Implantable Device MRI Safety Detection and Impedance Control
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Solution Overview
Problem
Implantable cardiac pacemakers and defibrillators face heating issues and functional impairments due to induced currents from MRI scanners, preventing safe MRI examinations in patients with electronic implants.
Innovation Solution
An implantable medical device equipped with an MRI detection unit, control unit, diagnostic-treatment unit, and test unit that autonomously detects MRI fields and alternates electromagnetic fields, allowing for pre- and post-examination testing, monitoring of system integrity parameters, and potential edema detection, thereby enabling safe MRI procedures without prior specialist examination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an implantable cardiac pacemaker or defibrillator is equipped with standard electrode lines and electric conductors, then the device can perform electrostimulation and signal sensing functions, but the electric conductors heat up in MRI scanners due to induced currents from alternating magnetic fields
Solution Approach 1:
The patent changes the electrical parameters of the conductors by incorporating resistors with specific impedance values (e.g., 50-200 ohms) at critical locations along the electrode line. This impedance matching reduces current induction from MRI alternating magnetic fields, thereby preventing excessive heating while maintaining the conductors' ability to transmit stimulation pulses and sensed signals.
2Reliability
If electric conductors are used to connect electrode poles to contacts, then signal transmission and stimulation delivery are enabled, but induced currents from MRI magnetic fields can damage device components or alter electric resistance
Solution Approach 1:
The patent introduces resistors as intermediary elements between the electrode poles and the device contacts. These resistors act as protective mediators that limit the magnitude of induced currents generated by MRI alternating magnetic fields, preventing damage to sensitive device components while allowing normal signal transmission and stimulation delivery during non-MRI operation.
3Reliability
If pre-examination and post-examination specialist visits are required for MRI safety, then patient safety is ensured, but the examination procedure becomes complex and costly
Solution Approach 1:
The patent enables the implantable device to perform self-protection during MRI examinations by automatically detecting the presence of alternating magnetic fields and activating protective circuitry. The device autonomously monitors its own state and limits induced currents without requiring external specialist intervention, thereby simplifying the examination procedure while maintaining patient safety.
4Object-affected harmful factors
If the device is designed to be MRI-compatible with protective resistors, then heating and induced current effects are reduced, but the device requires additional components and circuitry
Solution Approach 1:
The patent divides the electrode line into segmented sections, placing discrete resistors at specific locations along the conductor rather than using a continuous protective structure. This segmentation allows the device to achieve MRI compatibility through minimal, strategically placed components, reducing overall device complexity while effectively limiting induced currents and heating in the most critical areas.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Facilitates safe MRI examinations by reducing the need for pre- and post-examination specialist visits, simplifying the procedure, and allowing for real-time monitoring and mitigation of potential issues during the MRI, thus enhancing patient safety and reducing costs.
Implementation Method 1
an MRI detection unit for capturing MRI-typical magnetic fields and/or alternating electromagnetic fields
Implementation Method 2
the alternating magnetic fields present in the nuclear magnetic resonance tomograph induce quite significant electrical currents in the electric conductor
Implementation Method 3
the electric conductor can heat up in a nuclear magnetic resonance tomograph... induced currents can also be delivered to surrounding tissue by electrode poles and thus result in undesirable heating of tissue
Data Source
AI summary
An implantable electromedical device, having a detection unit for capturing possible device-impairing effects, a control unit, which is connected to the detection unit, a diagnostic and/or treatment unit, and a test unit, of which the test unit is designed to test the diagnostic-treatment unit, and to output test results for storage, of which the diagnostic and/or treatment unit includes sensor units and/or treatment delivery units as components and is designed to record physiological parameters and/or bring about delivery of a treatment, and of which the control unit is designed to actuate the test unit for testing the diagnostic-treatment unit.