General Electric Company

National Research Development Corporation

Other

Ge Medical Systems Global Technology Company, LLC

Invivo Corporation

Mrscience LLC

William A Edelstein

Paul Arthur Bottomley

Peter B Roemer

Otward M Mueller

Sayed-Amr A El-Hamamsy

John R Mallard

James M Hutchison

Robert Arvin Hedeen

John F Schenck

Thomas W Redpath

Glyn Johnson

Charles L Dumoulin

Ronald Dean Watkins

Rowland W Redington

Icko Eric Iben

Lowell Scott Smith

Robert L Brown

Eddy Benjamin Boskamp

Robert Adolph Ackermann

Scott Thomas Mansell

Cecil E Hayes

William Macomber Leue

Tesfaye Kebede Kidane

Richard Philip Mallozzi

Timothy P Eagan

Steven G Karr

Tanvir Baig

Richard Blair Sheldon

Victor Taracilla

Harold J Vinegar

Jerome Johnson Tiemann

Christopher Judson Hardy

Matthew N O'Donnell

Kenneth Gordon Herd

Paul Shadforth Thompson

Egidijus Edward Uzgiris

William D Barber

Robert Michael Vavrek

David E Dean

Mark Lloyd Miller

Michael J Radziun

Bruce Campbell Amm

Howard Roscoe Hart, Jr

Anthony Mantone

Frederic Ghislain Pla

Thomas Gerard Ebben

G Randy Duensing

John Andrew Mallick

Peter Ping-Liang Sue

Chia-Fu Hsu

Randy Otto John Giaquinto

Moayyed A Hussain

Matthew G Eash

Ray Fli Lee

Dewain Anthony Purgill

Jish M Wang

John Peter Fura

Raymond J Hodsoll, Jr

David R Eisner

Kemakolam Michael Obasih

Robert J Sutherland

Mike James Radziun

Philip Trefor Jones

David Keren

Benjamin Assif

Robert James Dobberstein

Nissim Ben Hamo

Frederick Schenck

Bernard Roemer

Andrew Phillip Shapiro

Icko Eric Timothy Iben

Qun Zhao

Hu Cheng

Icko T Iben

Gary Roland Brown

Carl Richard Scatena

William Bennett Silverstein

Scott Robert Blaha

The present invention provides an apparatus for reducing acoustic noise in a magnetic resonance imaging device including passive shielding located outside the actively shielded gradient winding elements in order to reduce the magnitude of fields that spread outside the gradient coil assembly in unwanted directions and interact with the magnet cryostat or other metallic magnet parts, inducing eddy currents that cause consequent acoustic noise. The passive shielding elements are conducting layers located on the outer radius of the cylindrical gradient coil assembly in a cylindrical magnet system, conducting layers located at the ends of the gradient coil assembly in a cylindrical magnet system, and conducting layers located inside the actively shielded gradient winding inner elements in a cylindrical magnet system. The passive shielding could also be located on separate structures that are vibrationally isolated from the magnet cryostat. The actively shielded gradient winding can also be extended to portions at the ends of the actively shielded gradient winding and further to portions inside the inner radius of the inner portion of the actively shielded gradient winding. The actively shielded gradient windings and passive shielding should be designed concurrently in order to substantially optimize the gradient linearity and reduce the eddy currents generated in metallic parts of the magnetic resonance imaging system.

Active-passive electromagnetic shielding to reduce MRI acoustic noise

The subject invention relates to a method and apparatus for producing stimulated MRI data. In an embodiment, a remote-controlled 'smart phantom' can produce simulated data. The simulated data can be acquired from a MRI system. The subject device can generate control signals and send the generated control signals to secondary coils/probes placed in the subject smart phantom. The control signals determine the current flow in the secondary coils/probes, which act as local spin magnetization amplifiers and thus produce regions of variable contrast to noise ratio. The control signals can be generated with various parameters, such as BOLD models, different levels of contrast-to-noise ratio (CNR), signal intensities, and physiological signals. Comparisons can be made with the widely-used simulated data by computers. Validation of the subject smart phantom can be performed with both theoretical analysis and data of human subjects.

Phantom for production of controllable fMRI signal

The present invention provides an apparatus for reducing acoustic noise in a magnetic resonance imaging device including a suspension element including at least one resilient element and an active drivable element for applying a compensating force to reduce vibration transmission. The active drivable element is positioned so as to not directly support the weight of the gradient coil assembly, which avoids applying strong forces to relatively fragile active drivable elements, such as piezoelectric force transducers. Force signals for the active drivable element are derived in a feed-forward manner from the applied gradient waveform or from motion of the gradient coil assembly bracket. Alternatively, the active drivable element can be driven by signals derived from measured vibration or other motion of parts of the MRI magnet, gradient coils or rf coils.

Active vibration compensation for MRI gradient coil support to reduce acoustic noise in MRI scanners

A radio frequency (RF) detector array and a MRI system are provided. The detector array comprises a plurality of conductive array elements being substantially parallel to a conductive ground plane, a plurality of capacitors, wherein at least one capacitor is shunted from each array element to the ground plane to adjust a corresponding electrical length of each conductive array element, and, wherein a combination of each respective array element, at least one corresponding capacitor and the ground plane forms a resonator that resonates at a selected frequency. The detector array further a decoupling interface, and a plurality of matching boxes for matching each decoupled conductive strip to a selected impedance. A MRI system is provided including a detector array as described herein to produce MR images of the object to be imaged.

RF detector array for magnetic resonance imaging

A technique is disclosed for shielding rf magnetic fields in MRI systems. An rf shield is embedded in a gradient coil structure including X-, Y- and Z-axis coils. The rf shield is positioned between an inner gradient coil which is inherently decoupled from the rf field, and the remaining coils which require rf shielding. The inner gradient coil may be a Z-axis coil wound as a solenoid, the field of which is generally orthogonal with respect to the rf magnetic field. The rf shield is thereby placed at an enhanced distance from the rf coil, providing greater efficiency and permitting energy levels to be reduced to obtain the desired rf magnetic field strength.

rf shielding method and apparatus

A rotating body coil assembly for use with an open MR magnet for imaging at least a portion of a subject comprises a resonant structure configured to rotate about the subject and to permit access to the subject during imaging. The body coil assembly comprises first and second end ring assemblies positioned on opposing sides of the imaging space. The first and second end ring assemblies are each configured to energize the body coil assembly. A plurality of element assemblies are disposed between and connecting the first and second end ring assemblies for providing structural support and electrical isolation of the body coil assembly. A base assembly is coupled to the first and second end ring assemblies and at least one of the element assemblies. The base assembly is adapted to rotate the first and second end ring assemblies in cooperation with the plurality of element assemblies about the portion of the subject while the portion of the subject is inside the imaging space for permitting access to the subject during imaging.

Rotating body coil apparatus for interventional magnetic resonance imaging

A self-shielded gradient coil assembly for an MR imaging system has inner and outer gradient coil windings disposed in coaxial relationship and defining a hollow annular space therebetween. Inner and outer helical cooling tubes are affixed to the outer and inner surfaces of the inner and outer gradient coil windings, respectively, by a thermally conductive epoxy, and a concrete filler material substantially fills the remaining hollow annular space. The concrete filler material may be poured into the hollow annular space to fill the space, or a pre-formed hollow concrete cylinder may be inserted coaxially into the space, defining remaining inner and outer annular volumes which are then filled with a thermally conductive epoxy bonding together the inner and outer gradient coil windings, the cooling tubes and the hollow concrete cylinder.

Filler material for magnet resonant system self-shielded gradient coil assemblies

A low noise imaging apparatus for producing Magnetic Resonance (MR) images of a subject and for substantially minimizing acoustic noise generated during imaging is provided. The imaging apparatus comprises a magnet assembly, a gradient coil assembly, and a rf coil assembly, wherein at least one of the magnet assembly, the gradient coil assembly and the rf coil assembly are configured to reduce the generation and transmission of acoustic noise.

Low noise MRI scanner

A quadrature coil suitable for use with an open frame MRI system provides crossing pairs of arrays of parallel conductor elements, respectively. Compact configuration is provided through use of an isolating circuit for incorporating parasitic capacitances at the resonance frequency of the coil into a blocking parallel resonance. Termination of the parallel conductor elements may be accomplished by equal impedance node connectors formed from branching pairs of conductors or a triangular least resistance connection form. RF shields are provided by pairs of conductive sheets containing eddy current reducing slots aligned with the parallel conductors elements of the coil.

Radio frequency coil for open magnetic resonance imaging system

Accurate sensing of ice readiness in an ice maker is accomplished using, as an ice readiness sensor, a capacitance bridge circuit having a first capacitor connected as a first bridge arm a second capacitor connected as a second bridge arm, a tunable capacitor connected as a third bridge arm and a probe connected as a fourth bridge arm. The probe includes a pair of electrode strips placed in close proximity to the belt of a belt ice maker. First and second bridge arms are connected at a first bridge node first and third bridge arms are connected at a second bridge node, second and fourth bridge arms are connected at a third bridge node, and third and fourth bridge arms are connected at a grounded fourth bridge node. The first and fourth bridge nodes are input terminals for receiving an AC drive signal from an AC source, and the second and third bridge nodes are output terminals. A signal processor, coupled to the second and third bridge nodes, includes an amplifier having its output coupled to a rectifier, and an output filter capacitor coupled to the rectifier. An output signal from the signal processor is supplied to a controller which controls the movement of the belt.

Methods and apparatus for detecting ice readiness

A sweep generator,applies a range of frequencies to an rf coil,to detect the resonant frequency of a field generated by a magnet,. A frequency to current converter,applies an auxiliary magnetic field to tune an MRI apparatus to the resonant frequency of the rf coil. A flexible coil of one turn (,) or two or more turns (,) has a plurality of segments (,). One of the belt has a contact k,, (k,&prime;), which is electrically connectable to one or more contacts k,, (k,&prime;), k,, (k,&prime;), etc. located between the ends of the segments. For each connection to successive contacts, the length of the coil and its inductance increases by the added impedance DL,between contacts k,and k,. That increase of inductance is nullified by capacitors DC,located between segments.

Method to automatically tune MRI RF coils

An MR magnet assembly includes a cylindrical vessel for housing a superconducting magnet and having a vacuum between its inner and outer walls. The vessel defines a magnet bore for receiving a patient to be imaged. A gradient coil assembly is mounted in the bore adjacent the inner wall of the magnet assembly. To reduce gradient coil noise, the inner wall is constructed of a non-conductive material which does not support eddy currents.

MRI magnet assembly with non-conductive inner wall

A sweep generator 230 applies a range of frequencies to an rf coil 140 to detect the resonant frequency of a field generated by a magnet 125a,b. A frequency to current converter 220 applies an auxiliary magnetic field to tune an MRI apparatus to the resonant frequency of the rf coil. A flexible coil of one turn (300) or two or more turns (500) has a plurality of segments (301-307; 501-513). One of the belt has a contact k0, (k0'), which is electrically connectable to one or more contacts k1, (k1'), k2, (k2'), etc. located between the ends of the segments. For each connection to successive contacts, the length of the coil and its inductance increases by the added impedance .DELTA.L.sub.ij between contacts k.sub.i and k.sub.j. That increase of inductance is nullified by capacitors .DELTA.C.sub.sij located between segments.

An in-situ method for thermal desorption, extraction, and destruction of dense nonaqueous organic contaminants in fractured bedrock is accomplished through the use of thermal wells, a flameless oxidizer, and hot carbon adsorption chambers.

Thermal desorption and destruction of dense non-aqueous phase liquid in

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Schenectady, NY, United States of America

William A Edelstein