent time-resolved image data and reconstruct subsequent 3D tracking images of subsequent portions of the vasculature. This process is repeated and then an image is assembled that extends over the extended FOV using the initial time-resolved image data and the subsequent time-resolved image data.

System and method for imbedded, high-spatial resolution, fluoroscopic tracking of multi-station, contrast-enhanced magnetic resonance angiography

A system and method for performing parallel magnetic resonance angiography includes controlling operation of a magnetic gradient system and an RF system to perform a calibration data pulse sequence to begin acquiring calibration data for use in a parallel imaging reconstruction process after receiving an indication that the subject has received a dose of a contrast agent. The acquisition of the calibration data is discontinued before the contrast agent reaches a peak concentration within a region of interest (ROI) of the subject and operation of the magnetic gradient system and RF system is controlled to perform an imaging pulse sequence in accordance with a parallel imaging acquisition to begin acquiring image data from the ROI. The image data is reconstructed into an image of the ROI using the calibration data.

System and method for controlling calibration and delay phases of parallel, contrast-enhanced magnetic resonance imaging

A system and method are provided for producing a magnetic resonance image of a subject with a magnetic resonance imaging (MRI) system. The method includes acquiring k-space image data from a subject arranged in an MRI system by performing a pulse sequence. To perform the pulse sequence the MRI system divides k-space into a plurality of radially-extending sectors extending along a radial direction away from an origin of k-space. The plurality of radially-extending sectors include a width transverse to the radial direction that is defined by a vane angle chosen to be greater than a floating point precision of the trigonometric functions that define the radially-extending sectors. The MRI system acquires imaging data from at least the radially-extending sectors to undersample the periphery of k-space by only sampling k-space within the plurality of radial sectors and reconstructs an image of the subject using the imaging data.

System and method for random cartesian acquisition with projection reconstruction-like sampling

A method for three-dimensional parallel magnetic resonance imaging (MRI) using an MRI system is provided. The method includes determining in-plane acceleration factors that optimize a selected criterion, such as an image quality criterion defined by maximal noise amplification in a reconstructed image. The estimated in-plane acceleration factors are used to establish a k-space sampling pattern, which is used to acquire k-space data. An image is reconstructed from the acquired k-space data using a parallel image reconstruction technique.

System and method for parallel magnetic resonance imaging with optimally selected in-plane acceleration

A method for producing a time-series of images of a subject with a magnetic resonance imaging (MRI) system is provided. The MRI system is used to acquire a time-series undersampled k-space data set, in which a selected number of k-space data subsets in the time-series data set includes both image data and calibration data. Moreover, the calibration data in each of these selected number of k-space data subsets includes a portion of a desired total amount of calibration data. For example, each of these selected number of k-space data subsets include calibration data that is acquired by sampling a different partition of a calibration data sampling pattern. A time-series of images of the subject is then produced by reconstructing images of the subject from the acquired time-series of undersampled k-space data sets. These images are substantially free of undersampling artifacts.

Method for self-calibrated parallel magnetic resonance image reconstruction

A method for performing magnetic resonance angiography and perfusion imaging using the same pulse sequence is provided. Time-resolved image data is acquired as a contrast agent passes through a subject. This image data is acquired by sampling Cartesian points in k-space that are contained within either a central region of k-space, or one of a plurality of different sets of radial sectors extending outwards from the central region. The image data is combined to form individual image frame data sets that are then reconstructed to produce a time series of image frames. From this time series, MR angiograms and perfusion maps are produced. With the added acquisition of calibration data, T1 relaxation parameters are estimated and quantitative perfusion maps produced.

System and method for combined time-resolved magnetic resonance angiography and perfusion imaging

A system and method for creating at least one angiographic image using a magnetic resonance imaging (MRI) system includes acquiring, with the MRI system and using parallel imaging techniques, a pre-contrast image data set and a post-contrast image data set of a portion of a subject having a vascular structure extending therethrough and subtracting the pre-contrast and the post-contrast image data set to generate a difference angiogram data set. The method includes reconstructing the difference angiogram data set into at least one aliased angiogram, creating a region of interest (ROI) mask from an image of the portion of the subject, and indicating a masking border surrounding the vascular structure and substantially excluding tissues surrounding the vascular structure. The method then includes de-aliasing the at least one aliased angiogram using the ROI mask to create an angiogram of the portion of the subject.

System and method for improved accelerated magnetic resonance imaging using ROI masking

The present invention provides an MRI system for imaging of a subject over extended field-of-view (FOV) that employs both accelerated data acquisition, which is employed while the subject is stationary, and traditional data acquisition, which is employed while the subject is moved through the MRI system. This approach provides improved spatial resolution and time efficiency compared to traditional extended FOV imaging techniques.

System and method for moving table MRI

An improved self-calibration method for accelerated magnetic resonance imaging (MRI) using inversion recovery pulse sequences allows calibration data for determining coil sensitivity profiles to be acquired by employing a calibration pulse sequence within the delay time of an inversion recovery pulse sequence. The calibration pulse sequence includes a constrained number of calibration pulses having small flip angles so that acceptable longitudinal magnetization recovery is provided.

System and method for embedded self-calibration within an inversion recovery pulse sequence

An MRI system produces a three-dimensional image by acquiring NMR signals that fully sample a central region of k-space and partially sample peripheral k-space as a set of asymmetric radial sectors. The NMR signals are acquired with a plurality of receive channels and coils. An image is reconstructed using a homodyne reconstruction combined with SENSE processing.

MRI acquisition using 2D sense and partial fourier pace sampling

The present invention is a coil array for an MRI system that is designed to improve 2D accelerated imaging of an object having significantly different fields of view in two phase-encoding directions. This is achieved by having a first set of coil elements whose sizes are tuned to optimize acceleration along a first phase-encoding direction and a second set of coil elements whose sizes are tuned to optimize acceleration along a second-phase encoding direction. Images acquired in accordance with the present invention exhibit improved signal to noise ratio at a given acceleration factor when compared to images acquired using a traditional MR coil array.

Method and apparatus for improving 2D acceleration in MRI using a new coil array design

An MRI system produces a three-dimensional image by acquiring NMR signals that fully sample a central region of k-space and partially sample peripheral region of k-space. Specifically, k-space is arranged as a three-dimensional (3D) Cartesian grid of points that is divided into a central region of k-space and a peripheral region of k-space. Points are selected in k-space within a plurality of radial vanes that extend radially outward from the central region of k-space through the peripheral region of k-space as viewed in a plane sampled by two phase encoding gradients to create a plurality of gaps between the radial vanes that is substantially a factor of N times greater in area than the radial vanes. Using an MRI system having arrays of RF receiver coils, NMR signals are acquired from a subject to fully sample the central region of the 3D k-space and undersample the peripheral region of k-space by only sampling k-space within the plurality of radial vanes. An image of the subject is reconstructed using the acquired NMR signals.

MRI acquisition using sense and highly undersampled fourier space sampling

MRA data is acquired from an extended field of view by translating the patient through the bore of the MRI system as three-dimensional MRA data sets are acquired and time-resolved images reconstructed. The leading edge of a contrast bolus can be tracked in these images and parameters such as bolus velocity and bolus arrival time can be calculated to provide functional information in addition to anatomical information. Temporal resolution is improved by undersampling peripheral k-space and sampling the center of k-space at a higher temporal rate.

Method for acquiring time-resolved MR images using continuous table motion

Growing community of inventors

Rochester, MN, United States of America

Stephen J Riederer