Abstract: A phased array for a magnetic resonance (MR) imaging apparatus is disclosed that includes a plurality of receiver coils arranged to form a staggered hexagonal coil array, with the staggered hexagonal coil array being rectangular in shape. Included in the plurality of receiver coils are a plurality of standard coils and a plurality of filler coils differing in shape from the standard coils. The shape of the filler coils is such that no more than negligible mutual inductance between the filler coils and all adjacent overlapping standard coils is present.

Abstract: A phased array for a magnetic resonance (MR) imaging apparatus is disclosed that includes a plurality of receiver coils arranged to form a staggered hexagonal coil array, with the staggered hexagonal coil array being rectangular in shape. Included in the plurality of receiver coils are a plurality of standard coils and a plurality of filler coils differing in shape from the standard coils. The shape of the filler coils is such that no more than negligible mutual inductance between the filler coils and all adjacent overlapping standard coils is present.

Abstract: An RF coil assembly includes a plurality of coil supports rotatably interconnected to each other. Each coil support is configured to rotate with respect to at least one adjoining coil support. A plurality of RF coils is connected to each coil support.

Abstract: An RF coil assembly includes a plurality of coil supports rotatably interconnected to each other. Each coil support is configured to rotate with respect to at least one adjoining coil support. A plurality of RF coils is connected to each coil support.

Abstract: A positioner for a magnetic resonance (MR) surgery system which positions a focal point of an ultrasound transducer to selectively destroys tissue in a region within a patient. The positioning means moves an ultrasound transducer under the control of an operator. Mechanical threaded shafts and slides act as screw drives causing several connected slides to move the ultrasound transducer in three dimensions. Expanding shafts are connected between a fixed point on a housing and the actuating point of the threaded shafts. Two of the expanding shafts employ universal joints allowing the shafts to rotate as they follow the slides. The third expanding shaft need only expand but the relative angle between its attachment points does not change, thereby eliminating the need for universal joints.

Abstract: A magnetic field gradient apparatus for use in a magnetic resonance (MR) imaging system employing open magnets allows access to a patient while the patient is being imaged. The magnetic field gradient apparatus employs two gradient coil assemblies and a gradient coil amplifier. Each gradient coil assembly has a gradient coil carrier with at least one gradient coil disposed on it. Each gradient coil carrier is comprised of a cylinder with a flange at one end. The gradient coil assemblies are positioned in the bore of each ring of the open magnet and spaced apart from each other allowing access to the patient. The gradient coil amplifier provides current through the gradient coils to create a magnetic field gradient which has high linearity inside an imaging volume. A coil is disposed on cylinders which surround each gradient coil assembly and fit inside the bore of each ring which acts as an active shield and minimizing eddy currents in conductors outside the gradient coil assemblies.

Abstract: Invasive devices, such as laser fiber guides and biopsy needles, constructed of a material which exhibits little or no magnetic susceptibility, have a flexible polymer coating for retaining pieces of the device in the event of a fracture of the invasive device. The polymer coating also allows removal of the pieces of a fractured invasive device from the body of a subject without requiring surgery. The surgical instruments can be used inside a magnetic field during magnetic resonance (MR) imaging, thereby allowing interactive internal images to be produced and displayed to a surgeon during surgery. Since the invasive devices exhibit low susceptibility, they do not distort a created MR image.

Abstract: A magnetic resonance (MR) surgery system facilitates surgery with a focussed ultrasound transducer that selectively destroys tissue in a region within a subject. The focussed energy transducer dissipates energy at a focal point within the region of tissue to be destroyed. A non-magnetic positioning device having a vertical dimension small enough to fit easily within the bore of an MR magnet moves an energy transducer in a limited vertical space. The positioning device employs a plurality of hydraulic positioners and an inclined plane to position the ultrasound focal point under the control of an operator. An MR imaging system employing a temperature sensitive pulse sequence creates an image of the tissue and the region being heated to allow the operator to adjust the position of the ultrasonic transducer so as to direct ultrasonic energy to the appropriate location.

Abstract: A magnetic resonance surgery system facilitates performance of surgery with a focussed ultrasound transducer that selectively destroys tissue in a region within a subject. The focussed ultrasound transducer dissipates ultrasonic energy at a focal point within the region of tissue to be destroyed. A number of hydraulic positioners position the focal point under the control of a surgeon. A magnetic resonance imaging system employing a temperature sensitive pulse sequence creates an image of the tissue and the region being heated to allow the surgeon to adjust the position of the ultrasonic transducer so as to direct ultrasonic energy to the appropriate location.

Abstract: An analog to digital converter circuit includes encoder circuitry which employs a dummy bit line to derive timing signals employed in establishing stable, valid output digital signal information. For almost all binary codes of interest, the dummy bit line employed may actually comprise a portion of an otherwise unused bit line. The present invention is also distinguished in that it employs a clocked regenerative bit line sustainer circuit driven by dummy bit line derived timing signals. Additionally, the present invention also preferably employs a folded antiparallel architecture in which the bit lines are disposed in a generally U-shaped surrounding the parallel segments along their outer edges.