Rotatable Implant Magnet Case for MRI Torque Reduction
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Solution Overview
Problem
Existing implant systems with magnet arrangements face challenges during Magnetic Resonance Imaging (MRI) due to interactions between the implant magnet and the strong external magnetic field, which can cause torque, displacement, and demagnetization, potentially damaging adjacent tissue and creating imaging artifacts.
Innovation Solution
The implementation of an implantable hearing implant with a magnet case that is rotatable about a case rotation axis perpendicular to its outermost surface, and an implant magnet arrangement comprising cylindrical magnets with a V-shaped magnetic angle, allowing the magnets to align and rotate in response to external magnetic fields to minimize torque and maintain magnetic attraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional implant magnet with perpendicular magnetic dipole moment is used, then strong magnetic attraction is achieved for holding the external device, but torque and displacement occur during MRI due to interaction with external magnetic field
Solution Approach 1:
The implant magnet is made rotatable about an axis perpendicular to the skin surface, allowing it to dynamically realign its magnetic dipole moment with the external MRI magnetic field, thereby minimizing torque while maintaining holding force through the magnetically coupled external device
Solution Approach 2:
The magnetic dipole moment direction is changed from fixed perpendicular orientation to可变 orientation that can align with external magnetic fields, fundamentally changing the magnet's response characteristics to external fields during MRI
2Reliability
If the implant magnet is made rotatable to minimize torque during MRI, then magnetic attraction stability is improved, but device complexity increases
Solution Approach 1:
A rotatable magnet case with bearing support enables the implant magnet to dynamically adjust its orientation in response to external magnetic fields, providing passive adaptive protection against torque and displacement during MRI procedures
Solution Approach 2:
The rotation mechanism operates passively through magnetic field interaction itself, with the external MRI field providing the torque that naturally realigns the implant magnet without requiring active sensors, motors, or control systems
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
This solution effectively reduces the impact of strong external magnetic fields during MRI, minimizing torque and maintaining strong magnetic attraction between the implant and external devices, thereby ensuring the implant's stability and safety during MRI procedures.
Implementation Method 1
an implant magnet arrangement including one or more cylindrical magnets, each cylindrical magnet having a center cylinder axis perpendicular to the case rotation axis, configured to be rotatable about the center cylinder axis
Implementation Method 2
The magnet case is configured to be rotatable about a case rotation axis which is at least approximately perpendicular to the outermost surface of the implant device
Data Source
AI summary
An implant device is disclosed that includes signal processing circuitry configured to receive an implant communications signal transmitted from an external transmitting coil, a magnet case configured to be rotatable about a case rotation axis, and an implant magnet arrangement within the magnet case configured to cooperate with an external holding magnet in an external device to magnetically hold the external device against overlying skin. The implant magnet arrangement includes a plurality of cylindrical magnets, each with a center cylinder axis perpendicular to the case rotation axis, and each configured to be rotatable about a center cylinder axis. The north and south magnetic poles are arranged with respect to each other so as not to lie on a common diameter through the center cylinder axis such that the north and south magnetic directions form a magnetic angle less than 180 degrees with a vertex at the center cylinder axis.