Koninklijke Philips Corporation N.V.

U.S. Philips Corporation

Bell Telephone Laboratories

N.v. Philips' Gloeilampenfabrieken

Bernd E Aldefeld

Peter Boernert

Michael Harald Kuhn

Johannes Adrianus Overweg

Jochen Keupp

Peter Bornert

Dirk Manke

Volker Rasche

Holger Eggers

Kay Nehrke

Hermann Schomberg

Erhard Paul Artur Klotz

Markus Weiger

Stephen E Levinson

Friedrich-Karl Beckmann

Dietrich J Holz

Georg Weidinger

Thomas G Szymanski

Rolf Udo Dieter Kobs

A plurality of global receive coils () are stationarily positioned around a fixed field of view (FOV) of a magnetic resonance diagnostic imaging device (). Each global receive coil receives undersampled phase and frequency encoded data from the stationary field of view. A subject is imaged as it moves continuously through the fixed field of view such that data is collected over a virtual field of view (vFOV) of the subject which is longer than the field of view in a longitudinal direction of subject motion. Centrally encoded k-space data, acquired from each of the global receive coils, is used to generate coil sensitivity patterns () which are mapped () from the stationary field of view to the virtual field of view. A SENSE reconstruction processor () performs a SENSE reconstruction on the virtual field of view data in which reconstructed data is combined and unfolded in accordance with the virtual field of view sensitivity patterns () to generate a virtual field of view image representation ().

Fast continuous moving bed magnetic resonance imaging with multiple stationary receive coils for sense reconstruction

A continuous table motion magnetic resonance imaging system includes a processor () for determining values of scan parameters including at least a subject velocity, a field of view length in the direction of the table velocity, and a preparation sequence time. The acquisition includes performing one or more preparatory operations () to manipulate image contrast or to update scanning parameters during table motion. A table () is provided for continuously moving a supported imaging subject at the determined velocity. A magnetic resonance imaging scanner () through which the table continuously moves the subject acquires magnetic resonance imaging data of the imaged subject during the continuous moving using the determined scan parameters. A reconstruction processor () reconstructs the acquired data into an image of the field of view.

Continuous moving-table MRI contrast manipulation and/or update of scanning parameters

A device for determining the position of a medical instrument that is introduced into an object to be examined is also used for imaging the vicinity of the medical instrument. In order to enable the acquisition of instantaneous position information and image information from the vicinity of the medical instrument for all kinds of medical instruments, a localization device that is arranged in the end zone of the medical instrument that is to be introduced determines the position of the medical instrument within the object to be examined; at the same time image information is acquired in the vicinity of the medical instrument by an image acquisition device that is arranged on the medical instrument and on the basis of the position thus determined the position of the medical instrument ( ) is reproduced in a survey image of the object to be examined and images of the vicinity of the object to be examined are displayed on the basis of the image information acquired.

Method and apparatus for intravascular localization and imaging without X-rays

The invention relates to an MR method wherein disturbing MR signals from peripheral regions outside the isocenter are suppressed in that a location-dependent, brief, steady magnetic field is produced simultaneously with an RF pulse. When the field strength of the magnetic field in the peripheral regions is either larger or smaller than that at the isocenter, it can be achieved that exclusively the nuclear magnetization in the peripheral regions is excited, which magnetization can subsequently be dephased. The subsequent MR sequence then influences only the region around the isocenter.

MR apparatus and gradient saturation method for suppressing MR signals from peripheral regions situated outside an isocenter

A vertical field type MRI apparatus is provided with a superconducting coil system for generating a substantially homogeneous magnetic field in an imaging volume of the apparatus. The coil system includes a circular outer coil and a supplementary coil which is positioned in the same plane as and within the outer coil, which coils conduct opposite currents. The ratio D /D of the diameter D of the supplementary coil to the diameter D of the outer coil lies between 0.7 and 0.9. Further coils for making the field more homogeneous are preferably located on a conical surface within the circular outer coil and supplementary coil in such a manner that a recess is formed in which a conically shaped gradient coil system can be accommodated, with the result that the expensive outer coil and the supplementary coil can be arranged at an as short as possible distance from the space for receiving the patient to be examined.

Vertical field type MRI apparatus with a conical gradient coil situated in the main magnet

An MR imaging method wherein motion of an object to be imaged is examined during a preparation phase preceding the actual MR examination. The necessary sequences for the subsequent MR examination are modified during the examination to compensate for the motion based on motion parameters calculated during the preparation phase or motion parameters derived from the motion parameters calculated during the preparation phase based on a correlation between the motion parameters.

MR imaging method with motion compensation

The invention enables the temporal variation of the magnetic field generated by a gradient coil to be derived from the measured temporal variation of the current through this gradient coil and from a pulse response which has been determined once and stored for the relevant coil. In this case an inexpensive non-linear amplifier may be used in the gradient channel, and also a gradient coil with eddy current effects, without the reconstruction or the pulse design being degraded.

Magnetic resonance method

The invention relates to an MR method in which the deterioration of the image quality by the concomitant gradients is reduced or eliminated by imposing a temporal variation on the magnetic fields acting in the examination zone during the time interval between the excitation of the nuclear magnetization and the reception of the MR signal such that the spatial distribution of the phase error upon reception of the MR signal is at least approximately the same for all sequences.

MR method

The invention relates to a method of navigating a magnetic object (,) within an object (,) which is exposed to a magnetic field, as well as to a magnetic resonance device in which this method can be carried out. The method according to the invention is particularly suitable for navigating a catheter or a flexible endoscope within the body of a patient. The magnetic object (,), preferably being provided in or on such a medical instrument (,), has a controllable magnetic moment for this purpose and the direction of movement of the object is determined by control of the magnetic moment. In the case of a magnetic resonance device whose static magnetic field is used, the object (,) is preferably includes as a coil system.

Method of navigating a magnetic object, and MR device

The invention relates to an MR method and an MR device for determining the position of at least one microcoil (11, 12) which is provided in or on an object (1) to be examined which is situated in an examination zone. During the acquisition of microcoil MR signals (S), at least one variable magnetic gradient field acts on the examination zone, so that the k space is scanned at scanning points (k.sub.x (t.sub.i), k.sub.y (t.sub.i)). The position (x, y) of the microcoil (11, 12) is determined from at least three scanning values (S(t.sub.i)) of a microcoil MR signal and the associated scanning points (k.sub.x (T.sub.i), k.sub.y (t.sub.i)) for example by solving a system of equations formed from these values. The MR method can be used for various scanning modes of the k space, and the acquisition of the microcoil MR signals (S) does not require any MR sequences other than the MR sequences required for determining the nuclear magnetization distribution in the examination zone.

MR method and MR device for determining the position of microcoil

In an MR method whereby artefacts can be eliminated in MR images of inclined slices which are situated outside the isocenter, the temporal variation of a phase error is calculated from the imposed (desired) variation of the magnetic gradient fields and the impulse responses of the gradient coil sub-systems generating these fields, and the measured MR signals are corrected accordingly.

MR method and device for carrying out the method

The invention relates to an actuation magnet for a printing stylus (11) of a matrix printer, in which an armature (12) of the plunger type connected to the printing stylus (11) is guided in the cylindrical inner space of two soft-magnetic pole pieces (6,7) enclosed by a direct current energizing coil (14), the space between these pole sleeves (6,7) being bridged by a spacer element (17), which consists of a material, whose magnetic conductance or permeance is considerably smaller than that of the material of the pole sleeves (6,7). The movement force exerted on the soft-magnetic armature (12) is increased in that the distance between the ends of a yoke (13) is bridged by a permanent magnet (17), whose pole faces engage the free ends of the yoke (13), and in that the energization of the energizing coil (14) produces a magnetic flux, which has a sense opposite to a magnetic flux of the permanent magnet (17) through the yoke (13).

Actuation magnet for a printing stylus of a matrix printer

A string of input characters is recognized as one of a plurality of reference sets which are stored in predetermined groups. A set of signals representative of the correspondence of the input characters to the reference characters is generated. The input character string is identified responsive to the character correspondence signals. The character string identification comprises forming a set of signals each representative of the correspondence of the input character string to one of the predetermined groups responsive to the character correspondence signals. Jointly responsive to the character correspondence signals, the reference character sets and the group correspondence signals, the reference set that most closely corresponds to the input character string is selected.

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Hamburg, Germany

Bernd E Aldefeld