General Electric Company

Wisconsin Alumni Research Foundation

Yong Zhou

Kevin Franklin King

Richard Frayne

The present invention provides a system and method of reducing image intensity variations during imaging acquisitions that utilize large encoding gradient pulses that are played out immediately before a center of k-space is sampled. The present invention includes an acquisition and sampling that implements a predetermined delay in sampling prior to sampling the center of k-space. The delay in sampling the center of k-space following sampling of a peripheral region of k-space maintains the steady state of the MR signal and reduces the image intensity variation caused by eddy current and gradient hysteresis. As such, the intensity variations throughout k-space may be reduced substantially and brought closer to the intrinsic noise level of the data acquisition.

Method and apparatus to reduce image intensity variation during MR data acquisition

Methods and Systems for image reconstruction in magnetic resonance imaging (MRI) are provided. The method includes receiving MRI data and storing the received MRI data. The method further includes reordering the stored MRI data during an image reconstruction.

Method and system for performing image reconstruction in a magnetic resonance imaging system

A method of measuring and correcting eddy currents in a MRI system includes running a pulse sequence using bipolar gradient pulses and a first delay Te, to acquire a phase-difference image and a phase response of a static phantom that fills a majority of a field of view (FOV) of the MRI system, fitting the phase difference image to a two-dimensional second order polynomial, and changing the pulse sequence to provide a different delay. The method includes iterating running a pulse sequence and fitting the phase difference image and phase response with different delays to determine coefficients of the second order polynomial and a time constant of the phase response, correcting a pre-emphasis eddy current correction (ECC) system of the MRI system in accordance with the time constant of the phase response, determining an amplitude correction to reduce determined coefficients, and storing determined amplitude corrections in the pre-emphasis ECC system.

Eddy current measurement and correction in magnetic resonance imaging systems with a static phantom

NMR images indicative of thermal changes in tissues undergoing therapy are produced using a gradient-recalled echo pulse sequence. Prior to therapy a contrast agent which shortens spin T relaxation time is injected into the patient and a reference phase image indicative of proton chemical shift is acquired. Temperature maps are produced in real-time as the therapy is subsequently performed by repeatedly acquiring NMR data, reconstructing measurement phase images and subtracting the reference phase image. The temporal rate at which the temperature maps are produced is increased by segmenting k-space and acquiring less than all the segments during each repetition.

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Waukesha, WI, United States of America

Yong Zhou