Medrad, Inc.

J Michael Watral

Kenneth W Belt

Michael Reichel

Stanley R Lewandowski

Bradley J Adams

Lisa A Augustine

Robert S Bell, Jr

George J Misic

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

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 method of imaging a subject in an imaging system having a magnetic field and a plurality of receive coils movable with respect to the magnetic field includes sensing the magnetic field by means of at least one sensor having a known position with respect to the subject. At least one of the plurality of receive coils is selected in accordance with the sensing, and is enabled to form an image of the subject. The sensor may include a plurality of sensor coils disposed at differing locations within the magnetic field to sense the differing field amplitudes and/or phases thereof. The differing field intensities cause differing voltage amplitudes and/or phases to be induced on the sensor coils. The differing voltage amplitudes and/or phases are compared to determine the relative positions of the magnetic isocenter of the system and the receive coils to be enabled. Thus, a method for magnetic resonance imaging of a subject in an imaging system having a static magnetic field &lsqb;B,&rsqb;, a selectively applied gradient magnetic field &lsqb;B,&rsqb;, a selectively applied transmit excitation radio frequency magnetic field &lsqb;RF B,&rsqb;, and a plurality of simultaneous data acquisition channels is taught wherein the location of a phased array or other multiple element receive coil and the subject patient with respect to the imaging center of the host magnetic resonance imaging system is determined by sensing the characteristics of one of the magnetic fields.

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Freeport, PA, United States of America

J Michael Watral