The University of Texas System

Ge Medical Systems Global Technology Company, LLC

General Electric Company

University of Pennsylvania

Ge Medical Technology Services, Inc.

Jingfei Ma

Guosheng Tan

Graeme Colin McKinnon

Xiaohong Zhou

James A Bankson

R Jason Stafford

Haesun Choi

Kevin Franklin King

Richard Scott Hinks

Yuval Zur

Ersin Bayram

Saban Kurucay

Zachary Slavens

Kang Wang

Ken-Pin Hwang

Daniel V Litwiller

John Hazle

Jong Bum Son

Methods, apparatuses, systems, and software for extended phase correction in phase sensitive Magnetic Resonance Imaging. A magnetic resonance image or images may be loaded into a memory. Two vector images A and B associated with the loaded image or images may be calculated either explicitly or implicitly so that a vector orientation by one of the two vector images at a pixel is substantially determined by a background or error phase at the pixel, and the vector orientation at the pixel by the other vector image is substantially different from that determined by the background or error phase at the pixel. A sequenced region growing phase correction algorithm may be applied to the vector images A and B to construct a new vector image V so that a vector orientation of V at each pixel is substantially determined by the background or error phase at the pixel. A phase corrected magnetic resonance image or images may be generated using the vector image V, and the phase corrected magnetic resonance image or images may be displayed or archived.

Method and apparatus for extended phase correction in phase sensitive magnetic resonance imaging

A method that includes obtaining an MRI gradient echo train of at least three echo data sets at differing phase angles; producing a plurality of phase error maps among the at least three echo data sets; and imaging at least three distinct chemical species based on the plurality of phase error maps.

Method and apparatus for separating chemical species in magnetic resonance imaging

Methods, apparatuses, systems, and software for extended phase correction in phase sensitive magnetic resonance imaging utilizing an optimized region-growing based phase correction algorithm. Phase correction is formulated as selecting a vector for each pixel of an image from two input candidate vectors so that the orientation of the output vector is spatially smooth. In certain embodiments, the optimized region growing algorithm uses automated quality guidance for determining the sequence of region growing and jointly considers the two input candidate vectors during region growing. Further, the algorithm tracks the quality and the mode at each step of the processing. Spatially isolated tissue regions are automatically segmented and processed with different threads of region growing and the correct vector is reliably identified as the output vector for each thread of region growing. Final phase correction was performed by pixel level optimization.

Methods and apparatus for phase correction in magnetic resonance imaging

A single-point Dixon ('SPD') technique that can provide chemical species separation using data from a single echo with a flexible relative phase angle between the species is provided.

Methods of efficient and improved phase-sensitive MRI

A system, program product, and method to determine water, fat, and transverse relaxation time constants in MRI scanning are provided. A method includes initiating readout gradient pulses to collect echo signals with identical phase encoded gradients to thereby produce a plurality of images, instead of a single image with a single readout gradient. A receiver bandwidth used for collecting the echo signals can be determined responsive to an acquisition matrix size along the readout axis and a time duration for water and fat signals to evolve by a preselected phase angle. In a modified FSE implementation, for example, a method includes using readout gradient pulses that use substantially all of the echo spacing time periods between successive refocus RF pulses. By exploiting the phase and the amplitude relationship between the images, the method can include processing the images to generate separate water and fat images, as well as quantitative maps of transverse relaxation time constants.

System, program product, and method of acquiring and processing MRI data for simultaneous determination of water, fat, and transverse relaxation time constants

Systems and methods are described for chemical shift magnetic resonance imaging in the presence of multiple chemical species. A method includes obtaining a plurality of MRI data signals using a Dixon technique in combination with partially parallel imaging techniques and/or inversion recovery techniques, and processing the plurality of MRI data signals using a Dixon reconstruction technique to create a chemical specific shift image. An apparatus includes a MRI scanner for obtaining images, a controller configured to provide input to the scanner to acquire images using a Dixon technique in combination with partially parallel imaging techniques and/or inversion recovery techniques to produce a plurality of MRI data signals, and processing the plurality of MRI data signals using a Dixon reconstruction technique to create a chemical specific shift image, and an output device to display the resulting image.

Methods and apparatuses for fast chemical shift magnetic resonance imaging

Systems and methods are described for phase-sensitive magnetic resonance imaging using an efficient and robust phase correction algorithm. A method includes obtaining a plurality of MRI data signals, such as two-point Dixon data, one-point Dixon data, or inversion recovery prepared data. The method further includes implementing a phase-correction algorithm, that may use phase gradients between the neighboring pixels of an image. At each step of the region growing, the method uses both the amplitude and phase of pixels surrounding a seed pixel to determine the correct orientation of the signal for the seed pixel. The method also includes using correlative information between images from different coils to ensure coil-to-coil consistency, and using correlative information between two neighboring slices to ensure slice-to-slice consistency. A system includes a MRI scanner to obtain the data signals, a controller to reconstruct the images from the data signals and implement the phase-correction algorithm, and an output device to display phase sensitive MR images such as fat-only images and/or water-only images.

Method and apparatus for phase-sensitive 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

An improved technique is described for acquiring MR image data such as needed for FSE-based Dixon imaging techniques. A gradient-induced echo shift is produced in the pulse sequences by a small gradient applied along the readout axis prior to a readout pulse. When necessary, another small pulse is applied along the readout axis, equal in area and opposite in polarity to the first, to compensate for the shifting effect. Similar pulses are applied for each acquisition window. While data with non-zero phase shifts between water and fat signals are collected as fractional echoes, no increase in echo spacing is necessary with the modified acquisition strategy. Images corresponding to different phase shifts are reconstructed using phase-sensitive partial Fourier reconstruction algorithms whenever necessary. These images are then used to separate different chemical species (such as water and fat) in the object to be imaged. Increased time efficiency is therefore achieved with the improved technique, with a significant reduction in degradation due to losses in slice coverage and increased image blurring and sensitivity to flow and motion due to T2-modulation along the echo train in conventional techniques.

Data acquisition method and apparatus for MR imaging

An automatic and adaptive MR data selection technique for use with a multi-receiver coil assembly in an MR imaging device is disclosed. The invention includes acquiring image data from a plurality of receiver coils and determining an index gauge for each of the images. The index gauge is a representation of the position of a given receiver coil within a desired field-of-view (FOV). The index gauges are compared and any image data set having an index gauge demonstrating a less than optimal position of the given receiver coil with respect to the desired FOV is removed based on the index gauges and the comparison. A final image can be reconstructed using the remaining image data sets. The final image is reconstructed from data having overall reduced noise, and therefore reduced artifacts.

Adaptive data differentiation and selection from multi-coil receiver to reduce artifacts in reconstruction

Automatic coil selection is based on determining an index gauge for a corresponding k-space data line acquired for each preselected coil during a prescan. Reliance on manual coil selection and markers is eliminated by adaptively determining the coils of an MR system that produce a preferred sensitivity to a desired field-of-view (FOV). The fast scan data is used to determine those coils most sensitive to the FOV and reject coil(s) least sensitive. Using only data acquired with the most sensitive coils, SNR is increased and unwanted artifacts are reduced in the final data acquisition and image reconstruction. Through automatic and adaptive selection/deselection, the invention reduces the susceptibility to human error, and therefore results in higher quality images.

Growing community of inventors

Houston, TX, United States of America

Jingfei Ma