The Brigham and Women's Hospital, Inc.

Other

Yuly M Pulyer

Samuel Patz

Mirko I Hrovat

Elyena Foster

A planar MRI system is disclosed. The system has an open magnet configuration that produces a magnetic field having a remote region of substantial magnetic field homogeneity. Spatial encoding gradient coils and a rf coil provide MRI data for image reconstruction. The open magnet configuration has a ferromagnetic core with a substantially planar core surface layer and a longitudinal axis, and a unipolar current wire pair on a side of the ferromagnetic core adjacent the planar core surface layer. The wire pair is separated along the longitudinal axis and extends in a direction substantially perpendicular to the axis and substantially parallel to the planar core surface layer. The current wire pair provides a magnetic field having a maximum between the current wire pair along a direction perpendicular to the planar core surface layer and in the remote region of substantial magnetic field homogeneity. The planar core surface layer of the ferromagnetic core provides an orthogonal refractory effect in the form of mirror imaging current wires having the same polarity as the current wire pair that substantially increases the resulting magnetic field compared to a magnetic field generated by the current wire pair in free space.

High efficiency planar open magnet MRI system structured and arranged to provide orthogonal ferrorefractory effect

A planar MRI system is disclosed. The system has an open magnet configuration that produces a magnetic field having a remote region of substantial magnetic field homogeneity. Spatial encoding gradient coils and a rf coil provide MRI data for image reconstruction. A first magnet system having a first ferromagnetic core and a first longitudinal axis with a first pair of coils around the first ferromagnetic core and spaced apart along the first longitudinal axis is located orthogonal to and in substantially the same plane as a second magnet system having a second ferromagnetic core and a second longitudinal axis with a second pair of coils around the second ferromagnetic core and spaced apart along the second longitudinal axis. The open magnet configuration preferably has a ferromagnetic core with a substantially planar core surface layer and a longitudinal axis, and a unipolar current wire pair on a side of the ferromagnetic core adjacent the planar core surface layer. The wire pair is separated along the longitudinal axis and extends in a direction substantially perpendicular to the axis and substantially parallel to the planar core surface layer. The current wire pair provides a magnetic field having a maximum between the current wire pair along a direction perpendicular to the planar core surface layer and in the remote region of substantial magnetic field homogeneity. The planar core surface layer of the ferromagnetic core provides an orthogonal refractory effect in the form of mirror imaging current wires having the same polarity as the current wire pair that substantially increases the resulting magnetic field compared to a magnetic field generated by the current wire pair in free space.

Ferrorefraction MRI system having two orthogonal remote field polarization axes

A magnet resonance imaging system is described having an open magnet structure that provides a remote region of background field homogeneity for imaging that is open and accessible. The system includes spatial encoding gradient coils and a rf coil. The open magnet structure has an planar active shimming coil array that provides a remote region of enhanced field homogeneity with open geometry for easy accessibility to a patient. Preferably, the active planar shimming coil array has one or more pair of current loops arranged and constructed in a plane separating the open magnet structure from the remote region, a first loop having current in a first direction to provide a magnetic flux (i.e., magnetization vector) away from the plane and a second loop having current in the opposite direction to provide a magnetic flux (i.e., magnetization vector) toward the plane.

Planar open magnet MRI system having active target field shimming

A magnet resonance imaging system is described having an open solenoidal magnet structure that provides a remote region of background field homogeneity for imaging that is open and accessible. The system includes spatial encoding gradient coils and a rf coil. The open magnet structure has a pair of primary solenoidal coils and a bias coil system located within the primary coil geometry. The primary and bias coils emit a total additive flux in an imaging region to generate a resulting background magnetic field profile that provides a remote region of substantial field homogeneity with open geometry for easy accessibility to a patient.

Planar open solenoidal magnet MRI system

A magnet resonance imaging system is described having an open magnet structure that provides a remote region of background field homogeneity for imaging. The system includes spatial encoding gradient coils and an rf coil. The open magnet structure has a primary magnet with two primary pole pieces connected by a primary ferromagnetic core for internal flux. Each primary pole piece has a surface facing away from the primary magnet. Located between the two primary pole pieces is a bias magnet having two bias pole pieces connected by a bias ferromagnetic flux pathway for internal flux. The bias magnet has polarity opposite to the primary magnet. Each bias pole piece has a surface facing away from the bias magnet and in a direction the same as the surfaces of the primary pole pieces. Superposition of the magnetic fields of the primary magnet and bias magnet provide a region of substantial background field homogeneity remote from the magnets in said direction. Also described are (i) planar spatial encoding gradient coils that provide a remote gradient field in the region of substantial background field homogeneity and (ii) a planar rf coil that provides a remote rf field in the region of substantial background field homogeneity.

Planar open magnet MRI system

A magnetic resonance imaging (MRI) probe having an external background magnetic field B.sub.o is described. The probe has a primary magnet having a longitudinal axis and an external surface extending in the axial direction and a rf coil surrounding and proximal to the surface. The magnet provides a B.sub.o field having an external region of substantial homogeneity proximal to the surface. Preferably, the B.sub.o field is provided by two magnets spaced axially and in axial alignment and wherein said region of homogeneity intersects a plane located between the magnets and perpendicular to the axis. For MR imaging, surrounding the primary magnet are r-, z- and .o slashed.-gradient coils to provide spatial encoding fields.

MRI probe for external imaging

An MRI imaging device has a cylindrical magnet configuration, gradient coils and an Rf coil. The magnet has a primary and a secondary electromagnet on the same longitudinal center axis but spaced apart along the axis. Each electromagnet is a coil located within a flux guiding member preferably having a cylindrical structure closed at one end. The electromagnets provide a static magnetic field having substantial homogeneity in a central air gap A.sub.G extending from within the primary electromagnet coil axially beyond the primary coil toward the secondary electromagnet coil.

MRI device having high field strength cylindrical magnet with two

An MRI system has a magnet configuration that provides access for a surgeon or other personnel to perform procedures on a patient under support of real time MRI image. The magnet system uses a plurality of C-shape solenoidal magnets oriented to form an imaging volume in a central region of the magnets so that the magnetic flux from each magnet contributes to the magnetic field in the imaging volume. The configuration provides a high strength field in the imaging volume. The MRI system has a gradient coil for providing a magnetic field gradient in the imaging volume and an Rf coil for providing an Rf signal in the imaging volume. Preferably, the Rf coil also receives NMR signals from a specimen in the imaging volume.

MRI system having high field strength open access magnet

Apparatus and methods for performing MRI are disclosed wherein the encoding field has a multidimensional, preferably periodic, dependence. Two dimensional image information can be obtained without the necessity for switching the encoding field. Further, velocity information can be obtained. Preferred coil structures for providing preferred encoding fields are described.

Methods and apparatus for MRI

A magnet configuration particularly suited for MRI imaging in mammography is disclosed. The magnetic structure 50 has a rectangular shaped magnet with at least two parallel magnetic sources 5,6 connected by a ferromagnetic core flux path defining an air gap for imaging. A remote shimming C-shaped magnetic source is preferably used to decrease the front edge fringe effect of the magnetic structure 50 to create a relatively homogeneous field in the air gap beginning at the front edge for effective imaging.

High field strength magnet, preferably having remote shimming of field

A walker having wheels rotatably supported for orientation in any direction includes a flexible shaft for coupling rotation of the wheel to a tachogenerator in a supporting column that also carries an electronics cabinet including a relay that turns a tape recorder therein on when the wheel rotates, and off when the wheel is stationary. The electronics cabinet also includes a loudspeaker that reproduces the audible messages recorded on the tape recorder when the tape recorder is turned on.

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Revere, MA, United States of America

Yuly M Pulyer