Neurological monitoring cable for magnetic resonance environments
Inventors
Kronberg, James W. • Floyd, Harrison • McCoy, Daniel E. • ORSINGER, Gabriel
Assignees
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Publication Number
US-11160483-B2
Publication Date
2021-11-02
Expiration Date
Abstract
An electrode system includes an electrode, a connector, and a cable with an in-line radio-frequency filter module comprising resistors and inductors without any deliberately added capacitance. The resistors are arranged in an alternating series of resistors and inductors, preferably with resistors at both outer ends, and connected electrically in series. The in-line module is located at a specific location along the wire, chosen through computer modeling and real-world testing for minimum transfer of received RF energy to a patient's skin, such as between 100 cm and 150 cm from the electrode end of a 240 centimeter cable. The total resistance of the resistors plus cable, connectors and solder is 1000 ohms or less; while the total inductance is roughly 1560 nanohenries. The inductors do not include ferrite or other magnetic material and are, together with the resistors, stock components thereby simplifying manufacture and reducing cost.
Core Innovation
A neurological monitoring device for magnetic resonance environments includes a neurological electrode configured to monitor neurological electrical signals, a connector operable to attach to an amplifier, and a cable having a first end and a second end. The first end is in electrical connection to the neurological electrode and the second end is in electrical connection to the connector. The cable includes an inline radio frequency filter module without lead wires.
The inline radio frequency filter module uses miniature, surface-mounted components including at least one resistor and at least one inductor in series with the at least one resistor. The module has no capacitors, and the inductor construction is ferrite-free with no ferrite or magnetic material.
The device is used in MRI radio frequency environments, where the module placement along the cable is described as optimized to minimize RF power delivered to the patient skin. The partial content further describes reductions in delivered skin RF power at 3T (128 MHz) and substantial reductions at higher frequencies such as 7T (about 299 MHz).
Claims Coverage
The partial content provides one independent claim covering a neurological monitoring device for magnetic resonance environments with an inline radio frequency filter module in the cable. Across the dependent claims referenced in the family summary, the coverage further refines resistor values, the physical contact arrangement of the inline module, housing material examples, and the arrangement and purpose of reducing and spreading resistive heating during a magnetic resonance procedure.
Neurological monitoring for magnetic resonance environments with inline RF filter module
A neurological monitoring device comprising a neurological electrode configured to monitor neurological electrical signals, a connector operable to attach to an amplifier, and a cable having first and second ends electrically connected to the electrode and the connector, the cable including an inline radio frequency filter module without lead wires, having miniature surface-mounted components including at least one resistor and at least one inductor in series with the at least one resistor, and without capacitors.
Inline series resistor within a defined resistance range
The device including at least one resistor with a total resistance between 1 and 1000 ohms.
Narrow inline series resistor resistance range
The device including at least one resistor whose total resistance is between 10 and 60 ohms.
Inline filter module end contacts
The device including an in-line filter module having a first end with a first contact and a second end with a second contact.
Nonconductive polymer outer housing materials for the inline module
The device including a nonconductive polymer selected from epoxy, silicone rubber, polyvinyl chloride, polyethylene, and polypropylene.
Resistor and inductor arrangement to reduce resistive heating during MRI
The device including selecting at least one resistor and at least one inductor by number, component value, and arrangement to reduce and spread resistive heating in a cable during a magnetic resonance procedure and thereby minimize resistance heating.
Overall claim coverage centers on a neurological monitoring device for magnetic resonance environments with a cable-embedded inline radio frequency filter module that uses miniature surface-mounted resistors and ferrite-free, lead-wire-free inductors arranged in series and excludes capacitors. Dependent coverage further specifies resistor resistance ranges, the inline module contact and end structure, nonconductive polymer housing examples, and component selection and arrangement intended to reduce and spread resistive heating during a magnetic resonance procedure.
Stated Advantages
Minimize RF power delivered to the patient skin.
Substantially reduce delivered skin RF power at higher frequencies, such as 7T, and reduce delivered skin RF power at 3T (128 MHz).
Reduce and spread resistive heating in a cable during a magnetic resonance procedure.
Minimize resistance heating.
Documented Applications
Neurological monitoring in magnetic resonance environments using a neurological electrode, cable, and connector with an inline radio frequency filter module.
MRI radio frequency environments at 3T (128 MHz) and higher frequencies such as 7T (about 299 MHz) to minimize RF power delivered to patient skin.
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