General Electric Company

General Electric Corporation Gmbh

Leland Stanford Junior University

General Elecric

University of California

Ralph Eugene Hurd

Napapon Sailasuta

Boban K John

Harris D Plant

Ileana Hancu

Patrick L Le Roux

James S Tropp

Daniel Mark Spielman

Daniel Blackburn Vigneron

John Kurhanewicz

Albert Po-Fu Chen

Susan Jean Kohler

Yakir Levin

Zhong-Min Hu

Dirk Mayer

Michael G Boucher

Sarah Jane Nelson

A system for magnetic resonance (MR) spectroscopy includes a plurality of gradient coils positioned about a bore of a magnet and an RF coil assembly coupled to a pulse generator to emit RF pulse sequences and arranged to receive resulting MR signals from a subject of interest. A system control is also included in the MR spectroscopy system and is coupled to the plurality of gradient coils and the RF coil assembly. The system control is programmed to cause the RF coil assembly to emit a first RF pulse and a second RF pulse, wherein at least one of the first and second RF pulses is spectrally selective and at least one of the first and second RF pulses is spatially selective. The system control is also programmed to cause the RF coil assembly to emit a third RF pulse after a pre-defined time delay to generate a stimulated echo and detect MR signals resulting from the stimulated echo.

System and method for tissue specific MR imaging of metabolites using spectral-spatially formed stimulated echo

The use of selective RF excitation is discussed. A spectrally selective, large tip angle RF pulse is used to detect a weak signal from a first chemical species. A non-selective, small tip angle pulse is used in measuring a signal from a second chemical species in exchange with the first chemical species. The acquired resonance data provides maybe used to measure the ratio of the spectrally distinct species in exchange.

Measurement of chemical equilibrium ratio using a magnetic resonance spectroscopy system

A system and method for improving available signal-to-noise ratio (SNR) and speed of MR imaging of hyperpolarized substances is disclosed. The system and method include decoupling spin effects of hydrogen nuclei from non-hydrogen nuclei of interest during sampling of MR signals therefrom. Though the hydrogen nuclei of the hyperpolarized substance may not be directly bonded to the non-hydrogen nuclei of interest, resonance splitting may still impact SNR. Long range decoupling improves T2* time, and thus preserves signal strength and available SNR.

Proton decoupled hyperpolarized magnetic resonance imaging

A method for increasing sensitivity and/or specificity of a magnetic resonance spectroscopy imaging technique for detecting a neurodegenerative disease is provided. The method includes acquiring magnetic resonance spectroscopy data from the brain of a subject, while suppressing certain metabolites in the spectrum via a data acquisition protocol, to improve quantification accuracy for the remaining metabolites, and quantifying a metabolite concentration or a metabolite concentration ratio from the spectral data as an indicator of the neurodegenerative disease.

Methods and systems for detection and monitoring of neurodegenerative diseases using magnetic resonance spectroscopy

A method of imaging the individual components of systems with sparse spectra using magnetic resonance imaging including the steps of a) exciting nuclei of labeled components using a MRI pulse sequence, b) selecting a proper spectral window to avoid/minimize signal overlap of aliased frequency components. In step a) preferably a spiral chemical shift imaging (spCSI) sequence is employed. In a preferred embodiment, hyperpolarized nuclei ofC are used for labeling in a pyruvate substrate with metabolites of lacatate, alanine, and bicarbonate.

Fast metabolic imaging of systems with sparse spectra using spiral CSI

A technique is set forth for MR spectroscopy that is capable of reducing signal overlap between metabolite signals for improved clinical analysis of metabolite content. The technique includes varying an echo time across a scanning dimension. Once a span of echo time for an acquisition dimension is determined, and the number of acquisition data points is known, a variance between echo times can be determined. A pulse sequence with differing echo times is then applied for each frame, and after data is acquired, an image is reconstructed that significantly improves metabolite signal separation.

Method and apparatus for improved metabolite signal separation in MR spectroscopy

A system and method for imaging is presented that includes exciting water-exchangeable spins in oxygen-bearable molecules in a ROI having a change in oxygen status. A proton transfer within the ROI from exchangeable protons within water is detected such that changes in oxygen levels across the ROI are distinguishable.

Method and system of mapping oxygen concentration across a region-of-interest

A field-frequency lock system for an MRI system includes a microcoil and resonant sample located to sense changes in the polarizing magnetic field. Changes are detected as a shift in frequency of the NMR signal produced by the resonant sample, and the frequency shift is used to compensate the MRI system. Compensation is achieved by adjusting the RF reference signal employed in the MRI system transceiver.

Field-frequency lock system for magnetic resonance system

Chemical shift error in proton magnetic resonance spectroscopy is reduced by applying a volume excitation pulse sequence such as PRESS and very selective out-of-volume saturation pulses to limit that volume to a volume-of-interest free of the misregistration errors associated with the excitation sequence. The resulting volume is then only limited by the very small chemical shift misregistration of the very selective saturation pulses.

Magnetic resonance spectroscopic imaging having reduced chemical shift

Disclosed is improved quantitative in vivo spectroscopy by means of F1-oversampled J-Resolved 2D spectroscopy. Reconstruction makes full use of internal signals for 2D water lineshape, T.sub.2 and partial volume correction, and analysis uses 2D complex model spectra fitting. The preferred embodiment of the new method integrates these features into PRESS localized brain spectroscopy and is carried out without the need for water suppression.

Quantitative in vivo spectroscopy using oversampling, waterline

A pure water subtraction method for eliminating interfering sidebands of residual water including spurious signals from extraneous sources such as eddy current effects, Bo magnetic field drift, patient motion and the like. Unsuppressed and partially water suppressed magnetic signal data are obtained, and a low frequency water-phase-correction is applied thereto. The water phase corrected partially suppressed data is subtracted from the water phase corrected unsuppressed data to get a pure water reference (i.e. metabolite signals cancel). A scaled version of the pure water reference is subtracted from the partially suppressed data to eliminate spurious water signals.

Magnetic resonance spectroscopic imaging having reduced parasitic side

Susceptibility artifacts in slice selective volume magnetic resonance spectroscopy are reduced by applying phase encoding at a nominal resolution equal to or larger than the slice selection dimensions. In a preferred embodiment of the method, phase encoding is applied along the axes of the first and last RF slice selections. The volume of interest is contained completely within a single pixel defined by the 2D phase encoding. Unsuppressed water reference signal from the volume of interest is relatively unaffected by these artifacts and is collected without phase encoding.

Volume spectroscopy having image artifact reduction

An MRS or MRI scan is performed by interleaving pulse sequences which acquire MR spectra or images from different locations in a subject. Parameters for the pulse sequence used to acquire MR data at each location are dynamically changed during the scan to optimize the MR measurements.

Growing community of inventors

Milpitas, CA, United States of America

Ralph Eugene Hurd