Koninklijke Philips Corporation N.v.

Johns Hopkins University

The United States of America, As Represented by the Secretary, Department of Health and Human Services

Other

Daniel Alfredo Herzka

John Andrew Derbyshire

Elliot R McVeigh

Sandeep Narendra Gupta

Richard Winkelmann

Liheng Guo

Garth M Beache

A magnetic resonance imaging (MRI) system, comprising a magnetic resonance imaging scanner. The MR scanner comprises a main magnet providing a substantially uniform main magnetic field B0 for a subject under observation, the subject represented by a spatial distribution of magnetizations; a radio frequency (RF) coil system configured to irradiate a plurality of radio frequency (RF) pulses into a region of interest of the subject and to detect a plurality of RF response signals emitted from the region of interest; a gradient coil system configured to provide a perturbation of the main magnetic field B0 using a gradient pulse sequence that causes the RF response signals to encode the spatial distribution of magnetizations in a Fourier domain on a plurality of read-out paths; and a controller in communication with the RF coil system and the gradient coil system to synchronously provide the RF coil system with the plurality of RF pulses and the gradient coil system with the gradient pulse sequence. The gradient pulse sequence comprises a navigator pulse that causes one of the plurality of RF response signals to encode the spatial distribution of magnetizations in the Fourier domain on a pre-determined navigator path that represents a fixed projection of the region of interest of the subject, the pre-determined navigator path is suitable to be in a direction different from directions of the read-out paths, and the fixed projection of the subject is capable of tracking a motion of the subject.

Apparatus and method for magnetic resonance imaging with high spatial temporal resolutions

An embodiment in accordance with the present invention provides concurrent measurement of motion during T2-weighted magnetic resonance imaging. The present invention combines T2 preparation, a module used to impart T2 contrast, and motion measurement, tracking, and/or correction. The present invention provides for the expedition of more efficient motion compensation during T2-weighted imaging. The proposed invention can be used to provide a variety of measurements of motion, with no overhead in imaging time. The proposed invention also enables T2 contrast imaging to be executed while a subject is breathing freely, without the additional time cost associated with the standard motion tracking methodologies.

Integration of T2-preparation and motion tracking in magnetic resonance imaging

In an imaging method, periodic maintenance radio frequency pulses (&#x3b1;, &#x2212;&#x3b1;) are applied to maintain a steady state magnetic resonance excitation in an imaging region. Readout () of imaging data from the imaging region is performed during selected intervals between maintenance radio frequency pulses. A spatially selective blood signal suppression sequence (') is performed during selected other intervals between maintenance radio frequency pulses. The blood signal suppression sequence suppresses a blood signal in a suppression region different from the imaging region. The blood signal suppression sequence has substantially no zero the moment applied magnetic field gradient.

Black-blood steady-state free precession magnetic resonance imaging

A method for fat-suppressed imaging is disclosed. Such a method may include storing a first spectral component of an echo signal formed at TR/2 from a sample, suppressing a second spectral component of the echo signal at TR/2, re-exciting the stored spectral component after suppressing the second spectral component, and producing an image of the sample based on the re-excited stored spectral component.

Spectrally selective suppression with steady-state free precession

In a coherent magnetic resonance imaging method, a plurality of slices () are each prepared () in a steady spin state. Time domain multiplexed readouts () are performed. Each readout acquires magnetic resonance data corresponding to one of the steady spin state slices. Radio frequency excitation pulses () are interleaved with the time domain multiplexed readout pulses () to maintain the steady spin states of the slices. The acquired magnetic resonance data are reconstructed () to produce reconstructed images corresponding to the plurality of slices.

MR multi-slice steady state free precession imaging

A method that exploits the intrinsic selectivity of steady-state free precession (SSFP) to perform spectral suppression is disclosed. Such a method avoids the need to incorporate additional spectrally selective pulse sequence elements. The scheme is based on breaking the FISP imaging sequence into short trains having, for example, 8&#x2013;64 RF pulses. At the moment of echo formation (i.e., TE=TR/2) after the last full RF pulse of the train, water signal is z-stored. Residual transverse magnetization, which include isochromats phase-opposed to the on-resonance water, is gradient crushed and RF spoiled. The stored magnetization is subsequently re-excited with little disturbance to the on-resonance steady-state water signal. The additional time required to perform the steady-state interruption is typically as little as a single TR, minimally affecting the efficiency of the imaging process. The sequence can be employed repetitively, greatly reducing the amplitude of fat signals throughout a real-time or cine imaging process.

The present invention is a method and apparatus for semi-automatically registering low signal to noise ratio relaxation-time images, with particular application to tracking motion in moving organs and quantifying myocardial perfusion reserve. For each image acquired in a time series, a corresponding high signal to noise ratio image is extrapolated from the collected data. The high signal to noise ratio images are registered to track motion, and the resulting registration data is copied onto the corresponding relaxation time image.

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Rockville, MD, United States of America

Daniel Alfredo Herzka