Koninklijke Philips Corporation N.v.

Marconi Medical Systems, Inc.

Ericsson Ab

David James Larkman

Joseph Vilmos Hajnal

Mark Bydder

David John Gilderdale

John Brian Pendry

Ian R Young

Michael Charles Keogh Wiltshire

Anthony Charles Grantham

David Jonathan Herlihy

Glyn A Coutts

A material having magnetic permeability at r.f. frequency, for example a microstructured magnetic material has a magnetic permeability of negative value but unity magnitude over a particular r.f. frequency range. The singularity in the flux pattern has the result that magnetic resonant disturbances in a plane C,E normal to the line C,D are focussed into a plane D,F also normal to the line C,D and vice versa. This is particularly applicable to magnetic resonance apparatus, since the material can be used to transfer the r.f. magnetic flux distribution in a target region in a patient, for example at C,E to D,F where the flux may be directly measured by receive coils. Equally, transmit coils may generate flux to be focussed into the target region by the material. Magnetic resonance apparatus may be constructed which does not require gradient coils, and r.f. hypothermia may be carried out in a focussed way, minimising damage to surrounding tissue.

Material having magnetic permeability at R.F. frequency

In magnetic resonance imaging apparatus k-space data received from r.f. excitation pulses applied at successive phase-encode gradients and read-out while other gradients are applied is collected for individual coils of an array of r.f. receive coils. A processoruses the lines of data received by each r.f. receive coil at each phase-encode gradient together with reference spatial sensitivity profiles of each coil in a phase-encode direction represented in terms of spatial harmonics of a fundamental frequency one cycle of which corresponds with a desired field of view, to generate a set of phase-encode lines. These lines are converted to image space in Fourier Transform processorto produce an image for display on monitor

Magnetic resonance imaging using generalized smash

In apparatus for magnetic resonance imaging equipped for parallel imaging, in the sense that an array of receive coils can be used to regenerate data at phase-encode gradients interposed between those at which measurements were taken, the full set of data is collected, which is then split into two sets with a greater separation of phase-encode gradients (FIGS.and). These sets are then each regenerated (FIGS.and), enabling spurious data to be excised from the original data set by comparison of the two representations.

Synthesized averaging using SMASH

In an endoscope, the tip which contains passages for viewing and light guiding is made of plastics material, for MR compatibility purposes, and an r.f. receive coil of the endoscope is provided with a fiducial having its own r.f. receive coil, to make it possible to track movement of the r.f. receive coil.

Endoscope suitable for magnetic resonance imaging

Magnetic resonance imaging apparatus uses an array of at least two receive coils to perform parallel processing to enable phase-encode gradients to be omitted during data collection, and restored during processing using parallel processing to further reduce patient time in the apparatus, pre-acquired reference data is used (modules ) to unfold the aliased target data in modules In accordance with the invention, the unfolding is performed against a series of representations of the reference data, varied for translational rotational and coil loading errors, and the unfolded image is chosen as that having the minimum entropy.

Magnetic resonance imaging

In magnetic resonance imaging apparatus employing magnetic gradient fields in a phase-encode and in a read-out direction for spatially encoding excited MR active nuclei in a region of interest of a patient, in which a reduced number of readings in the read-out direction is taken, thereby creating an aliased reduced field of view image, at least two r.f. receive coils are used together with sensitivity information concerning those coils in order to unfold the aliased image to produce a full image while taking advantage of the reduced time of collection of data. In accordance with the invention, sensitivity information is collected at a lower resolution than that at which the image information is collected.

In magnetic resonance imaging apparatus employing magnetic gradient fields in a phase-encode direction for spatially encoding excited MR active nuclei in a region of interest of a patient, in which a reduced number of readings in the phase-encode direction is taken, thereby creating an aliased reduced field of view image, a pair of r.f. receive coils is used together with sensitivity information concerning those coils in order to unfold the aliased image to produce a full image while taking advantage of the reduced time of collection of data. In accordance with the invention, the phase sensitivity pattern of each coil over the region of interest is different from that of the other coil.

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London, United Kingdom

David James Larkman