Rotatable Cochlear Implant Magnet for MRI Torque Stability
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Solution Overview
Problem
Conventional MRI compatible magnets in cochlear implants are prone to displacement and demagnetization during MRI examinations, causing potential tissue damage, imaging artifacts, and auditory hallucinations due to interaction with external magnetic fields.
Innovation Solution
An MRI compatible magnet design featuring an axisymmetric polygonal disk-shaped magnet with rotating N and S poles, housed within a bracket and shells, allowing flexible rotation to minimize the included angle with external magnetic fields, thereby reducing torque and demagnetization risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the magnet is fixed in a conventional coin shape with perpendicular magnetic dipole, then the structure is simple and easy to manufacture, but the magnet is prone to displacement and demagnetization during MRI examinations
Solution Approach 1:
The patent applies the dynamics principle by making the magnet rotatable within the bracket rather than fixed. The magnet can rotate to change its orientation relative to the external magnetic field during MRI examinations, allowing it to adapt to different field directions and reduce torque effects. This dynamic adjustment capability resolves the contradiction by maintaining reliability through adaptability while keeping the overall structure relatively simple.
Solution Approach 2:
The patent applies parameter changes by altering the magnetic dipole orientation from a fixed perpendicular arrangement to a rotatable configuration. This allows the magnetic pole direction to change in response to external magnetic field conditions during MRI, transforming the magnet from a static component to one with variable parameters that can optimize performance under different operating conditions.
2Reliability
If the magnet is fixed with perpendicular magnetic dipole to skin, then the positioning is simple, but the external magnetic field produces torque that displaces the magnet or implant shell
Solution Approach 1:
The rotatable magnet design allows the magnetic dipole to dynamically adjust its orientation in response to external magnetic field torque. Instead of being fixed and vulnerable to displacement, the magnet can rotate to align more favorably with the external field, reducing the torque effect and preventing displacement of the magnet or implant shell during MRI examinations.
Solution Approach 2:
The patent converts the harmful torque effect into a beneficial alignment mechanism. The external magnetic field torque that would normally cause displacement is instead used to rotate the magnet into a favorable orientation, where the magnetic dipole aligns with the external field direction, minimizing further torque and stabilizing the implant position.
3Reliability
If the magnet is fixed in conventional configuration, then the manufacturing is straightforward, but the magnetization is reduced or eliminated by external magnetic field during MRI
Solution Approach 1:
The rotatable magnet mechanism allows the magnetic component to dynamically adjust its orientation during MRI examinations, preventing the external magnetic field from completely demagnetizing it. By able to rotate and align with the field, the magnet maintains residual magnetization and functionality, whereas a fixed magnet would have its magnetization reduced or eliminated.
4Reliability
If the magnet is fixed with perpendicular orientation, then the structure is simple, but imaging artifacts and auditory hallucinations occur during MRI
Solution Approach 1:
The rotatable magnet design improves MRI compatibility by allowing the magnet to dynamically adjust its orientation during the examination. This reduces the interaction between the fixed perpendicular magnetic dipole and the external MRI magnetic field, thereby minimizing imaging artifacts and auditory hallucinations while maintaining a relatively simple overall structure.
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 design enhances the reliability of cochlear implants by preventing displacement and demagnetization during MRI, eliminating the need for surgical removal and reimplantation, and minimizing damage and pain for patients.
Implementation Method 1
the external magnetic field from MRI can produce a torque on the MRI compatible magnet of the internal cochlear implant
Implementation Method 2
the MRI compatible magnet of the cochlear implant interacts with the external magnetic field applied to MRI
Implementation Method 3
the needle rollers are accommodated in the positioning slots, and the needle rollers are cylindrical and can axially roll in the positioning slots without slipping off
Data Source
AI summary
The present invention discloses an MRI compatible magnet for a cochlear implant, comprising a base, an upper shell, a bracket, a magnet, needle rollers and a lower shell, wherein the upper shell and the lower shell form a closed space, and the magnet and the bracket are arranged in the closed space; the magnet is in an axisymmetric polygonal disk shape; the magnetic pole of the magnet is divided into two halves from the top view, one half is an N pole, and the other half is an S pole; the magnet is arranged in the bracket; the bracket is matched with the magnet in shape, and the bracket rotates with the magnet when the magnet rotates axially; a plurality of positioning slots are provided on the outer side face of the bracket; and , the needle rollers are accommodated in the positioning slots, and the needle rollers are cylindrical and can axially roll in the positioning slots without slipping off. The MRI compatible magnet for a cochlear implant provided by the present invention can flexibly rotate on the bracket according to the change of the direction of an external magnetic field, so that the N pole and the S pole of the magnet can be freely switched in the spatial direction, and it is unnecessary to take out the cochlear implant and the internal magnet during examinations in a strong magnetic field such as MRI.