A flexible patch electrode with electromagnetic compatibility for fMRI
By designing flexible patch electrodes with multi-level fractal structures, the problems of traditional brain electrodes and fMRI compatibility and eddy current interference are solved, and efficient EEG signal acquisition and patient health protection are achieved.
Patent Information
- Application Number
- CN202210809455.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-07-11
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2042-07-11
AI Technical Summary
Traditional brain electrodes are difficult to compatible with fMR, and metal conductors generate eddy currents in strong magnetic fields that interfere with the quality of EEG signal and may cause local high temperature hazards.
Design a flexible patch electrode with electromagnetic compatibility with fMRI, adopting a multi-stage fractal structure of metal electrodes and isolation layers to avoid the electrode forming a closed loop circuit, reduce strong magnetic field interference, and increase the contact area between the electrode and the skin through the flexible base layer and lead structure. .
The compatibility between electrodes and fMRI is achieved, the interference of strong magnetic fields on EEG signals is reduced, the harm of eddy currents and local high temperatures is avoided, and the health and safety of patients are ensured.
Smart Images
Figure CN115153561B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of medical devices, and in particular to an fMRI electromagnetically compatible flexible patch electrode. Background Art
[0002] In the field of neuroimaging, there are two main neuroimaging tools, functional magnetic resonance imaging (fMRI) and scalp electroencephalography (EEG). Functional magnetic resonance imaging is related to the energy metabolism consumption of neuronal groups, and its spatial resolution can reach the millimeter level. However, due to the time dependence of blood oxygen levels, the temporal resolution of fMRI signals is about the second level, which is difficult to meet the requirements of temporal resolution for related neurological function research. EEG reflects synchronous neural electrical activity and has the same time scale as neurocognitive processes. However, during the transmission of EEG signals from the intracranial to the extracranial, attenuation, reflection, aliasing and other phenomena will occur, resulting in low spatial resolution of EEG signals. EEG / fMRI multimodal fusion can effectively overcome the defects of single-modal analysis and achieve high temporal resolution and high spatial resolution brain nerve activity signal acquisition. However, traditional brain electrodes are difficult to be compatible with functional magnetic resonance imaging. Functional magnetic resonance imaging has high requirements for the uniformity of magnetic field strength, and metal conductors will have a significant impact on the uniformity of the magnetic field, seriously affecting the quality of fMRI imaging. At the same time, when a conductor is placed in a changing magnetic field, an induced electromotive force will be generated inside the conductor, which will then generate eddy currents, seriously interfering with the quality of EEG signals. More importantly, the thermal effect of eddy currents can cause local high temperatures and cause harm to the human body. Summary of the invention
[0003] The present invention provides an fMRI electromagnetically compatible flexible patch electrode. The planar structural characteristics of the flexible patch electrode are utilized to prepare a conductive unit with a multi-level fractal structure, which can achieve electromagnetic compatibility with fMRI; the influence of the electrode on the fMRI imaging quality is avoided, and at the same time, the interference of a strong magnetic field on an electroencephalogram signal is greatly reduced, thereby ensuring the health of the patient.
[0004] The present invention is achieved through the following technical solutions:
[0005] An fMRI electromagnetically compatible flexible patch electrode comprises a flexible substrate layer, an electrode layer and an isolation layer.
[0006] The electrode layer is located between the flexible substrate layer and the isolation layer;
[0007] The electrode layer includes a plurality of discrete metal electrodes, and the plurality of metal electrodes are connected to form a non-enclosed structure to form a main metal electrode, and the main metal electrode is attached to the surface of the flexible base layer. The metal electrode has a multi-level fractal structure, and each level of the metal electrode is formed by connecting a plurality of discrete metal electrodes of the next level, and a plurality of metal electrodes of the same level are connected to form a non-enclosed structure;
[0008] The isolation layer is disposed in the gaps between adjacent metal electrodes, and is used to isolate the plurality of metal electrodes from each other.
[0009] As an optimization, it also includes a lead wire and a lead-out point, the metal electrode includes a contact point in contact with the skin, the contact points of the metal electrodes of the same level are connected to form a non-closed structure, the lead wire is connected to all contact points of the metal electrodes of one level, the end of the lead wire away from the contact point is the lead-out point, the lead-out point extends from the flexible base layer, the contact point is used to collect physiological signals, the lead wire is used to receive the physiological signals and transmit them to the lead-out point, and the lead-out point is used to connect to an external device to transmit the physiological signals to the outside.
[0010] As an optimization, the shape of the main metal electrode / metal electrode includes one or a combination of square and rectangle.
[0011] In this way, the main metal electrode / metal electrode is set to a square or rectangle, and as many metal electrodes as possible can be set on a flexible patch of limited area, thereby increasing the contact area between the metal electrode and the flexible patch, that is, increasing the contact area between the contact point and the human body. This can reduce the impedance between the patch electrode and the skin, avoid the generation of large eddy currents, and avoid the formation of local high temperatures that endanger human health.
[0012] As an optimization, the main metal electrode / metal electrode has a shape other than a square and a rectangle.
[0013] As an optimization, the size of the contact point of the lowest level of the metal electrode is determined according to the actual imaging accuracy.
[0014] As an optimization, the metal electrodes at each level are arranged in an m*n array, where m and n are positive integers not less than 2, wherein the metal electrodes in each row / column are connected in sequence, and only one column / row of all columns / rows are connected in sequence.
[0015] In this way, it can be ensured that contact points of the same level do not form a closed loop.
[0016] As an optimization, the metal electrodes at each level are arranged in an m*n array, where m and n are positive integers not less than 2, wherein the metal electrodes in each row / column are connected in sequence, and the metal electrodes in the same column in adjacent rows / columns are connected, and only one column / row of the metal electrodes in each row / column are connected.
[0017] In this way, it can be ensured that contact points of the same level do not form a closed loop.
[0018] As an optimization, the metal electrodes at each level are arranged in an m*n array, where m and n are positive integers not less than 2, wherein, starting from the metal electrode located in a corner, the m*n metal electrodes are connected in an S-shaped manner.
[0019] In this way, it can be ensured that contact points of the same level do not form a closed loop.
[0020] As an optimization, the isolation layer is made of a flexible material.
[0021] As an optimization, the flexible material includes polyimide, polyethylene terephthalate, polybutylene terephthalate or polyarylate.
[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0023] 1. The present invention discretizes the overall structure of the metal electrode of the electrode layer to ensure conformal adhesion of the electrode to the non-developable surface of the brain;
[0024] 2. The discretization and fractal structure of the metal electrode of the present invention realizes the compatibility of the metal electrode with fMRI, avoids the influence of the electrode on the fMRI imaging quality, greatly reduces the interference of the strong magnetic field on the EEG signal, ensures the health of the patient, and ensures a large contact area between the electrode and the skin while reducing the impedance between the electrode and the skin, avoiding the generation of large eddy currents and the formation of local high temperatures that endanger human health. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:
[0026] Figure 1 A schematic diagram of the connection structure of the first-level metal electrode of implementation 1 of an fMRI electromagnetic compatible flexible patch electrode according to the present invention;
[0027] Figure 2 for Figure 1 Schematic diagram of the connection structure of the corresponding second-level metal electrodes;
[0028] Figure 3 for Figure 2 A is an enlarged diagram in the middle;
[0029] Figure 4 A schematic diagram of the connection structure of metal electrodes according to another embodiment;
[0030] Figure 5 A schematic diagram of the connection structure of metal electrodes in another embodiment;
[0031] Figure 6 Schematic diagram of the overall structure of the fMRI electromagnetic compatible flexible patch electrode.
[0032] Marks and corresponding parts names in the attached drawings:
[0033] 1-main metal electrode, 1.1-first level metal electrode, 1.1.1-second level metal electrode, 1.1.1.1-third level metal electrode, 2-conducting wire, 3-flexible base layer. DETAILED DESCRIPTION
[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.
[0035] Example 1
[0036] An fMRI electromagnetic compatible flexible patch electrode comprises a flexible substrate layer 3, an electrode layer and an isolation layer, wherein the electrode layer is located between the flexible substrate layer 3 and the isolation layer; the electrode layer comprises a plurality of discrete metal electrodes, wherein the plurality of metal electrodes are connected to form a non-enclosed structure to form a main metal electrode 1, wherein the main metal electrode 1 is attached to the surface of the flexible substrate layer 3, and the metal electrode has a multi-level fractal structure, wherein the metal electrode of each level is formed by connecting a plurality of discrete metal electrodes of the next level, and a plurality of metal electrodes of the same level are connected to form a non-enclosed structure, thereby preventing metal electrodes of the same level from forming a closed loop to generate current and burn human skin. The non-closed structure here means that several metal electrodes do not form a closed loop. In this embodiment, it also includes leads and lead points. The metal electrodes include contact points that contact the skin. The contact points of metal electrodes of the same level are connected to form a non-closed structure. The lead wires are connected to all contact points of metal electrodes of one level. The end of the lead wire away from the contact point is the lead point. The lead point extends from the flexible base layer. The contact point is used to collect physiological signals. The lead wire is used to receive physiological signals and transmit them to the lead point. The lead point is used to connect to an external device to transmit the physiological signal to the outside. The main metal electrode 1 can be provided with one or more lead wires. When multiple lead wires are provided, each lead wire is independently provided at intervals.
[0037] The size of the contact point of the lowest level metal electrode is determined according to the actual imaging accuracy. The lowest level here can be understood as the metal electrode with the smallest size. The shape of the metal electrode and its contact point can be any shape, which can be set according to the specific situation, and the shape of each level of metal electrode and the shape of different levels of metal electrodes do not have to be the same.
[0038] The isolation layer is disposed in the gaps between adjacent metal electrodes to isolate the plurality of metal electrodes from each other.
[0039] The materials of the flexible patch and the metal electrode are conventional patches and conductive metals, and those skilled in the art can select them according to the actual application conditions. They are not the protected technical points of this patent and will not be elaborated here.
[0040] In this embodiment, the metal electrodes at the same level are all in the shape of a square. By setting the metal electrodes in a square shape, as many metal electrodes as possible can be set on a flexible patch of limited area, increasing the contact area between the metal electrodes and the flexible patch, that is, increasing the contact area between the metal electrodes and the human body, which can reduce the impedance between the patch electrode (the entire flexible patch electrode) and the skin, avoid generating a large eddy current, and avoid forming a local high temperature that endangers human health.
[0041] like Figure 1-2 As shown, Figure 1 and Figure 2 All of them represent the same main metal electrode 1 of a non-closed structure formed by connecting a number of discrete metal electrodes on the same flexible substrate layer 3. The main metal electrode 1 is composed of Figure 1 However, it should be noted that this does not mean that the main metal electrode is composed of a whole piece of metal. The bold frame only represents the general outline of the main metal electrode, and the subsequent bold frames are the same. In this embodiment, m and n are both 3, and the metal electrodes in each row are connected in sequence, and the metal electrodes in the middle column are connected in sequence. The main metal electrode 1 is composed of 9 first-level metal electrodes 1.1 connected to form a non-enclosed structure, such as Figure 3 As shown, the first-level metal electrode 1.1 is composed of 9 second-level metal electrodes 1.1.1 connected to form a non-closed structure, and the second-level metal electrode 1.1.1 is composed of 9 third-level metal electrodes 1.1.1.1 connected to form a non-closed structure. The connection relationship between the first-level, second-level and third-level metal electrodes does not need to be exactly the same, as long as the connection of the metal electrodes at each level is a non-closed structure. In this embodiment, the wire is connected to all the contact points of one of the second-level metal electrodes. If the wire only contacts some of the contact points of the second-level metal electrode, this may cause the contact points in the second-level metal electrode to form a loop. Therefore, the wire contacts all the contact points of the second-level metal to avoid the contact points in the second-level metal electrode from forming a loop.
[0042] Of course, if Figure 1 Rotating 90 degrees, the metal electrodes in each column are connected in sequence, and the metal electrodes in the middle row are connected in sequence.
[0043] The level of the metal electrode connected to the wire 2 is determined by the size of the wire 2. If the size of a metal electrode of a certain level is small and is not conducive to connection with the wire 2, the previous metal electrode of the metal electrode of this level is regarded as a whole and connected to the wire 2.
[0044] Example 2
[0045] like Figure 4 As shown, this embodiment is the same as Embodiment 1 except that the connection method of several metal electrodes connected into a non-closed structure is different from that of Embodiment 1. In this embodiment, m and n are both 3. Starting from the upper left metal electrode, adjacent metal electrodes are connected in an S-shaped manner in the horizontal direction. Of course, adjacent metal electrodes can also be connected in an S-shaped manner in the vertical direction. If Figure 4 Rotate 90 degrees to the left, and the metal electrodes on the lower left are connected in an S-shaped pattern vertically. Figure 4 Rotating 90 degrees to the right, the metal electrode on the upper right is used as the starting point, and the adjacent metal electrodes are connected in sequence in the form of an S motion starting from the vertical direction.
[0046] Example 3
[0047] like Figure 5 As shown, this embodiment is the same as the first embodiment except that the shape of the metal electrode is different.
[0048] Finally, if Figure 6 As shown, several flexible patch electrodes are attached to human skin for imaging detection.
[0049] It should also be noted that, in this specification, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.
[0050] At the same time, the devices used in this specification are all existing devices, and those skilled in the art can obtain them through purchase, reference, etc.
[0051] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
[0052] In summary, although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.
Claims
1. An fMRI electromagnetic compatible flexible patch electrode, comprising a flexible substrate layer, an electrode layer and an isolation layer, characterized in that: The electrode layer includes a plurality of discrete metal electrodes, and the plurality of metal electrodes are connected to form a non-enclosed structure to form a main metal electrode, and the main metal electrode is attached to the surface of the flexible base layer. The metal electrode has a multi-level fractal structure, and each level of the metal electrode is formed by connecting a plurality of discrete metal electrodes of the next level, and a plurality of metal electrodes of the same level are connected to form a non-enclosed structure; The isolation layer is disposed in the gap between adjacent metal electrodes, and is used to isolate the plurality of metal electrodes from each other; It also includes a lead wire and a lead-out point, the metal electrode includes a contact point in contact with the skin, the contact points of the metal electrodes of the same level are connected to form a non-closed structure, the lead wire is connected to all the contact points of the metal electrodes of one level, the end of the lead wire away from the contact point is the lead-out point, the lead-out point extends from the flexible base layer, the contact point is used to collect physiological signals, the lead wire is used to receive the physiological signals and transmit them to the lead-out point, and the lead-out point is used to connect to an external device to transmit the physiological signals to the outside.
2. The fMRI electromagnetic compatible flexible patch electrode according to claim 1, characterized in that: The shape of the main metal electrode / metal electrode includes one or a combination of square and rectangle.
3. The fMRI electromagnetic compatible flexible patch electrode according to claim 1, characterized in that: The main metal electrode / metal electrode has a shape other than a square and a rectangle.
4. The fMRI electromagnetic compatible flexible patch electrode according to claim 1, characterized in that: The size of the contact point of the lowest level metal electrode is determined according to the actual imaging accuracy.
5. The fMRI electromagnetic compatible flexible patch electrode according to claim 2 or 3, characterized in that: The metal electrodes at each level are arranged in an m*n array, where m and n are positive integers not less than 2, wherein the metal electrodes in each row / column are connected in sequence, and only one column / row of all the columns / rows are connected in sequence.
6. The fMRI electromagnetic compatible flexible patch electrode according to claim 2 or 3, characterized in that: The metal electrodes at each level are arranged in an m*n array, where m and n are positive integers not less than 2, wherein the metal electrodes in each row / column are connected in sequence, and the metal electrodes in the same column in adjacent rows / columns are connected, and only one column / row of the metal electrodes in each row / column are connected.
7. The fMRI electromagnetic compatible flexible patch electrode according to claim 2 or 3, characterized in that: The metal electrodes at each level are arranged in an m*n array, where m and n are positive integers not less than 2, wherein, starting from the metal electrode located in a corner, the m*n metal electrodes are connected in an S-shaped connection manner.
8. The fMRI electromagnetic compatible flexible patch electrode according to claim 1, characterized in that: The isolation layer is made of flexible material.
9. The fMRI electromagnetic compatible flexible patch electrode according to claim 8, characterized in that: The flexible material includes polyimide, polyethylene terephthalate, polybutylene terephthalate or polyarylate.