Mri Compatible Implant Comprising Electrically Conductively Closed Loops
First Claim
1. An implant comprising:
- electrically-conductive closed loops forming an apertured wall of the implant with an interior volume, each of said loops being formed from loop portions providing electrically-conductive current pathways within which eddy currents are liable to be induced when subjected to a time-dependent external magnetic field, each of said loops including a first current pathway and a second current pathway wherein said first current pathway and said second current pathway are arranged such that, regardless of the direction of said external magnetic field, the direction of the eddy current that would be induced by said field in said second current pathway is the reverse of the direction of the eddy current that would simultaneously be induced by said field in said first current pathway, thereby to prevent flow of eddy currents in each of said loops.
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Accused Products
Abstract
The present invention relates to an implant 100 which comprises a plurality of electrically-conductive closed loops (300A, 300B, 300C, 300D; 120A, 120B, 120C, 120D each constituted from a plurality of loop portions such as struts (400, 500). The loops together form apertured walls of a cage with an interior volume, and the portions in any one said loop providing electrically-conductive pathways within which eddy currents are liable to be induced when the implant is subjected to an time-dependent external magnetic field, with each said loop comprising at least first and second said pathways. The implant is characterized in that the first and second pathways are arranged such that, in any particular magnetic field, the direction of the eddy current that would be induced in the second pathway is the reverse of the direction of the eddy current that would be induced in the first pathway, so as to mitigate the tendency of the implant to function in said magnetic field as a Faraday cage.
66 Citations
36 Claims
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1. An implant comprising:
electrically-conductive closed loops forming an apertured wall of the implant with an interior volume, each of said loops being formed from loop portions providing electrically-conductive current pathways within which eddy currents are liable to be induced when subjected to a time-dependent external magnetic field, each of said loops including a first current pathway and a second current pathway wherein said first current pathway and said second current pathway are arranged such that, regardless of the direction of said external magnetic field, the direction of the eddy current that would be induced by said field in said second current pathway is the reverse of the direction of the eddy current that would simultaneously be induced by said field in said first current pathway, thereby to prevent flow of eddy currents in each of said loops. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. An implant tube comprising:
an electrical conductor, said electrical conductor having a plurality of closed loops electrically insulated from each other, each of said closed loops having a periphery of a string of equal area lobes that are within said closed loop, and every one of said lobes having a counterpart lobe located diametrically opposite on the implant tube. - View Dependent Claims (36)
Specification