MRI-Implantable Device Antenna Switch Isolation
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Solution Overview
Problem
Implantable medical devices (IMDs) face risks of tissue damage and device malfunction due to induced voltages and currents from electromagnetic radiation, particularly during MRI scans, as existing shielding methods are inadequate for higher energy density scans, and manual safe mode activation can be forgotten or fail.
Innovation Solution
Incorporating antennas that generate control signals in response to electromagnetic radiation to switch between conductive and non-conductive states, isolating lead wires from electrodes and IPG electronics, ensuring safe operation during MRI exposure and automatic reconfiguration post-exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electromagnetic shielding is used to protect lead wires from induced voltages and currents, then tissue damage is prevented, but the shielding becomes inadequate for higher energy density MRI scans
Solution Approach 1:
The switch is configured to automatically enter a non-conductive state in response to detecting electromagnetic radiation from an MRI device, thereby preemptively blocking induced voltages and currents before they can cause tissue damage. This automatic preliminary action ensures protection against both current and future higher energy density MRI scans without requiring manual intervention or complex shielding materials.
2Object-affected harmful factors
If manual safe mode activation is implemented, then device malfunction is prevented, but the mode can be forgotten or fail to activate
Solution Approach 1:
The IMD system performs self-protection by automatically detecting the presence of an MRI device through its antenna and switching to a non-conductive state without requiring manual activation. The system monitors electromagnetic radiation levels and autonomously prevents device malfunction, eliminating human error in safe mode activation while maintaining full functionality when MRI devices are absent.
3Object-affected harmful factors
If lead wires are electrically isolated during MRI exposure, then safety is enhanced, but therapeutic functionality is interrupted
Solution Approach 1:
The switch automatically transitions between conductive and non-conductive states based on the periodic presence or absence of MRI device electromagnetic radiation. During MRI scans, the system enters a non-conductive safe state; when MRI devices are absent, the system returns to a conductive therapeutic state. This periodic automatic switching ensures both safety during exposure and continuous therapeutic functionality during normal operation.
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
Prevents tissue damage and IPG malfunction by isolating induced voltages and currents, ensuring continuous therapeutic functionality and enhanced safety without compromising operational integrity, even with higher energy MRI scans.
Implementation Method 1
an antenna configured to generate a control signal in response to excitation of the antenna by a MRI device
Implementation Method 2
a switch electrically coupled to the antenna and configured to electrically isolate the electrode from the lead wire in response to the control signal
Data Source
AI summary
One or more antennas are electrically coupled to one or more switches of an implantable medical device (IMD) in which the one or more switches are additionally electrically coupled to one or more lead wires of an IMD lead. The one or more switches also are electrically coupled to one or more electrodes or electrical circuitry of the IMD's implantable pulse generator (IPG). In response to exposure of the IMD to an energetic electromagnetic field, a voltage signal is induced in the one or more antennas and provided, possibly via one more filters, as a control signal to the one or more switches. Receipt of the control signal by the one or more switches automatically configures the one or more switches into a non-conductive state, thereby electrically isolating the one or more lead wires from the one or more electrodes or the IPG electrical circuitry.