Abstract: A coaxial cable may include an inner conductor, an outer conductor coaxially disposed about the inner conductor, and a proximal end sized and shaped for insertion into a connector. The proximal end may have an outer conductor contact coupled electrically to the outer conductor, and an extended section of the inner conductor that extends axially beyond the outer conductor contact. The extended section may include an inner conductor contact having an electrically conductive material disposed at least partially around the inner conductor, and an insulated area positioned to isolate electrically the outer conductive contact from the inner conductive contact, and having an electrically insulating material disposed at least partially around the inner conductor.

Abstract: A filtering scheme for an implantable medical device mitigates potentially adverse effects that may be caused by MRI-induced signals. In some aspects filtering is provided to attenuate MRI-induced signals on an implanted cardiac lead that is coupled to an implanted device. In some aspects the filter may be configured to complement a capacitor circuit (e.g., a feedthrough capacitor) that reduces the amount of EMI that enters the implanted device via the cardiac lead. In some implementations the filter consists of a LC tank circuit and a series LC circuit, where the LC tank circuit is in series with the cardiac lead and a cardiac stimulation circuit and the series LC circuit is in a shunt configuration across the cardiac stimulation circuit.

Abstract: An implantable medical lead is disclosed herein. In one embodiment, the lead includes a body and an electrical pathway. The body may include a distal portion with an electrode and a proximal portion with a lead connector end. The electrical pathway may extend between the electrode and lead connector end and include a coiled inductor including a first portion and a second portion at least partially magnetically decoupled from the first portion. The first portion may include a first configuration having a first SRF. The second portion may include a second configuration different from the first configuration. The second configuration may have a second SRF different from the first SRF. For example, the first SRF may be near 64 MHz and the second SRF may be near 128 MHz.

Abstract: An implantable lead is provided that comprises a lead body and a header assembly. The lead body has a distal end and a proximal end. The lead body is configured to be implanted in a patient. The header assembly is provided at the distal end of the lead body and includes an internal chamber and a tissue engaging end. An electrode is provided on the header assembly. The electrode is configured to deliver a stimulating pulse. A resonant inductor is located within the chamber in the header assembly. An electrically floating heat spreader is provided on the header assembly. The heat spreader is located proximate to the resonant inductor and is positioned on the header assembly to cover at least a portion of the resonant inductor. The heat spreader is thermally coupled to the resonant inductor to convey thermal energy away from the header assembly.

Abstract: An implantable lead is provided that includes a lead body configured to be implanted in a patient. The lead body has a distal end and a proximal end, and a lumen extending between the distal and proximal ends and includes a connector assembly provided at the proximal end of the lead body. The connector assembly is configured to connect to an implantable medical device and includes an electrode provided proximate to the distal end of the lead body with the electrode configured to at least one of deliver stimulating pulses and sense electrical activity. A multi-layer coil is located within the lumen and extends at least partially along a length of the lead body. The coil includes a first winding formed with multiple winding turns, the winding turns being segmented in an alternating pattern of insulated segments and non-insulated segments along the length of the lead body.

Abstract: An implantable medical lead configured to reduce resonant currents in a resonating circuit during MRI scans and a method of manufacturing the same are disclosed herein. The method of manufacturing includes providing a medical lead comprising an electrical pathway from a tip electrode located at a distal end of the lead to a lead connector located at a proximal end and coupling a resonating circuit to the tip electrode such that the resonating circuit is in the electrical pathway for the tip electrode. Further, the method includes coupling a capacitive element to a proximal end of the resonating circuit. The capacitive element is configured to shunt at least part of an RF current induced on the electrical pathway into surrounding tissue or fluid and also works as a heat sink to spread the heat from the internal LC resonant circuit.

Abstract: A radio frequency coil array (50) includes at least first (501) and second (502) receive coils. A flux pipe (52) includes electrically connected first (2521) and second (2522) loop coils. The first (2521) and second (2522) loop coils are coupled to the respective first and second receive coils. The flux pipe (52) reduces mutual inductance between the first (501) and second (502) receive coils.

Abstract: An apparatus for use in a magnetic resonance examination includes a radio frequency receive coil (50) and adjustable tuning circuitry (51) for adjusting the resonant frequency of the receive coil. The apparatus also includes a preamplifier (29) which amplifies signals generated by the receive coil. An adjustable feedback circuit (31) alters an effective Q of the receive coil.

Abstract: An implantable lead is provided that comprises a lead body extending along a longitudinal axis. The lead body includes a distal end and a proximal end and a lumen within the lead body. The lead also includes a header assembly provided at the distal end of the lead body. The header assembly includes a tissue engaging end. The lead also includes an electrode provided on the header assembly. The electrode is configured to deliver stimulating pulses. The lead also includes an electrode conductor provided within the lumen of the lead body and extending from the electrode to the proximal end of the lead body. An LC resonant component is provided in at least one of the lead body and the header assembly. The LC resonant component comprises a capacitor having an elongated shape that extends along the longitudinal axis of the lead body. The capacitor has a core that is located about the longitudinal axis of the lead body.

Abstract: A biocompatible inductor for an implantable medical lead is disclosed herein. In one embodiment the biocompatible inductor may include a biocompatible bobbin and a wire wound about a barrel of the biocompatible bobbin to form a coil. The wire may include an electrically conductive core, an electrically conductive biocompatible jacket extending over the core, and a coating of high dielectric strength insulation material extending over the jacket. Additionally, the biocompatible inductor may include medical adhesive located in gaps within the coil and a polyester shrink tube covering the coil.

Abstract: A filtering scheme for an implantable medical device mitigates potentially adverse effects that may be caused by MRI-induced signals. In some aspects filtering is provided to attenuate MRI-induced signals on an implanted cardiac lead that is coupled to an implanted device. In some aspects the filter may be configured to complement a capacitor circuit (e.g., a feedthrough capacitor) that reduces the amount of EMI that enters the implanted device via the cardiac lead. In some implementations the filter consists of a LC tank circuit and a series LC circuit, where the LC tank circuit is in series with the cardiac lead and a cardiac stimulation circuit and the series LC circuit is in a shunt configuration across the cardiac stimulation circuit.

Abstract: An implantable lead is provided that comprises a lead body and a header assembly. The lead body has a distal end and a proximal end. The lead body is configured to be implanted in a patient. The header assembly is provided at the distal end of the lead body and includes an internal chamber and a tissue engaging end. An electrode is provided on the header assembly. The electrode is configured to deliver a stimulating pulse. A resonant inductor is located within the chamber in the header assembly. An electrically floating heat spreader is provided on the header assembly. The heat spreader is located proximate to the resonant inductor and is positioned on the header assembly to cover at least a portion of the resonant inductor. The heat spreader is thermally coupled to the resonant inductor to convey thermal energy away from the header assembly.

Abstract: An implantable lead is provided that includes a lead body configured to be implanted in a patient. The lead body has a distal end and a proximal end, and a lumen extending between the distal and proximal ends and includes a connector assembly provided at the proximal end of the lead body. The connector assembly is configured to connect to an implantable medical device and includes an electrode provided proximate to the distal end of the lead body with the electrode configured to at least one of deliver stimulating pulses and sense electrical activity. A multi-layer coil is located within the lumen and extends at least partially along a length of the lead body. The coil includes a first winding formed with multiple winding turns, the winding turns being segmented in an alternating pattern of insulated segments and non-insulated segments along the length of the lead body.

Abstract: A conducting sheath is provided along at least a portion of an implantable medical device lead, and preferably along substantially its entire length, for mitigating heating problems arising during magnetic resonance imaging (MRI) procedures, particularly problems arising due to a problem described herein as the “coiling effect.” During device implant, the clinician may elect to wrap or coil excess proximal portions of leads around or under the medical device being implanted. Thereafter, during MRI procedures, shunt capacitance may develop between the housing of the implantable device and insulated coils within the proximal portions of the lead that are near the device, resulting in greater lead heating during the MRI. The conducting sheath helps suppress induced currents and also reduces or eliminates shunt capacitance. The conducting sheath may be, for example, formed using a metal mesh or a conducting polymer tube incorporating non-ferrous metal powders. The sheath may be formed in ¼ wavelength segments.

Abstract: An apparatus for use in a magnetic resonance examination includes a radio frequency receive coil (50) and adjustable tuning circuitry (51) for adjusting the resonant frequency of the receive coil. The apparatus also includes a preamplifier (29) which amplifies signals generated by the receive coil. An adjustable feedback circuit (31) alters an effective Q of the receive coil.

Abstract: A magnetic resonance imaging system includes a primary magnet and a secondary magnet operable to produce magnetic fields within a sample being imaged. The MRI system further includes at least one RF coil that is operable to receive electromagnetic frequencies from the sample. The RF coil is formed from tubing that serves as a cooling conduit through which flows a cooling fluid provided by a cooling source. The cooling fluid cools the RF coils to improve imaging of the sample.

Abstract: An implantable medical lead is disclosed herein. In one embodiment, the lead includes a body and an electrical pathway. The body may include a distal portion with an electrode and a proximal portion with a lead connector end. The electrical pathway may extend between the electrode and lead connector end and include a coiled inductor including a first portion and a second portion at least partially magnetically decoupled from the first portion. The first portion may include a first configuration having a first SRF. The second portion may include a second configuration different from the first configuration. The second configuration may have a second SRF different from the first SRF. For example, the first SRF may be near 64 MHz and the second SRF may be near 128 MHz.

Abstract: A radio frequency coil array (50) includes at least first (501) and second (502) receive coils. A flux pipe (52) includes electrically connected first (2521) and second (2522) loop coils. The first (2521) and second (2522) loop coils are coupled to the respective first and second receive coils. The flux pipe (52) reduces mutual inductance between the first (501) and second (502) receive coils.

Abstract: A magnetic resonance probe may include a plurality of center conductors, at least some center conductors including a conductive core and an insulator disposed at least partially about the core along at least a portion of the core, a first dielectric layer disposed at least partially about the plurality of center conductors in a proximal portion of the probe, an outer conductive layer at least partially disposed about the first dielectric layer, and a plurality of electrodes, at least one electrode being coupled to one of the center conductors and disposed at least partly on a probe surface.

Abstract: A magnetic resonance probe may include a plurality of center conductors, at least some center conductors including a conductive core and an insulator disposed at least partially about the core along at least a portion of the core, a first dielectric layer disposed at least partially about the plurality of center conductors in a proximal portion of the probe, an outer conductive layer at least partially disposed about the first dielectric layer, and a plurality of electrodes, at least one electrode being coupled to one of the center conductors and disposed at least partly on a probe surface.