Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Centre National De La Recherche Scientifique

Université´ D'aix-marseille

Ecole Centrale De Marseille

Siemens Healthcare Gmbh

Siemens Healthineers Ag

Université Paris-saclay

Inria Institut National De Recherche En Informatique Et En Automatique

Alexandre Vignaud

Stefan Enoch

Philippe Ciuciu

Pierre Sabouroux

Redha Abdeddaim

Mariappan S Nadar

Boris Mailhe

Michel Luong

Nicolas Boulant

Alexis Amadon

Nicolas Bonod

Vincent Gras

Eric Giacomini

Benoit Larrat

Guillaume Daval-Frerot

Gérard Tayeb

Abdeddaim Redha

Gérard Henri Jacques Tayeb

Chaithya Giliyar Radhakrishna

Guillaume Daval Frerot

Elodie Virginia Emilia Georget

Aurelien Massire

Mathilde Ripart

Anne-Lise Adenot-Engelvin

Raphaël Tomi-Tricot

Lisa Marie Anna Leroi

Zo Raolison

Pierre Weiss

Edouard Chazel

Marc Dubois

Nicolas Mallejac

Elodie Georget

Nicolas Chauffert

Bertrand Thirion

Jonas Kahn

Carole Lazarus

A method of performing magnetic resonance imaging of a body using a magnetic resonance imaging scanner the method includes applying to the body a time-varying magnetic field gradient (G, G, G) defining a continuous trajectory (ST) in k-space complying with a set of constraints including constraints on maximum amplitude and maximum slew rate of the time-varying magnetic field gradient, such that sampling points (KS) belonging to the trajectory define a pseudo-random sampling of the k-space, approximating a predetermined target sampling density, the trajectory in k-space minimizing, subject to the set of constraints, a cost function defined by the difference between a first term, called attraction term, promoting consistency of the distribution of sampling points in k-space with the predetermined target sampling density, and a second term, called repulsion term, promoting separation in k-space between sampling points, the repulsion term being expressed as a sum of contributions corresponding to respective pairs of sampling points; wherein each the contribution is weighted by a weight which increase with temporal separation of the sampling points along the trajectory in k-space.

Method and apparatus for performing accelarated magnetic resonance imaging with reduced off-resonance effect

The invention relates to a material for use as a pad in high field and/or very high field magnetic resonance imaging instrument, comprising at least one polar solvent having a melting point of 14° C. to 50° C., a dispersant and a dielectric charge. The invention relates also to a pad used in field of high field and/or very high field magnetic resonance imaging made of at least such a material.

Materials with high dielectric constant for magnetic resonance imaging instruments

A magnetic resonance (MR) image may be created from MR data by receiving the MR data, applying a transform to the MR data, where a result of the applying is an image space representation of the MR data, determining a wrapped phase map of the image space representation of the MR data, obtaining an unwrapped phase map based on the wrapped phase map, scaling the unwrapped phase map into a B0 field map, reconstructing the MR image based on the MR data, correcting the MR image based on the B0 field map, and outputting the MR image. The scaling may be free of accounting for effects on the MR data by artifact sources secondary to B0 field inhomogeneities.

B0 field inhomogeneity estimation using internal phase maps from long single echo time MRI acquisition

A method of performing magnetic resonance imaging of a body includes a) immerging the body in a static and substantially uniform magnetic field; b) exciting nuclear spins inside the body using at least one radio-frequency pulse; c) applying to the body a time-varying magnetic field gradient defining at least one trajectory (ST) in k-space and simultaneously acquiring samples of a magnetic resonance signal so as to perform a pseudo-random sampling (KS) of the k-space; and d) applying a sparsity-promoting nonlinear reconstruction algorithm for reconstructing a magnetic resonance image of the body; wherein, at least in a low-spatial frequency region of the k-space, the distance between any two adjacent points belonging to a same trajectory is lower than 1/FOV, FOV being the size of a field of view of the reconstructed image. A magnetic resonance imaging apparatus for carrying out such a method is also provided.

Method and apparatus for accelerated magnetic resonance imaging

A computer-implemented method of building a database of pulse sequences for parallel-transmission magnetic resonance imaging, includes a) for each of a plurality of subjects, determining an optimal sequence for the subject; b) for each subject, computing the values of the or of a different cost or merit function obtained by playing the optimal sequences for all the subjects; c) aggregating the subjects into a plurality of clusters using a clustering algorithm taking the values, or functions thereof, as metrics; d) for each cluster, determining an averaged optimal sequence for the cluster; e) receiving, as input, a set of features characterizing an imaging subject, comprising at least a morphological feature of the subject; f) associating the subject to one pulse sequence of the database based on the set of features using the computer-implemented classifier algorithm; and g) performing magnetic resonance imaging using the pulse sequence. A magnetic resonance imaging apparatus for carrying out steps e)-g) of such a method is also provided.

Computer-implemented method of building a database of pulse sequences for magnetic resonance imaging, and a method of performing magnetic resonance imaging using such a database

A method for controlling the distribution of the RF magnetic field in a magnetic resonance imaging system, having steps of: placing a cage coil in a permanent magnet supplying a permanent magnetic field along a first axis, and supplying an RF signal to the cage coil in order for the coil to generate an RF magnetic field rotating in a plane that runs perpendicular to the first axis; and putting in place an electromagnetic resonator, the resonance mode of which is excited by the rotating magnetic field, the resonator being placed in a position inside or outside the cage coil and at a distance from a region to be analyzed of an object to be placed in the cage coil, the resonance mode and the position of the resonator in relation to the volumetric antenna being suitable for adjusting the intensity of the rotating magnetic field in an area of the region to be analyzed.

Method for controlling the distribution of the RF magnetic field in a magnetic resonance imaging system

An antenna array includes a plurality of linear electromagnetic resonators having longitudinal axes oriented parallel to one another and not aligned, and at least one decoupling device arranged between two the linear electromagnetic resonators, wherein the decoupling device comprises a plurality of open-loop electromagnetic resonators that are matched to a frequency located in the bandwidth of the two the adjacent linear electromagnetic resonators, that are electrically insulated and that are arranged in a plurality of planes that are not parallel to a plane containing the longitudinal axes of the two the linear electromagnetic resonators. Nuclear magnetic resonance imaging apparatus comprising such an antenna array is also provided.

Antenna array, in particular for magnetic resonance imaging, comprising linear electromagnetic resonators and at least one decoupling device

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Paris, France

Alexandre Vignaud