Bruker Biospin Mri Gmbh

Other

Jochen Franke

Volker Niemann

Rainer Pietig

Michael Herbst

Michael Heidenreich

Ulrich Heinen

Jorge Chacon-caldera

A method for assessing and/or reducing artifacts arising from reconstruction of magnetic particle imaging (MPI) total image data set (c(r)) from MPI signal data (s(f), u(t)) using an appended system matrix (SM_AB) comprises:

Method for assessing and/or reducing artifacts arising from reconstruction of MPI image data and system for visual representation of MPI image data

An MPI imaging device for mapping an object to be examined in a sample volume, with a magnet arrangement which is designed to generate an MPI magnetic field with a gradient B1 and a field-free line in the sample volume, the magnet arrangement comprising a first pair of magnet rings with two magnet rings in a Halbach dipole configuration, which are arranged coaxially on a common Z axis that runs through the sample volume, wherein the magnet arrangement comprises a second pair of magnet rings with two further magnet rings in a Halbach dipole configuration, which is arranged coaxially in relation to the first pair of magnet rings, the magnet rings of both pairs being arranged rotatably with respect to one another about the Z axis. As a result, a variable MPI selection field can be generated by means of permanent magnets.

MPI imaging device, method for generating a magnetic field with a gradient and a field-free line by means of an MPI imaging device

A magnet arrangement for generating a selection magnetic field with a gradient and a field-free region in a sample volume includes: a Maxwell magnet system with two ring magnets, which are arranged in coaxial fashion and at a distance from one another on a common Z-axis extending through the sample volume, a focus field coil arrangement with at least one focus field coil pair for displacing the field-free region within the sample volume, and a drive coil for generating an MPI drive field. The magnet arrangement comprises a quadrupole magnet system with at least one quadrupole ring for generating a quadrupole magnetic field, the quadrupole magnet system being arranged coaxially with respect to the Maxwell magnet system. Using the magnet arrangement according to the invention, it is possible to switch between a selection magnet field with a field-free point and a field-free line without undesirably increasing the field gradient.

Magnet arrangement for generating a selection magnetic field, apparatus with a magnet arrangement and method for generating a selection magnetic field

A hybrid imaging apparatus for imaging an object to be examined located in a sample volume can be operated in an MPI mode and in at least one further imaging mode and comprises a magnet arrangement embodied to generate, in the MPI mode, a magnetic field with a gradient B1 and a field-free region in the sample volume, wherein the magnet arrangement comprises a ring magnet pair with two ring magnets in a Halbach dipole configuration, which are arranged coaxially on a common Z-axis that extends through the sample volume, wherein the ring magnets are arranged so as to be twistable relative to one another about the Z-axis. Consequently, it is possible to generate magnetic fields that meet the requirements of both MRI and MPI such that the hybrid imaging apparatus can be equipped for measurements in various imaging modes, including MPI, MRI and CT.

Hybrid MPI and MRI/CT imaging apparatus and method

A method for establishing and/or reducing artifacts that arise when reconstructing (R) an MPI overall image data record from MPI signal data and an appended system matrix (SMapp(r,f)), wherein the appended system matrix (SMapp(r,f)) includes system matrices of different particle classes (P, P). The method includes setting a selection region (c(r)) of a reconstructed MPI overall image data record (c(r)), producing virtual signal data (s(f)) by inverse transformation of the selection region, reconstructing a virtual overall image data record (c'(r)) from the virtual signal data and the appended system matrix, setting an artifact region (c(r)) within the reconstructed virtual overall image data record so that the artifact region has only voxels lying outside of the selection region, and assigning the image data present in the artifact region as artifact image data (c(r)). This permits ghost artifacts to be corrected.

Method for establishing and/or reducing artifacts, method for establishing a local concentration distribution and system for visually representing a corrected overall image data record

A method for establishing a local concentration distribution of magnetic particles of at least one particle class within an examination volume or a variable derived from this concentration distribution. The method includes providing at least one system matrix, providing MPI signal data of at least one sample including magnetic particles of at least one particle class within a measurement volume, and reconstructing spatially resolved MPI image data from the provided MPI signal data. At least one spatial projection of at least one part of the system matrix is carried out along a projection direction and a projected system matrix is generated thereby. The reconstruction of the MPI image data is implemented with the at least partly projected system matrix, as a result of which MPI image data of a spatial projection of the local concentration distribution of the magnetic particles are produced along the projection direction.

MPI method and system for visually representing MPI image data

An MPI-apparatus comprising a magnet system for generating a time-varying and position-dependent magnetic field and a detection system detecting signals from MPI contrast agents exposed to said magnetic field within a detection volume, said signals being suitable for reconstructing an image of the spatial and temporal distribution of said MPI contrast agents, is characterized in that the magnet system comprises an array with a plurality of permanent magnetic elements geometrically arranged in such a way that at least a part of the plurality of permanent magnetic elements are moved with sufficient speed in the vicinity of the detection volume to create the spatial and temporal magnetic field variations for inducing within the contrast agent the MPI signals recorded by the detection system. This avoids the high power requirements of current MPI scanners, while opening the way for higher spatial resolutions and variable scanning frequencies.

MPI scanner with moving permanent magnetic elements

A device for alternating examination of a measurement object () by means of MPI and MRI with two magnetic field-generating elements is presented. The device is characterized by a main magnet coil system with two coaxial partial coil systems () arranged mirror-symmetrically relative to a central plane running perpendicularly to the z-axis through the first volume under investigation (). The volumes under investigation are superimposed. A polarity reversal device () reverses the polarity of the current through a partial coil system and the main magnet coil system generates a homogeneous magnetic field of at least sixth order in the first volume under investigation when the partial coil systems have identical polarity, and a spatially strongly varying magnetic field profile in the second volume under investigation when the polarities are opposite. Repositioning of the measurement object is thereby simplified or can even be eliminated.

Device for sequential examination of a measurement object by means of MPI and MRI methods

A phantom system has a housing () with a lower part () having an opening in the z-direction and a cover part () for closing the opening of the housing (). A first plate-shaped insert element () has at least one depression () for receiving a liquid substance. The lower part () and the cover part () delimit a cavity () with an insert area (), which is constituted to receive the first insert element (). A first sealing element () seals the first insert element () against the cavity () and a fixing facility fixes the first insert element () in the cavity () of the housing () in an operating state of the MPI phantom. The phantom permits good contrast in MPI, MRI, or &#x3bc;CT using liquid contrast media.

Phantom system, use of the system, and imaging configuration having a phantom system

Device for alternating examination of a measurement object () by means of MPI and MRI within a magnetic system is characterized in that the magnetic system has a specified magnetic field profile, which is not temporally variable during the alternating examination, and both magnetic field generating elements () generate a magnetic field portion, in the first examination region () and in the second examination region (), which is essential for the MRI operation and for the MPI operation, and in that there is a transport apparatus () by means of which the measurement object can be moved out of the first examination region and into the second examination region and/or vice versa. The total space requirement for both modalities is thus reduced and the complexity of an integrally designed hybrid system is minimized.

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Karlsruhe, Germany

Jochen Franke