General Electric Company

Leland Stanford Junior University

Wisconsin Alumni Research Foundation

Beth Israel Deaconess Medical Center, Inc.

Huanzhou Yu

Scott Brian Reeder

Charles McKenzie

Angel R Pineda

Norbert Joseph Pelc

Jean Helen Brittain

Ann Shimakawa

David C Alsop

Ananth J Madhuranthakam

Zhifei Wen

Anja Brau

An apparatus and method for separating the NMR signal contributions from a plurality of different species having different chemical shifts is disclosed. The apparatus acquires MR image data sets including a first species signal and a second species signal, generates a first species image from the acquired MR image data, and generates a second species image from the acquired MR image data. The apparatus also identifies voxels in the second species image representative of only the second species and, for voxels identified as being representative of only the second species, calculates a fraction of the second species signal appearing in the first species image. The apparatus generates a modified first species image based on the fraction of the second species signal appearing in the first species image, with the modified first species image having a different fraction of the second species as compared to the first species image.

System and method for fat suppression in chemical shift based water-fat separated MR imaging

Methods are disclosed for calculating a fat fraction corrected for noise bias of one or more voxels of interest using a magnetic resonance imaging (MRI) system. A plurality of image data sets are obtained each corresponding to NMR k-space data acquired using a pulse sequence with an individual associated echo time t. A system of linear equations is formed relating image signal values to a desired decomposed calculated data vector having a component such as a water and fat combination having zero mean noise, or having a real fat component and a real water component. A fat fraction is calculated from at least one component of the decomposed calculated data vector. In another embodiment, the system of linear equations is normalized and can directly estimate a fat fraction or a water fraction having reduced noise bias.

Methods for fat quantification with correction for noise bias

A method for producing an image of a subject with a magnetic resonance imaging (MRI) system in which a signal contribution of a chemical species is depicted and a signal contribution of another chemical species is substantially separated is provided. For example, the provided method is applicable for water-fat separation. Spectral differences between at least two different chemical species are exploited to produce a weighting map that depicts the likelihood that one chemical species being depicted as another. A weighting map that characterizes the smoothness of a field map variation is also produced. These weighting maps are utilized to produce a correct field map estimate, such that a robust separation of the signal contributions of the at least two chemical species can be performed.

Method for separating magnetic resonance imaging signals using spectral distinction of species

Methods and systems are provided for processing a magnetic resonance images. In one embodiment, first and second sets of lines of magnetic resonance imaging signals are acquired. The acquired sets of lines have readout gradients that are reversed in polarity with respect to one another. A two-dimensional phase error is determined using the first and second set of lines.

Method and system to perform phase correction for species separation in magnetic resonance imaging

NMR signal contributions from water and fat are separated using a model of the fat resonant frequency spectrum that has multiple resonant peaks. The relative frequencies of the multiple fat spectrum peaks are known a priori and their relative amplitudes are determined using a self-calibration process. With the determined relative amplitudes of the fat spectrum peaks, acquired NMR signals are modeled. Using this model and NMR signal data acquired at a plurality of echo times (TE), the signal contribution from multiple fat spectrum peaks is separated from the acquired NMR signal data. A combined image is alternatively produced from weighted contributions of the separated water and fat images. Additionally, a more accurate estimation of the apparent relaxation time and rate (T*and R*, respectively) is alternatively performed.

[object Object]

A method of separating signals from at least two species in a body using echo-coherent time magnetic resonance imaging is provided. A plurality of echo signals is acquired at acquisition times optimized based on the noise properties of images with different variance with possibly correlated noise resulting in possibly asymmetrically positioned images with respect to an echo time. The plurality of echo signals is combined iteratively by using a maximum likelihood decomposition algorithm for non-identically distributed noise.

Maximum likelihood estimator in the presence of non-identically distributed noise for decomposition of chemical species in MRI

A method for generating a magnetic resonance images is provided. A magnetic resonance imaging excitation is applied. A plurality of magnetic resonance image signals is acquired. The plurality of image signals is combined iteratively by using a regularized decomposition algorithm. An image created from combining the plurality of image signals iteratively is displayed.

Regularized species separation

A method for generating a self-calibrating parallel multiecho magnetic resonance image is provided. A magnetic resonance imaging excitation is applied. A first echo at a first echo time in a first pattern is acquired. A second echo at a second echo time different from the first echo phase in a second pattern different from the first pattern is acquired. The acquired first echo and acquired second echo are used to generate an image in an image pattern, wherein none of the acquired echoes for generating the image have the same pattern as the image pattern.

Self-calibration methods for parallel imaging and multipoint water-fat separation methods

A method for generating dynamic magnetic resonance images is provided. A cyclical magnetic resonance imaging excitation is applied for a plurality of cycles at a cycle rate. A plurality of magnetic resonance image echoes is acquired for each cycle. A plurality of frames of images is generated from the acquired plurality of magnetic resonance echoes at a frame rate that is at least twice the cycle rate, wherein each frame of the plurality of frames is generated from a plurality of echoes and wherein some of the plurality of frames are generated from magnetic resonance image echoes of adjacent cycles.

Sliding window reconstruction and phase/field map updating for dynamic chemical shift imaging

A method for generating a magnetic resonance image is provided. A magnetic resonance imaging excitation is applied for a plurality of cycles at a cycle rate. A plurality of magnetic resonance image echoes is acquired for each cycle. A decay map is estimated from the plurality of magnetic resonance image echoes for each cycle. The estimated decay map is used to generate an image for at least two different species.

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Mountain View, CA, United States of America

Huanzhou Yu