Medrad, Inc.

Norland Corporation

General Electric Company

General Electric Corporation Gmbh

Kenneth W Belt

J Michael Watral

Michael Reichel

Stanley R Lewandowski

Robert S Bell, Jr

Bradley J Adams

Lisa A Augustine

Daniel Joseph Schaefer

Matthew G Eash

Phillip Edward Steen

Ralph S Hashoian

Yoon-Won Kang

Howard R Wagner

George L Congdon

John Edward Ferut

John S Mattson

Johnny E Parham, Iii

John A Wolak

An apparatus for enabling operation of adjacent coil loops with a magnetic resonance system. The apparatus includes a correction network interconnecting the coil loops for enabling both concurrent and separate operation of the coil loops. The correction network includes an input network for each coil loop and an isolation circuit. Each input network includes a balun and an active decoupling circuit for interconnecting the coil loop and balun. The balun links the input network to the MR system. The active decoupling circuits are capable of being (A) activated concurrently thereby disabling both loops during the transmit cycle, (B) deactivated concurrently thereby enabling each loop to receive MR signals during the receive cycle and (C) deactivated/activated separately thereby enabling either one but not both loops to receive MR signals during the receive cycle. The isolation circuit interconnects the loops for substantially canceling mutual inductance between them while they are enabled concurrently.

Apparatuses for enabling operation of adjacent coil loops with a magnetic resonance system

A circuit for selectively disabling and enabling n-coils includes n-drivers in a totem-pole configuration. Each of the n-drivers includes two transistors whose control terminals connect at a common node. Each n-driver is used to operate one of the n-coils by being responsive at its common node to (i) a coil disable signal by activating one transistor thereof and deactivating the other transistor thereof thereby drawing current away from and thus disabling its corresponding coil and allowing current to flow through the one transistor and thus be available as a source of current to a successive one of the n-drivers and (ii) a coil enable signal by deactivating the one transistor thereof and activating the other transistor thereof thereby allowing current to flow serially through its corresponding coil and the other transistor thus enabling its corresponding coil and to be available as a source of current to the successive n-driver.

Circuit for selectively enabling and disabling coils of a multi-coil array

A coil interface is capable of coupling an array of coils to a magnetic resonance (MR) system. The MR system is equipped with a predetermined number of receivers. The coil interface includes a plurality of input ports, a plurality of output ports, and an interface circuit disposed therebetween. The plurality of input ports is used to couple the interface circuit to the coils of the array. The plurality of output ports is used to couple the interface circuit to the receivers of the MR system. The interface circuit is used to selectively interconnect at least two of the input ports to at least one of the output ports, thereby allowing the array of coils to be selectively operated in any one of a plurality of operational modes.

Interface for coupling an array of coils to a magnetic resonance imaging system

An array of coils is configured for use in imaging the vasculature of a patient. The array of coils comprises first and second pluralities of coil pairs for deployment longitudinally along anterior and posterior surfaces, respectively, of the patient. In the first plurality, each coil pair has first and second loops positioned laterally about right and left sides, respectively, of the anterior surface for receiving therefrom magnetic resonance signals. In the second plurality, each coil pair has first and second loops positioned laterally about right and left sides, respectively, of the posterior surface for receiving therefrom magnetic resonance signals. Means are provided for laterally isolating the first and second loops relative to each other for each coil pair. Means are provided for longitudinally isolating the coil pairs relative to each other. Means also vertically isolate the coil pairs of the first plurality from those of the second plurality.

Array of coils for use in imaging the vasculature of a patient

A method is provided for imaging a vasculature of a patient using an MRI system with an array of local coils. The method includes thestep of providing a housig by which (I) a first plurality of the coils is arrayed along an anterior surface of the patient, (II) a second plurality of the coils is arrayed along a posterior surface of the patient, and (III) the patient is oriented such that portions of the vasculature between and including the renal and feet portions thereof are aligned substantially coplanarly. The method also includes the step of injecting a contrast agent into the patient. The method further involves acquiring images of the vasculature from approximately the renal portion thereof to an including the feet portion thereof so that the images of the portions of the vasculature are acquired successively in timed relation to a progression of the contrast agent therethrough.

Method of imaging a vasculature of a patient

An apparatus enables a patient to be positioned optimally for a scanning procedure during which images are to be obtained of the vasculature of the patient. The apparatus includes a lumbar support, a tray, and a leg support. The lumbar support allows the renal portion of the vasculature to be positioned predominately in a single plane. The tray allows the pelvic and femoral portions of the vasculature to be positioned substantially coplanar with each other and with the renal portion of the vasculature. The leg support allows the lower leg and feet portions of the vasculature to be positioned substantially coplanar with each other and with the pelvic and femoral portions of the vasculature. The substantial coplanar alignment of the portions of the vasculature enables the images thereof to be obtained with a smaller field of view and thus at least one of greater resolution and reduced scanning time.

Apparatus and method for positioning a patient to obtain images of the vasculature

A circuit for selectively disabling and enabling n-coils includes n-drivers disposed in a totem-pole configuration. Each of the n-drivers includes two FETs whose gates connect at a common node therefor. Each n-driver is used to operate one of the n-coils by being responsive at its common node to (i) a coil disable signal by activating one FET thereof and deactivating the other FET thereof drawing current away from and thus disabling its corresponding coil and allowing current to flow through the one FET and thus be available as a source of current to a successive one of the n-drivers and (ii) a coil enable signal by deactivating the one FET thereof and activating the other FET thereof thereby allowing current to flow serially through its corresponding coil and the other FET thus enabling its corresponding coil and to be available as a source of current to the successive n-driver.

An interface that couples a surface coil array having N receiving elements to an NMR scanner having M preamplifier inputs. The interface includes an RF switch array and a transmit/receive bias circuit. The RF switch array and the transmit/receive bias circuit are controlled by a control logic circuit. In response to a predetermined input, the control logic circuit causes a predetermined subset of the N receiving elements to be couple to the preamplifier inputs of the NMR scanner. Preferably, N may be larger than M.

Peripheral vascular array

A fixture for testing a magnetic resonance imaging system comprises a mounting plate for positioning the fixture within the system. The mounting plate has a plurality of apertures each of which being adapted to receive a test coil. The test coil includes a housing having a section that can fit within each mounting plate aperture and a receptor for holding a test substance. A coil with a plurality of turns of a conductor is located with the housing and an electrically conductive shield extends around the coil. One or more nestable spacer modules are provided to fit with a mounting plate aperture and receive the test coil to maintain the test coil a defined distance from the mounting plate.

Test apparatus for magnetic resonance imaging systems

A dual frequency NMR coil pair is comprised of two individual coils tuned to separate resonant frequencies. Each coil is formed into approximately the same shape by a conductive loop which follows a serpentine path to define an inner area and a plurality of outer lobes. The two individual coils are positioned in close proximity overlying each other, but rotated with respect to each other such that the outer lobes of the two respective coils are interleaved, i.e. not overlaying each other. As a result, mutual loading between the two individual coils is essentially eliminated, permitting dual frequency operation with minimal degradation of Q or signal-to-noise ratio (SNR) in either coil.

Dual frequency NMR surface coil pair with interleaved lobe areas

A radio frequency coil for use in MR imaging applications includes a series of conducting segments aligned with the longitudinal, static magnetic field of the MR magnet. A hybrid power splitter/combiner feeds each axial segment with a phased signal to generate a transverse circularly polarized magnetic field. The power splitter combiner isolates the axial segments to reduce magnetic field distortions produced by capacitive coupling between the imaged object and the radio frequency coil. The axial segments are tuned to series resonance to further reduce capacitive coupling. A stepped shield design permits separation of the power splitter combiner from the axial segments without piercing the bore tube.

Radio frequency field coil and power splitter for NMR

An apparatus and method are disclosed which provide signals corresponding to physiological motion of an imaging slice in an MR system for use in synchronizing acquisition of MR data with movement of the slice. The signals are generated by initiating an incident signal of a frequency .omega. which interacts with the imaging slice and returns a reflected signal of a frequency .omega.. By mixing the incident and reflected signal, a baseband signal is generated which is indicative of changes in the phase and magnitude relationships between the signals. Because changes in the phase and magnitude relationships between the signals are related in an approximately linear manner to movement of the imaging slice, the baseband signal provides an indication of movement of the imaging slice of sufficient quality to serve as an accurate triggering signal to synchronize acquistion of MR data with movement of the imaging slice.

Apparatus and method of acquiring physiological gating signals for

A battery powered external pacer operable in fixed-rate and demand modes includes a sense amplifier having an active notch filter system for attenuating power line interference. The filter system comprises four separate data channels each including a transmission gate synchronously driven by pacer clock pulses for frequency stability. Charges developed on capacitors in each data channel are summed by an output capacitor to avoid the need for amplifiers in each channel. A detector having two comparators for detecting positive and negative directed R-wave components derives heart pulses from the amplified signal. A pulse-driven reference supply having very low power consumption provides operating bias required by the detector. A battery monitor having a single comparator simultaneously monitors supply voltage for low and unusable voltage levels.

Cardiac pacer signal detector

Cardiac pacer having active notch filter system

A carrying case for a portable cardiac pacer having physician-actuable controls on the top and front panels of its housing includes a body portion having front, rear, side and bottom panels forming an open-ended enclosure in which the pacer is received. A first hinge-mounted flap extending across the open-end of the enclosure and a second hinge-mounted flap extending across the front panel of the body portion are secured at their free ends by a snap-fastener to the front panel of the body portion so as to retain the pacer securely seated within the enclosure. each of the flap panels includes a rigid portion overlying the associated panel controls of the pacer to prevent inadvertent actuation of the controls by pressure applied externally to the carrying case.

Growing community of inventors

Fort Atkinson, WI, United States of America

Kenneth W Belt