Implantable MRI-Safe Disk Magnet With Rotatable Dipole Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing implant systems face issues with magnetic interference during MRI examinations, leading to torque displacement, reduced magnetization, imaging artifacts, and induced voltages, particularly at high field strengths, necessitating limitations on MRI use or surgical magnet removal.
Innovation Solution
A planar coil housing with rotatable attachment magnets having a magnetic dipole parallel to the plane of the coil housing, optionally with a magnetic focus director and lubrication coating, allowing the magnets to align with the MRI field and minimize torque and demagnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional implant magnets with perpendicular magnetic dipole are used, then strong magnetic fixation is achieved, but torque displacement and demagnetization occur during MRI examinations
Solution Approach 1:
The patent changes the orientation parameter of the magnetic dipole from perpendicular to parallel relative to the skin surface. This parameter change allows the magnet to align with the MRI magnetic field lines, preventing torque displacement and demagnetization while maintaining adequate magnetic fixation force through the modified geometric relationship between the magnet and the MRI field.
Solution Approach 2:
The patent reorients the magnetic dipole from a vertical orientation (perpendicular to skin) to a horizontal orientation (parallel to skin), effectively changing the spatial dimension of magnetic field interaction. This dimensional reconfiguration allows the magnet to interact with MRI field lines in a different geometric relationship, eliminating the harmful torque effect while preserving fixation functionality.
2Reliability
If spherical implant magnets are used, then MRI compatibility is improved, but implant volume increases requiring bone recess preparation
Solution Approach 1:
The patent changes the shape parameter from spherical to planar disk-shaped magnet. This parameter change reduces the volume and profile of the implant, eliminating the need for bone recess preparation, while simultaneously changing the magnetic dipole orientation to achieve MRI compatibility through proper alignment with MRI field lines.
Solution Approach 2:
Instead of using a spherical magnet geometry to achieve MRI compatibility, the patent inverts the approach by using a planar magnet with reoriented magnetic dipole. This inversion of the conventional design paradigm achieves the same MRI compatibility goal while avoiding the volume and surgical complexity issues associated with spherical magnets.
3Volume of moving object
If conventional disk magnets with perpendicular magnetization are used, then compact implant design is achieved, but imaging artifacts and induced voltages occur during MRI
Solution Approach 1:
The patent changes the magnetization direction parameter from perpendicular to parallel relative to the skin surface. This parameter change maintains the compact disk-shaped geometry while fundamentally altering the interaction with MRI magnetic fields, thereby eliminating imaging artifacts and induced voltages caused by perpendicular magnetization during MRI examinations.
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
Enables safe MRI compatibility up to 3 Tesla without surgical intervention, reducing torque and magnetization loss, minimizing imaging artifacts, and maintaining stable magnetic fixation.
Implementation Method 1
A first attachment magnet is located within the plane of the coil housing and rotatable therein, and has a magnetic dipole parallel to the plane of the coil housing for transcutaneous magnetic interaction with a corresponding second attachment magnet
Implementation Method 2
the external magnetic field from the MRI may create a torque on the internal magnet 202, which may displace the internal magnet 202 or the whole implant housing 201 out of proper position
Implementation Method 3
optionally with a magnetic focus director and lubrication coating
Data Source
Figure 1~2
Figure 3(A)~3(B)
Figure 4(A)~4(B)
AI summary
A magnetic arrangement is described for an implantable system for a recipient patient. A planar coil housing contains a signal coil for transcutaneous communication of an implant communication signal. A first attachment magnet is located within the plane of the coil housing and rotatable therein, and has a magnetic dipole parallel to the plane of the coil housing for transcutaneous magnetic interaction with a corresponding second attachment magnet.