Elscint Ltd.

General Electric Company

Ge Medical Systems Global Technology Company, LLC

Ge Medical Systems

Yuval Zur

Daniel Rosenfeld

William Allyn Grissom

Noam Kaplan

Jingfei Ma

Daniel I Barnea

Saul Stokar

Shimon Panfil

Haim Rotem

Amir Ban

Shimon L Panfil

Dan Rosenfeld

Tomas Duby

A system and method for MR imaging is disclosed. The method causes an RF coil assembly and plurality of gradient coils to apply a fast spin echo (FSE) pulse sequence comprising a preparation segment and a plurality of refocusing segments. The FSE pulse sequence generates a pair of echoes is generated in each of the plurality of refocusing segments that comprises a first echo generated by magnetization pathways having an even number of phase inversions and a second echo generated by magnetization pathways having an even number of phase inversions. MR signals are acquired from the first echo and the second echo and an image of at least a portion of a subject of interest is reconstructed from the acquired MR signals.

System and method for focusing of high intensity focused ultrasound based on magnetic resonance&#x2014;acoustic radiation force imaging feedback

A system and method for focusing ultrasound into a target tissue is disclosed. The method calculates a pressure field for an array of transducer elements to generate an unaberrated pressure field matrix and causes the transducer elements to apply focused ultrasound to generate a respective aberrated pressure field at a focus location in a target tissue and surrounding volume. MR-ARFI images are acquired of the focus location and surrounding volume, a magnitude of the aberrated pressure field is measured that is generated by the applied focused ultrasound at respective focus locations in the target tissue and surrounding volume based on the MR-ARFI images, an aberration for the transducer elements is determined from the pressure field matrix and the MR-ARFI images of the focus location and the surrounding volume using a magnitude least-squares method, and a corrective phase/amplitude adjustment is applied to the transducer elements based on the determined aberrations.

Phase and magnitude correction is performed in two dimensions to reduce ghosting in single shot and multi-shot EPI scans. First, a phase/magnitude correction in the readout direction is carried out to reduce echo shifts and gradient waveform distortions. Then, a two dimensional phase/magnitude correction is performed to remove the remaining xy phase/magnitude errors.

Method and apparatus of MR imaging with two dimensional phase and magnitude correction

A system and method for MR based tracking of a tissue point includes a RF coil assembly configured to emit RF pulse sequences and a system control coupled to the RF coil assembly. The system control is programmed to cause the RF coil assembly to emit a first RF pulse comprising a first pair of two-dimensional (2D) spatially selective beams, each of the beams being directed to a respective tagging location in the subject of interest and wherein the tagging locations are equidistant from a pre-determined point-of-interest. The system control is further programmed to acquire a first series of MR images from a subject of interest, identify the first pair of 2D spatially selective beams in each MR image in the first series of MR images, and track a position of the point-of-interest based on the identified 2D spatially selective beams in the first series of MR images.

System and method for tissue point tracking using magnetic resonance imaging

Artifacts in MR images caused by signals emanating from outside the design spherical volume (DSV) of the system are suppressed using customized spatial saturation pulse sequences interleaved with imaging pulse sequences. The spatial saturation pulse sequences are each customized to a specific region and are stored in a library for selective use when needed to suppress artifact producing signals emanating from specific regions outside the DSV.

Customized spatial saturation pulse sequence for suppression of artifacts in MR images

Magnetic resonance imaging system

Adiabatic pulse design

A method of NMR (nuclear magnetic resonance) excitation of a sample having a magnetic moment, including, applying a longitudinal magnetic field to the sample; and changing the magnetic moment in a substantially continuous manner by moving an effective magnetic-field vector &ohgr; more than 90&deg;, wherein for all portions of the sample in which the moment is changed, the angular velocity of the effective field vector at at least one angle, 90&deg;&plus;&agr;, is different from the angular velocity at 90&deg;&minus;&agr;.

Frequency selective pulse

A method of compensating for an eddy field according to measurements of the field. The method includes fitting the measurements of the field to a plurality of candidate models of the field. A stability value indicative of the stability of the fitted model to changes, is assigned to each of the fitted candidate models. A model is selected from the candidate models responsive to the stability values of the candidate models and the eddy fields are compensated responsive to the selected model.

Eddy current compensation

New methods of generating optimal inversion pulses and adiabatic pulses in magnetic resonance imaging are disclosed. Trajectories, maximum sweep rates, and velocity profiles are used in defining an optimal pulse, over support regions. Adiabatic pulses are optimized by using the trajectory as a constraint of optimization, but selecting trajectories with velocity profiles, without using the adiabatic condition as a constraint for optimizing the velocity profile. A method or inverting MR spins substantially, independently of the pulse duration, by selecting a transition width between 1.4 and 1.9 and dividing that width by the pulse duration is disclosed; and A new method of inverting adiabatic, MR, amplitude modulated spins, with a trajectory defined by sin .alpha./cos .alpha., where .alpha.&lt;0.9 and at least 50% of the trajectory is outside, in a z-x rotating frame of reference that rotates at the instantaneous frequency of the RF pulse is also taught.

Fast adiabatic pulses

A magnetic resonance angiography method for acquiring angiographic images using any or all of three different types of selective presaturation pulses to the particular parts of the body for enhancing vascular imaging. The three types are:

Artifact reduction in magnetic resonance angiographic images

A magnetic resonance imaging system that:

Evolving image

Elimination of truncation artifacts in Magnetic Resonance Images is accomplished by analaytically optimizing controllable parameters; i.e., filter characteristic and assymetry ratio when asymetrically sampling arid time domain filtering followed by complex conjugating the filtered data to reduce the Gibbs artifact.

Reduction of truncation caused artifacts

A system corrects for phase angles degradation due, for example to eddy currents, and uses the corrected phase angles to determine flow. The system acquires flow compensated low resolution images and uncompensated low and normal resolution images of a flowing fluid. The images include phase angle data. The phase angle data of the low resolution images are subtracted from the corresponding phase angle data of the normal resolution images to obtain phase angle corrected compensated and uncompensated images. The phase angle corrected compensated images are subtracted from the phase angle corrected uncompensated images to obtain flow images with minimized phase angle distortion. Reliable and accurate flow velocity for each pixel is thereby obtained using the minimized phase angle distortion flow images.

Growing community of inventors

Haifa, Israel

Yuval Zur