Picker International, Inc.

General Electric Company

Other

Ge Medical Systems Global Technology Company, LLC

Philips Medical Systems (cleveland), Inc.

Labros S Petropoulos

Michael Andrew Morich

Joseph Murphy-Boesch

Mark Xueming Zou

Hiroyuki Fujita

John Lester Patrick

Pei Hsuon Chan

Dashen Chu

Robert W Brown

David A Lampman

Mark A Richard

Heidi A Schlitt

Junxiao Ling

Gordon D DeMeester

Shmaryu M Shvartsman

Michael R Thompson

Dan Kenrick Spence

Nicholas J Mastandrea, Jr

Michael A Martens

Clarence E Payton

A S Hall

Rony Thomas

J V Hajnal

Yun-Jeong Yang

Shmaryu Shvartsman

Keith Richmond

A partially parallel acquisition RF coil array for imaging a sample includes at least a first, a second and a third coil adapted to be arranged circumambiently about the sample and to provide both contrast data and spatial phase encoding data.

Coil arrays for parallel imaging in magnetic resonance imaging

A MRI array coil includes a plurality of first coils in a receive coil array and a plurality of second coils in a transmit coil array. The receive coil array and the transmit coil array are electrically disjoint.

Integrated and independently controlled transmit only and receive only coil arrays for magnetic resonance systems

A partially parallel acquisition RF coil array for imaging a human head includes at least a first, a second and a third loop coil adapted to be arranged circumambiently about the lower portion of the head; and at least a forth, a fifth and a sixth coil adapted to be conformably arranged about the summit of the head. A partially parallel acquisition RF coil array for imaging a human head includes at least a first, a second, a third and a fourth loop coil adapted to be arranged circumambiently about the lower portion of the head; and at least a first and a second Figure-8 or saddle coil adapted to be conformably arranged about the summit of the head.

Head coil arrays for parallel imaging in magnetic resonance imaging

A partially parallel acquisition RF coil array for imaging a human head having a summit and a lower portion includes at least a first, a second and a third quadrature coil pair adapted to be arranged circumambiently about the lower portion of the head; and at least a forth, a fifth and a sixth quadrature coil pair adapted to be conformably arranged about the summit of the head.

Head RF quadrature coil array for parallel imaging

A MRI coil having an axis and a first end and an opposite second end with respect to said axis includes a first ring element at the first end, a second ring element, a third ring element, a fourth ring element at the second end where the first ring element encompasses a smaller area than each of the second, third, and fourth ring elements. The coil also includes a plurality of axial elements connected between the first, second, third and fourth ring elements. The third and fourth ring elements are axially closer than the first and second ring elements.

Asymmetric ring dome radio frequency coil

A MRI gradient coil set includes a uniplanar Z-gradient coil, a biplanar X-gradient coil, and a biplanar Y-gradient coil. The coil set provides an open Z-axis face.

Open architecture gradient coil set for magnetic resonance imaging apparatus

A magnetic resonance apparatus includes a main magnet ( ) which generates a main magnetic field through and surrounding an examination region ( ). The main magnetic field contains inhomogeneities which affect image quality. A gradient coil assembly ( ) generates gradient magnetic fields across the examination region, which contain higher order harmonics causing inhomogeneities in the gradient magnetic field. A multi-axis shim set ( ) is selectively excited in order to cancel both the main magnetic and gradient magnetic field inhomogeneities. More particularly, DC currents are applied by a shim coil power supply ( ) to cancel the main magnetic field inhomogeneities. AC current pulses are superimposed on the DC currents by the shim coil power supply ( ) in order to correct the gradient magnetic field inhomogeneities. The existence of correctable higher order gradient magnetic field harmonics provides for fast switching, high duty cycles, and high peak gradients, without adding distortions to the resulting magnetic resonance images.

Real-time multi-axis gradient distortion correction using an interactive shim set

A gradient coil assembly (,) generates substantially linear magnetic gradients across the central portion of an examination region (,). The gradient coil assembly (,) includes primary x, y, and z-gradient coils (,) which generate a gradient magnetic field (,) having a non-zero first derivative in and adjacent the examination region. Preferably, the gradient coil assembly (,) includes secondary, shielding x, y, and z coils which generate a magnetic field which substantially cancels, in an area outside a region defined by the shielding coils, a fringe magnetic field generated by the primary gradient coils. The existence of a non-zero first derivative in and adjacent the examination region eliminates aliasing effects attributable to the non-unique gradient field values on either side of a rollover point (,). The non-unique values of the gradient magnetic field adjacent the rollover point caused structure near the rollover point to overlay each other (FIGS.,B,,B). The unique non-linearity of the present gradient (,) adjacent the edges expands (magnifies) the image adjacent the edges (FIGS.,A,,A). Because the expansion is unique, distortions at the edges are readily and accurately mapped (,) back to linear.

Gradient coil set with non-zero first gradient field vector derivative

A uniplanar gradient coil assembly (,) generates substantially linear gradient magnetic fields through an examination region (,). The gradient coil assembly (,) includes at least a pair of primary uniplanar gradient coil sets (,) and a pair of shield coil sets (,) which are disposed in an overlapping relationship. One gradient coil set is displaced relative to the other gradient coil set such that the mutual inductance between the two is minimized. Preferably, the coil sets (,) are symmetric, such that the sweet spot of each coil is coincident with the geometric center of each coil. One primary uniplanar gradient coil set (,) is a high efficiency, high switching speed coil to enhance performance of ultrafast magnetic resonance sequences, while the second primary uniplanar gradient coil set (,) is a low efficiency coil which generates a high quality gradient magnetic field, but with slower switching speeds. By displacing one gradient coil set relative to the other, mutual inductance is minimized, which maximizes peak gradient, rise time, and slew rate, while dB/dt levels are minimized. In one embodiment, the uniplanar gradient coil assembly (,) is housed within an interior of a couch (,).

Phased array planar gradient coil set for MRI systems

Methods of designing an active shield for substantially zeroing an electro-magnetic field on one side of a predetermined boundary in open magnetic resonance imaging systems and in open electric systems are provided. The methods include defining a finite length geometry for a primary structure which, in the case of zeroing a magnetic field, carries a first current distribution on its surface. A finite length geometry is also defined for a secondary structure which, in the case of zeroing a magnetic field, carries a second current distribution on its surface. In the case of zeroing an electric field, the current distributions are replaced with charge distributions. A total magnetic or electric field resulting from a combination of the first and second current or charge distributions respectively is constrained such that normal components (in the magnetic field case) or tangential components (in the electric field case) thereof substantially vanish at the surface of one of the primary and secondary structures. The first current or charge distribution is constrained to the surface of the primary structure, and the second current or charge distribution is constrained to the surface of the secondary structure. The first and second current or charge distributions are then calculated concurrently allowing both the first and second current or charge distributions to vary while observing the constraints such that a predetermined magnetic or electric field is achieved in a first region and a magnetic or electric field on one side of a predetermined boundary is substantially zeroed.

Super shielding of finite length structures in open magnetic and electric systems

A method of designing a shielded gradient coil assemblies (22) for magnetic resonance imaging systems is provided. The method includes generating a first continuous current distribution for a primary coil (60) using an inverse approach. The first continuous current distribution is confined within predetermined finite geometric boundaries of a surface defined by two dimensions and generates a magnetic gradient field across an imaging region (14). The magnetic gradient field constrained to predetermined values at specified spatial locations within the imaging region (14). The current distribution and magnetic field are converted into a stored energy and magnetic field domain where a finite element analysis is performed to generate a second continuous current distribution for a shielding coil (62). The second continuous current distribution is confined within predetermined finite geometric boundaries of a surface surrounding the primary coil (60). The second continuous current distribution generates a magnetic field which substantially cancels in an area outside a region defined by the shielding coil a fringe magnetic field generated by the first continuous current density.

Gradient coil set with a finite shield current

A method of designing a shielded gradient coil assemblies (22) with a flared primary coil (60) for magnetic resonance imaging systems is provided. The method includes generating a first continuous current distribution for a primary coil (60) using an inverse approach. The first continuous current distribution is confined within predetermined finite geometric boundaries of a surface defined by three dimensions and generates a magnetic gradient field across an imaging region (14). The magnetic gradient field is constrained to predetermined values at specified spatial locations within the imaging region (14). The current distribution and magnetic field are converted into a stored energy and magnetic field domain where a finite element analysis is performed to generate a second continuous current distribution for a shielding coil (62). The second continuous current distribution is confined within predetermined finite geometric boundaries of a surface surrounding the primary coil (60). The second continuous current distribution generates a magnetic field which substantially cancels in an area outside a region defined by the shielding coil a fringe magnetic field generated by the first continuous current density.

Flared gradient coil set with a finite shield current

A method of designing a shielded gradient coil assembly (22) for magnetic resonance imaging systems is provided. The gradient coil structure comprises two sets of primary gradient coils (60, 62) and a single set of a shielded (screening) coils (64). This configuration is suitable for MR applications utilizing a double duty gradient configuration including a high-efficiency primary coil set that enhances the performance of ultra fast MR sequencing while minimizing the dB/dt and eddy current effects, and including a low-efficiency primary coil set having a high-quality gradient field that is suitable for conventional imaging applications with inherently low dB/dt and eddy current levels. In addition, a minimum inductance/energy algorithm assists in the design of the two primary and the one secondary gradient sets.

Double-duty gradient coil assembly having two primary gradient coil sets

A superconducting magnetic imaging apparatus includes a vacuum vessel (16) having a central helium reservoir (20) in which superconducting magnetic coil windings (12) are maintained at a superconducting temperature. The vacuum vessel defines an internal bore (22) within which a self-shielded gradient coil assembly (26) and an RF coil (30) are received. The self-shielded coil assembly includes a single former (50) which defines an imaging region (14) within which an imaged portion of a subject is received. Primary x, y, and z-gradient coils (72-76) are positioned over an RF ground screen (70) that is bonded to the former (50). A number of comb-like spacers (84) extend from the former to supporting shield x, y, and z-gradient coils (110-114). The comb-like spacers define passages between the primary and secondary gradient coils which receive inner and outer cooling tubes (90, 92) and shim tray molds (108). The fully assembled gradient coil assembly is potted to form a unitary structure in a single potting step. The shim tray molds are subsequently removed to define channels or pockets suitable for receiving shim trays (118).

Self-shielded gradient coil assembly and method of manufacturing the same

A magnetic resonance imaging apparatus (10) has a main magnet having a pair of pole faces (16,18) defining an examination region (14). The main magnet generates a main magnetic field (12). A couch (30) suspends a subject within the examination region (14). A uniplanar gradient coil assembly (40) is positioned to one side of the subject. The uniplanar gradient coil assembly (40) generates magnetic field gradients across the examination region (14). The uniplanar gradient coil assembly (40) includes coil loop arrays each residing in a plane which is transverse to the main magnetic field (12). A current supply (42) supplies a electrical current pulses to the coil loop arrays. A radio frequency pulse generator (50) is employed for selectively exciting magnetic resonance of dipoles within the examination region (14). A receiver (54) receives magnetic resonance signals from the resonating dipoles and a reconstruction processor (62) forms an image representation from the magnetic resonance signals received. In one embodiment, the uniplanar gradient coil assembly (40) is housed within an interior of the couch (30) and a mechanical adjustment mechanism (70) adjusts the height of the uniplanar gradient coil assembly (40) to align the magnetic gradient region having optimum linearity with an area of interest of the subject.

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Solon, OH, United States of America

Labros S Petropoulos