CN104083823A - Implanted electrode compatible with MRI - Google Patents
Implanted electrode compatible with MRI Download PDFInfo
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- CN104083823A CN104083823A CN201410307770.0A CN201410307770A CN104083823A CN 104083823 A CN104083823 A CN 104083823A CN 201410307770 A CN201410307770 A CN 201410307770A CN 104083823 A CN104083823 A CN 104083823A
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Abstract
The invention provides an implanted electrode compatible with MRI. The implanted electrode comprises an electrode conduit, the far end of the electrode conduit is provided with at least one contact, and the near end of the electrode conduit is provided with at least one connector. The connector is connected with one or more contacts through a wire arranged in the electrode conduit. A net-shaped shielding layer with the biocompatibility is arranged outside the electrode conduit to form shielding protection on the wire in the electrode conduit, the induced current generated by the wire under the activation of a radio frequency magnetic field in the MRI is weakened, and therefore the electrode contacts can be prevented from being heated. The two ends of the net-shaped shielding layer are provided with packing rings directly connected with the net-shaped shielding layer. A detecting loop can be formed by the net-shaped shielding layer, the packing rings at the two ends of the net-shaped shielding layer, the connector, the biological tissue and a controller, and a measuring circuit is arranged in the controller and is capable of measuring the impedance at the two ends of the detecting loop and being used for assessing the integrity of the shielding layer.
Description
Technical field
The invention belongs to technical field of medical instruments, particularly a kind of implanted electrode that can weaken MRI and scan the impact on its generation under MRI scanning circumstance.
Background technology
Mr imaging technique (Magnetic Resonance Imaging, MRI) compared with other imaging techniques (as X ray, CT etc.), there is more significant advantage: nuclear magnetic resonance is more clear, soft tissue is had to very high resolving power, and to human body without ionization radiation injury.So mr imaging technique is widely used among the clinical diagnosis of modern medicine.According to estimates, nowadays the whole world has at least 6,000 ten thousand cases to utilize nmr imaging technique inspection every year.
When MRI work, having three magnetic fields plays a role.A high-intensity even magnetostatic field B0, one can be adjusted to the gradient magnetic of any direction, and for radio frequency (RF) magnetic field of excited nucleus magnetic resonance.That wherein the intensity of magnetostatic field B0 is common is 1.5T and 3.0T, and magnetostatic field B0 and gradient magnetic collaborative work are to provide the spatial positional information of magnetic resonance signal; And radio-frequency (RF) magnetic field is high-power, a high-frequency time-varying magnetic field, its frequency is Larmor frequency, i.e. f=γ B0, wherein γ=42.5MHz/T.So, be in the MRI of 1.5T or 3.0T at common magnetostatic field B0, the frequency of radio-frequency (RF) magnetic field is about respectively 64MHz and 128MHz.
Although MRI can not have direct injury to human body, if but implantable medical devices (Implantable Medical Device is installed in patient body, IMD), such as cardiac pacemaker, defibrillator, vagus nerve stimulator, spinal cord stimulation device, brain deep brain stimulation device etc., when MRI work, three magnetic fields of required use bring safely very large hidden danger just can to patient's life and health.Wherein a most important hidden danger is the induction heating of implantable medical devices in radio-frequency (RF) magnetic field, particularly for those with elongated conductive structures, and the medical apparatus and instruments (typically for example brain deep brain stimulation device is with extension lead and electrode cable, and cardiac pacemaker is with electrode wires) that this elongated conductive structures can partly contact with tissue.The patient of these implantable medical devices is housed in body in carrying out MRI scanning, may occurs serious temperature rise in elongated conductive structures with the position that tissue contacts, such temperature rise meeting causes serious injury patient.But most of patient who implants IMD needs to carry out MRI inspection in apparatus life cycle, and radio-frequency (RF) magnetic field is responded to the potential safety hazard of bringing and is caused this part patient to be rejected checking.So, the MRI compatibility function meaning of exploitation implantable medical devices is remarkable, and because the induction heating effect of radio-frequency (RF) magnetic field is mainly reflected in elongated conductive structures as on electrode, so exploitation can not have very high market value and using value because the induction heating effect of radio-frequency (RF) magnetic field causes the electrode of serious temperature rise under MRI environment.
The reason that under radio-frequency (RF) magnetic field, the induction of elongated conductive structures is heated is the coupling between elongated conductive structures and radio-frequency (RF) magnetic field.Being coupling between elongated conductive structures and radio-frequency (RF) magnetic field produces faradic current in elongated conductive structures, the part that faradic current contacts with tissue by conductive structure is carried in tissue, and the faradic current that for example electrode wires produces under radio-frequency (RF) magnetic field flows to tissue by electrode contacts.Like this, near tissue electrode contacts, electric current density is higher, causes ohm of tissue to be heated.
A thinking that solves foregoing problems is to attempt to reduce the radio frequency induction electric current in electrode wires, thereby reduces near the electric current density of organizing electrode contacts, reduces ohm heat of tissue.Electrode wires is designed to have high impedance and can weakens radio frequency induction electric current, but the while also can be limited the function of electrode wires itself; Arrange that in the interface of electrode contacts/wire LC resonance filter can reflected radio faradic current, stop it to flow into tissue, but this can strengthen again the current intensity of resonance filter and wire itself, cause the temperature rise of resonance filter and wire itself, when serious, even can melt electrode catheter.Adopting shielding is a feasible scheme: the screen layer coated electrode wire conduit outer surface that utilizes good conductor to form, under radio-frequency (RF) magnetic field environment, the inner side at screen layer is formed the magnetic field offseting with MRI radio-frequency (RF) magnetic field by the eddy current that screen layer is excited to produce, thereby weaken the impact of radio-frequency (RF) magnetic field on electrode wires, thereby reduce the radio frequency induction electric current in electrode wires.
Summary of the invention
The invention provides a kind of improved implanted electrode, described implanted electrode can weaken or eliminate the impact of radio-frequency (RF) magnetic field on itself in MRI scanning circumstance, weakens or eliminates near the temperature rise of organizing electrode contacts.
The present invention is achieved through the following technical solutions:
A kind of implanted electrode, comprises an elongated electrode catheter, is furnished with at least one contact at the far-end of described electrode catheter, at the near-end of described electrode catheter, at least one adapter is set; Described contact is connected by respectively with one adapter of wire that is arranged in electrode body inside; Outside described electrode catheter, be furnished with the mesh shields layer that at least one deck is not directly connected with adapter with described contact, described mesh shields layer uses the electric good conductor material with biocompatibility to make; The integrity of described mesh shields layer can be detected by controller.
Preferably, described controller comprises impedance magnitude measuring circuit.
Preferably, described controller detects the impedance loop size Z that comprises mesh shields layer by impedance magnitude measuring circuit
mx, and with set threshold value Z
mthcompare, work as Z
mxbe greater than Z
mthtime think that mesh shields layer breaks down.
Preferably, described threshold value Z
mthset in advance according to priori experience, or controller provides setting Z
mthfunction, when carrying out impedance magnitude measurement after implant into body and setting according to the impedance loop size of actual measurement.
Preferably, carry out respectively the measurement of impedance magnitude at far-end and the near-end of mesh shields layer.
Preferably, the near-end setting of described mesh shields layer can be brought ring together with the near-end that described controller is connected, or the far-end of described mesh shields layer arranges far-end and bring ring together, is connected, and then can be connected with controller by described wire with an adapter of near-end.
Preferably, the near-end of described mesh shields layer and far-end arrange respectively near-end bring together ring and far-end bring ring together, described near-end is brought ring together and can be connected with controller, and described far-end is brought ring together and is connected with an adapter of near-end by wire, and then can be connected with controller;
Described near-end bring together ring and described far-end bring together ring be directly connected with described mesh shields layer, the integrity of described mesh shields layer can by near-end bring together ring and/or far-end bring together encircle detection.
Preferably, the A end and B end, the resistance R of the impedance in described loop and impedance magnitude measuring circuit of described impedance magnitude measuring circuit accessed respectively at the two ends in described loop
1series connection produces dividing potential drop, impedance loop size Z
mxvariation make the voltage V of operational amplifier normal phase input end
1also change; V
1through the voltage follower being formed by operational amplifier, pass through V
obe input to the ADC input of controller; V
1changing Pattern be:
Wherein, reference voltage V
refshould be consistent with the ADC reference voltage of controller.
Preferably, the A end and B end, the voltage reference diode D of described impedance magnitude measuring circuit of described impedance magnitude measuring circuit accessed respectively at the two ends in described loop
zwith operational amplifier A
0form a constant-current source, U
zfor voltage reference diode D
zreference voltage, the output current of constant-current source size is i
t=U
z/ R
z; Described loop is accessed in constant-current source as load impedance, i
tflow into described loop through B end, the described loop flow back to described impedance magnitude measuring circuit by A end of flowing through; Measure and detect between two ends, loop, be i.e. potential difference Δ V=V between B end and A end
2-V
1, can be by formula Z
mx=Δ V/i
scalculate the impedance magnitude Z detecting between two ends, loop
mx.
The present invention also provides a kind of medical assembly, it is characterized in that, comprises according to the implanted electrode described in any one in above technical scheme.
Beneficial effect of the present invention is:
The present invention arranges that at implanted electrode conduit outer wall one deck adopts the electric good conductor material with biocompatibility to weave the mesh shields layer forming, and in the high-frequency RF magnetic field in MRI scanning, can produce eddy current in mesh shields layer; The eddy current producing can be in opposing magnetic field offseting with the RF magnetic field of MRI scanning of screen layer internal excitation, thereby the impact that the RF magnetic field that can reduce MRI scanning produces electrode cable, reduce the electric current density at electrode cable and electrode contacts place, thereby suppress even to eliminate near heating electrode contacts, thereby ensure the safety of implanted electrode in MRI scanning.Described mesh shields layer can be brought ring together with described near-end, far-end is brought ring together, brought together and encircle the adapter being connected, the detection in series loop such as shell and biological tissue of described controller with described far-end; Described controller inside arranges impedance magnitude measuring circuit; The described described impedance magnitude measuring circuit of two ends, detection loop access.Described impedance magnitude measuring circuit can be measured the impedance magnitude detecting between two ends, loop, and then judges the integrity of screen layer, reduces and even eliminates because screen layer damages the security risk in MRI scanning causing.
Brief description of the drawings
Fig. 1 is structural representation of the present invention
Fig. 2 is the structural representation of mesh shields layer segment according to an embodiment of the present
Fig. 3 is the principle schematic that the present invention suppresses radio frequency induction heating
Fig. 4 is the thermograph data that adopt in the MRI scanning that the electrode sample of the inventive method manufacture is 3.0T in main field
Fig. 5 is the schematic diagram that detects a kind of scheme of mesh shields layer integrity in the present invention
Fig. 6 is the schematic diagram that detects the another kind of scheme of mesh shields layer integrity in the present invention
Fig. 7 is the schematic diagram that detects the another kind of scheme of mesh shields layer integrity in the present invention
Fig. 8 is the principle schematic of impedance magnitude measuring circuit used in the present invention
Detailed description of the invention
The implanted electrode that the invention provides a kind of MRI compatibility, is further detailed the present invention below in conjunction with the drawings and specific embodiments.
Fig. 1 has shown a kind of according to a case study on implementation of the present invention.Some nerve stimulators, such as brain deep brain stimulation electrode has the structure of Fig. 1.An implanted electrode for MRI compatibility, is characterized in that comprising the electrode catheter 1 of an elongated flexible.Be furnished with at least one contact 2 at the far-end of described electrode catheter 1, at the near-end of described electrode catheter 1, at least one adapter 3 be set; Described adapter 3 is connected with one or more contacts 2 respectively by the wire 4 that is arranged in electrode catheter 1 inside; Outside described electrode catheter 1, arrange the mesh shields layer 5 that one deck is not connected with adapter 3 with described contact 2; On described mesh shields layer 5, be provided with near-end bring together ring 6 with far-end bring together ring 7; Near-end is brought ring 6 together, far-end is brought ring 7 together and is directly connected with mesh shields layer 5, and near-end is brought ring 6 together and can be connected with controller 8; In described adapter 3 one bring ring 7 together with far-end and be connected by being arranged in the wire 4 of electrode catheter inside.
Described contact 2 use have the electric good conductor material of biocompatibility to be made, and includes but are not limited to the metal material with biocompatibility, or has conducting high polymers thing of biocompatibility etc.
Described adapter 3 use have the electric good conductor material of biocompatibility to be made, and includes but are not limited to the metal material with biocompatibility, or has conducting high polymers thing of biocompatibility etc.
One or more realizations in the methods such as being connected between described electrode contacts 2, adapter 3 and electrode cable 4 can be by crimping, tie up, screw is fixed, bonding, welding.
Electrode contacts 2 is implanted to brain depths ad-hoc location, and electrode contacts 2 is connected with controller 8 by wire 4 and adapter 3, and controller 8 just can send high frequency electric pulse constantly, by particular core group in electrode contacts 2 Stimulation of The Brains, thereby reaches therapeutic effect.Wherein wire 4 is typical elongated conductive structures, carrying out MRI when scanning, easily under the impact of radio-frequency (RF) magnetic field, produces faradic current, the faradic current wire 4 of flowing through, and spread in biological tissue by electrode contacts 2.Because the electric current density near biological tissue contact 2 is larger, easily produce serious tissue heating.Mesh shields layer 5 in the present invention is in order to address this problem, and this mesh shields layer 5 has the function in shielded radio frequency magnetic field, and has good biocompatibility, can alleviate and even eliminate the potential safety hazard of this implanted electrode in the time carrying out MRI scanning.
Described mesh shields layer 5 uses the electric good conductor material with biocompatibility to make, include but are not limited to the metal material with biocompatibility, as platinum, platinum alloy, iridium, iridium alloy titanium, titanium alloy, rustless steel, Nitinol, cobalt-base alloys etc., or there is the conducting high polymers thing of biocompatibility or carbon nanotube conductor or carbon nanotube-based material.
Described mesh shields layer 5 is single or multiple lift web frame.Fig. 2 has shown a kind of feasible web frame, but apparently, and feasible web frame is incessantly a kind of, allly can make those skilled in the art can rationally guess the web frame inventing by logical reasoning, all should list protection domain in.
Described mesh shields layer 5 can form with the fibrage that the electric good conductor material with biocompatibility is made.Weaving method can be monofilament braiding or doubling braiding.In order to ensure good shield effectiveness, described mesh shields layer should be without hole or gap.
The diameter of the described electric good conductor fiber with biocompatibility should be within the scope of this: for ensureing that described mesh shields layer has enough thickness, make described mesh shields layer have good shield effectiveness to RF magnetic field, the diameter of fiber should be not less than 0.02mm; For the implanted electrode entirety that ensures described MRI compatibility has good pliability and anti-fatigue performance, the diameter of fiber should be not more than 0.2mm.
On described mesh shields layer 5, arrange near-end bring together ring 6 and far-end bring together ring 7.
Described near-end is brought ring 6, far-end together and is brought the electric good conductor material that ring 7 use have a biocompatibility together and make, and includes but are not limited to the metal material with biocompatibility, or has the conducting high polymers thing etc. of biocompatibility.Near-end bring together ring 6, far-end bring together between ring 7 and mesh shields layer 5 be connected can be by one or more realizations in the methods such as crimping, bonding, welding.
In order to ensure safety, the integrity of described mesh shields layer 5 need to be detected; Described mesh shields layer 5 can be brought ring 6 together with described near-end, far-end is brought ring 7 together, brought with described far-end the detection in series loop such as shell 9 and biological tissue of encircling 7 adapters that are connected 3, described controller 8 together; Detecting loop can be connected with controller 8.Controller 8 inside arrange impedance magnitude measuring circuit 10.
Described impedance magnitude measuring circuit 10 can be measured the impedance detecting between two ends, loop, according to testing result and then can assess the integrity of mesh shields layer 5.
Described conduit 1 is made up of one or more materials in polyurethane material, silastic material and nylon material.
Described wire 4 is made up of the electric good conductor material with biocompatibility, includes but are not limited to the metal material with biocompatibility, or has the conducting high polymers thing of biocompatibility, or carbon nanotube conductor or carbon nanotube-based material; For transmit the signal of telecommunication between electrode contacts 2 and adapter 3.
Fig. 3 a and Fig. 3 b show that the present invention suppresses the principle of the radio frequency induction heating of implanted electrode in the time that MRI scans.The radio-frequency (RF) magnetic field of MRI scanning is a high frequency time-varying magnetic field, according to Faraday law of electromagnetic induction, at radio-frequency (RF) magnetic field H
ceffect under, in the elongated wire 4 in the electrode catheter 1 of the implanted electrode of making according to conventional art, can produce along its length faradic current i '.Make because electrode cable 4 is electricity consumption good conductors, and have very long length, so faradic current i ' is very large.And electrode cable 4 can only be electrically connected by electrode contacts 2 and biological tissue of human body formation, so the radio frequency induction current i producing in electrode cable 4 ', all flow to tissue through electrode contacts 2.Thereby, near tissue electrode contacts 2, there is very large electric current density, produce serious temperature rise.
Implanted electrode constructed in accordance is arranged one deck mesh shields layer 5 at the outer wall of electrode catheter 1.As shown in Figure 3 a, at radio-frequency (RF) magnetic field H
ceffect under, according to Faraday law of electromagnetic induction, in mesh shields layer 5, can produce faradic current i
s; And faradic current i
sin the space that can surround at mesh shields layer 5 again, produce a magnetic field H
s; According to Lenz's law, by faradic current i
sthe magnetic field H exciting
sdirection always with radio-frequency (RF) magnetic field H
copposite direction, with partial offset radio-frequency (RF) magnetic field H
cmode, magnetic field H
sweaken radio-frequency (RF) magnetic field H
cthe impact that electrode cable 4 is produced, and then reduced radio frequency induction current i ', reduce the electric current density in tissue, reach the effect that suppresses temperature rise.
5 pairs of radio frequency magnetic field H of mesh shields layer
cshield effectiveness be directly dependent in mesh shields layer 5 the faradic current i producing
ssize.So mesh shields layer 5 should make electricity consumption good conductor material make.Particularly, mesh shields layer 5 can make the braiding of electricity consumption good conductor material fiber form in the present invention.In addition, the faradic current i in mesh shields layer 5
scan cause equally the temperature rise of mesh shields layer 5 own.But as shown in Figure 3 b,, because mesh shields layer 5 is very large with the contact area of tissue, the heat Q producing in mesh shields layer 5 can distribute equably in tissue, and can not produce in certain violent temperature rise.
Fig. 4 has shown the result of implanted electrode constructed in accordance experiment measuring in model.Scan approximately 10 minutes with the MRI that main field strength is 3.0T.Use can immune electromagnetic interference optic fiber thermometer record the temperature data of 2 places, sample electrode contact and mesh shields layer 5 outer.Two samples all adopt version demonstrated in Figure 1.According to experimental data, implanted electrode constructed in accordance, than the implanted electrode of manufacturing according to conventional art, has significantly reduced the radio frequency induction temperature rise at electrode contacts 2 places, and reduction amplitude exceedes 90%.Meanwhile, in mesh shields layer 5 outer, also do not observe obvious temperature rise.
The integrity of described mesh shields layer 5 has important impact to its shield effectiveness.In model, the result of experiment measuring shows, if mesh shields layer 5 ruptures, can seriously undermine its shield effectiveness to MRI radio-frequency (RF) magnetic field, and the radio frequency induction temperature rise of electrode contacts 2 outers in MRI scanning process is significantly improved.And implanted electrode in patients with implantation body after, near the musculation in patient's daily life implant site can stretch, compresses, bending, reverse implanted electrode.So the mesh shields layer 5 on implanted electrode tends in the ambient stress in very severe.Especially in the time that electrode is implanted near the position of those motion amplitudes very large (as cervical region, joint etc.) or motion frequency very high (as heart), this situation is particularly serious.So in the long-term process of implanting, likely can there is fatigue fracture in described mesh shields layer 5.Although what impact the fracture of mesh shields layer 5 can not have to the therapeutic effect of whole system, if the implanted electrode rupturing with mesh shields layer 5 carries out MRI scanning, bring very large risk can to patient's life and health.So be necessary to provide corresponding function, doctor can, before patient carries out MRI scanning, be assessed the integrity of mesh shields layer 5.
Fig. 5 has shown structure according to an embodiment of the present.Use structure as shown in Figure 5, can directly measure the impedance between mesh shields layer 5 two ends, thereby judges the integrity of mesh shields layer 5.Because the electric conductivity of biological tissue is poor, for example, in tissue, the resistivity of muscular tissue is about 90 Ω cm, and the resistivity of fatty tissue is about 10.8*10
2Ω cm; And the conductor material that mesh shields layer uses has good electric conductivity, resistivity as stainless in 316L is about 74*10
-6Ω cm, the resistivity of platinumiridio is about 10*10
-6Ω cm, the resistivity of titanium alloy is about 160*10
-6Ω cm, the resistivity of Nitinol is about 82*10
-6Ω cm; The resistivity of these materials is all than muscular tissue or low 6 the above orders of magnitude of fatty tissue.So, mesh shields layer 5 keep complete in, between its near-end and far-end directly by 5 conducting of mesh shields layer, impedance very little (a few to tens of ohm); And there is fracture once somewhere on mesh shields layer 5, between its near-end and far-end, need to pass through biological tissue's conducting at breaking part, thereby impedance meeting significantly improves.As shown in Figure 5, in controller 8 internal placement impedance magnitude measuring circuits 10; The far-end of mesh shields layer 5 is brought ring 7 together by far-end and is brought one end of the impedance magnitude measuring circuit 10 in ring 7 adapter being connected 3 access controllers 8 by wire 4 and far-end together, and the near-end of mesh shields layer 5 is brought the other end of the impedance magnitude measuring circuit 10 in ring 6 access controllers 8 together by near-end.Impedance magnitude measuring circuit 10, adapter 3, far-end are brought ring 7 together, mesh shields layer 5, near-end are brought together between ring 6 and formed loop, just can realize the impedance magnitude between mesh shields layer 5 two ends is directly measured, thereby judge the integrity of mesh shields layer 5.The method that judges the integrity of mesh shields layer 5 is a threshold value comparison method, and controller 8 detects the impedance loop size Z that comprises mesh shields layer 5 by impedance magnitude measuring circuit 10
mx, and with a certain threshold value Z
mthcompare, work as Z
mxbe greater than Z
mthtime think that mesh shields layer 5 breaks down, this Time Controller 8 by sound propose warning, maybe will be transferred to outside program control device by the modes such as sound or image or word demonstration propose warning.Threshold value Z
mthrelevant with product property and the application scenario of practical application, can set in advance according to priori experience, or controller provides setting Z
mthfunction, when carrying out impedance magnitude measurement after product implant into body and setting concrete Z according to the impedance loop size of actual measurement
mthcan be according to the impedance loop size Z repeatedly measuring
mxmeansigma methods or maximum, be multiplied by a certain safety coefficient determine.The scheme that Fig. 5 shows it is advantageous that testing result is direct, and reliability is high.
Fig. 6 a-6c has shown according to another kind of example structure of the present invention.In structure as shown in Figure 6 a, the far-end of mesh shields layer 5 is brought together ring 7 and is brought together with far-end one end of encircling the impedance magnitude measuring circuit 10 in 7 adapter being connected 3 access controllers 8 by far-end, and the near-end of mesh shields layer 5 is not connected with impedance magnitude measuring circuit 10.The other end of impedance magnitude measuring circuit 10 is connected with the shell 9 of controller 8, between the shell 9 of controller 8 and biological tissue of human body, is conducting.Impedance magnitude measuring circuit 10, adapter 3, far-end are brought together between ring 7, mesh shields layer 5, biological tissue, controller housing 9 and are formed loop.Impedance magnitude measuring circuit 10 can be to this impedance loop size Z
mxmeasure.Impedance loop size Z
mxthe mesh shields layer 5 that detects loop to direct access is relevant with the contact area of biological tissue, and in the time that fracture occurs mesh shields layer 5, its direct access detects the part in loop and the contact area of biological tissue reduces, and will cause measuring the big or small Z of impedance
mxrise, can judge accordingly the integrity of mesh shields layer 5.Fig. 6 b and Fig. 6 c have shown and the situation while there is fracture intact at mesh shields layer 5 of detection scheme as shown in Figure 6 a as an example of brain deep brain stimulation device example.In the time that mesh shields layer 5 keeps complete, as shown in Figure 6 b, what directly access detected loop is whole mesh shields layer 5.And in the time that fracture occurs mesh shields layer 5 somewhere, as shown in Fig. 6 c, in mesh shields layer 5, directly access detects only bringing together and encircle 7 to the part between fracture position from far-end of loop.In the time that fracture occurs mesh shields layer 5, the area that the direct access of mesh shields layer 5 detects loop is less than the area of whole mesh shields layer 5.So, in the time there is fracture in mesh shields layer 5, the impedance loop size Z that impedance magnitude measuring circuit 10 is measured
mxin the time that keeping complete, mesh shields layer 5 will be improved.Can adopt threshold value comparison method to judge whether mesh shields layer 5 destroys, controller 8 detects the big or small Z of impedance loop by impedance magnitude measuring circuit 10
mx, because the conductivity of biological tissue is far below mesh shields layer 5, therefore the size of this impedance mainly detects by direct access the area that the mesh shields layer 5 in loop contacts with biological tissue and determines, and area is larger, impedance magnitude Z
mxlower, by by Z
mxwith a certain threshold value Z
mthcompare the integrity that judges mesh shields layer 5.Work as Z
mxbe greater than Z
mthtime think that mesh shields layer 5 breaks down, this Time Controller 8 by sound propose warning, maybe will be transferred to outside program control device by the modes such as sound or image or word demonstration propose warning.Threshold value Z
mthrelevant with product property and the application scenario of practical application, comprise the material of biological tissue's type of contacting with mesh shields layer 5, mesh shields layer 5 and architectural characteristic and and biological tissue between interface impedance characteristic etc., Z
mthcan set in advance according to priori experience, or controller provides setting Z
mthfunction, when carrying out impedance magnitude measurement after product implant into body and setting concrete Z according to the impedance loop size of actual measurement
mthcan be according to the impedance loop Z repeatedly measuring
mxmeansigma methods or maximum, be multiplied by a certain safety coefficient determine.
Due to the immunoreation of biological tissue, electrode is implanted rear surface and is occurred possibly connective tissue proliferation, causes measuring the raising of impedance magnitude, and the state of biological tissue is constantly to change simultaneously, can cause the fluctuation of impedance magnitude measurement result.Integrity judgement for fear of these interference factors to mesh shields layer 5, can carry out respectively the measurement of impedance magnitude at the far-end of mesh shields layer 5 and near-end, far-end and near-end by mesh shields layer 5 all access measuring circuit, and the impedance can be independently at two ends mesh shields layer being formed between by biological tissue and controller housing 9 or contact 2 detects, and not being subject to the impact of the circuit of the other end, this point can realize by analog switch control access break-make or the mode such as amplifier that connects high input impedance.Fig. 7 a and Fig. 7 b have shown according to two kinds of example structure of the present invention.Can judge more reliably the integrity of mesh shields layer 5 by the impedance loop size result of measuring by mesh shields layer 5 two ends more respectively.In the time that mesh shields layer 5 is intact, the impedance loop size detecting by its two ends in theory should be identical, pass through repeated detection, the difference of both meansigma methodss is in a less scope, or carry out assumed statistical inspection and there is no significant difference, and testing result difference when testing result and initial implantation is little, can judge that mesh shields layer 5 is intact, otherwise judge mesh shields layer 5 fault.If there is fault, the impedance loop difference in size relatively detecting from mesh shields layer 5 two ends can further judge the position that fracture occurs, if both detect quite, and the testing result during all apparently higher than initial implantation, show that fracture appears at electrode centre position, as shown in Fig. 7 c-7d; Appear at the position near electrode distal end if far-end testing result higher than near-end testing result, shows to rupture, as shown in Fig. 7 e-7f, vice versa, and difference of them is larger, and fracture position is the closer to mesh shields layer edge.
Fig. 8 a and Fig. 8 b have shown that two kinds can be used for the impedance magnitude measuring circuit of measuring detecting the impedance magnitude in loop in the present invention.
In measuring circuit as shown in Figure 8 a, the A end and B end of measuring circuit accessed respectively at the two ends of detecting loop, with resistance R
1series connection produces dividing potential drop, detects impedance loop size Z
mxvariation make the voltage V of operational amplifier normal phase input end
1also change.The voltage follower of V1 through being made up of operational amplifier, passes through V
obe input to the ADC input of controller 8.V
1changing Pattern be:
Wherein, reference voltage V
refshould be consistent with the ADC reference voltage of controller 8; Resistance R
1the sensitivity that detects of size impact, R
1should be close on the order of magnitude with the impedance magnitude that detects loop.In embodiment as shown in Figure 5, by R
1be decided to be at 1K ohm and be advisable between 10K ohm; In the embodiment as shown in Fig. 6 and Fig. 7 a-7f, by R
1be decided to be at 100K ohm and be advisable between 1M ohm.In the time measuring, can be at V
refthe reference voltage that end input is constant, carries out repeatedly ADC signals collecting and computing, calculates the impedance magnitude Z repeatedly measuring
mxiaverage, be considered as detecting the impedance magnitude Z in loop
mxfinal measured value.
Fig. 8 b has shown the scheme of the impedance magnitude measuring circuit based on another kind of principle.Voltage reference diode D
zwith operational amplifier A
0form a constant-current source, U
zfor voltage reference diode D
zreference voltage, the output current of constant-current source size is i
t=U
z/ R
z.Preferably, select 2.5V voltage reference diode LM336 and 2.5K ohmage R
zcan obtain i
t=U
z/ R
z=1mA.Detect loop as in load impedance access constant-current source, i
tflow into and detect loop through B end, flow through and detect loop and flow back to impedance magnitude measuring circuit by A end.Measure and detect between two ends, loop, be i.e. potential difference Δ V=V between B end and A end
2-V
1, can be by formula Z
mx=Δ V/i
scalculate the impedance magnitude Z detecting between two ends, loop
mx.
Preferably, as shown in Figure 8 b, by three operational amplifier A
1, A
2, A
3can form measuring amplifier, in order to measure the potential difference Δ V between A end and B end.Can be calculated through theory:
V
ocan record by the ADC input that is input to controller:
In the time measuring, can be at V
ccthe reference voltage that end input is constant, carries out repeatedly ADC signals collecting and computing, calculates the impedance magnitude Z repeatedly measuring
mxiaverage, be considered as detecting the impedance magnitude Z in loop
mxfinal measured value.
Than circuit as shown in Figure 8 a, impedance magnitude measuring circuit is as shown in Figure 8 b input to the signal V in controller ADC
oand the relation that detects impedance magnitude between two ends, loop is linear, and can be by changing R
1with R
2resistance adjust the sensitivity of measuring circuit.
Implanted electrode constructed in accordance, can be applied in cardiac pacemaker, defibrillator, brain deep brain stimulation device, spinal cord stimulation device, vagus nerve stimulator, the intestines and stomach stimulator or other similar application.The embodiment rejecting in the present invention is only for explaining and unrestricted claim scope of the present invention to technical scheme of the present invention and inventive concept.All technical staff in the art in conjunction with prior art, test available other technologies scheme by logical analysis, reasoning Huo You county, within also should being considered to drop on claim protection domain of the present invention on the inventive concept basis of this patent.
Claims (10)
1. an implanted electrode, comprise an elongated electrode catheter (1), be furnished with at least one contact (2) at the far-end of described electrode catheter (1), at the near-end of described electrode catheter (1), at least one adapter (3) be set; Described contact (2) is connected by being arranged in inner respectively with one adapter of wire (4) (3) of electrode body (1); Outside described electrode catheter, be furnished with the mesh shields layer (5) that at least one deck is not directly connected with adapter (3) with described contact (2), described mesh shields layer (5) uses the electric good conductor material with biocompatibility to make; The integrity of described mesh shields layer (5) can be detected by controller (8).
2. implanted electrode according to claim 1, is characterized in that, described controller (8) comprises impedance magnitude measuring circuit (10).
3. implanted electrode according to claim 2, is characterized in that, described controller (8) detects the impedance loop size Z that comprises mesh shields layer (5) by impedance magnitude measuring circuit (10)
mx, and with set threshold value Z
mthcompare, work as Z
mxbe greater than Z
mthtime think that mesh shields layer (5) breaks down.
4. implanted electrode according to claim 3, is characterized in that, described threshold value Z
mthset in advance according to priori experience, or controller provides setting Z
mthfunction, when carrying out impedance magnitude measurement after implant into body and setting according to the impedance loop size of actual measurement.
5. implanted electrode according to claim 3, is characterized in that, carries out respectively the measurement of impedance magnitude at far-end and the near-end of mesh shields layer (5).
6. implanted electrode according to claim 5, it is characterized in that, the near-end that the near-end setting of described mesh shields layer (5) can be connected with described controller (8) is brought ring (6) together, or the far-end of described mesh shields layer (5) arranges far-end and brings ring (7) together, be connected with an adapter (3) of near-end by described wire (4), and then can be connected with controller (8).
7. implanted electrode according to claim 5, it is characterized in that, the near-end of described mesh shields layer (5) and far-end arrange respectively that near-end is brought ring (6) together and far-end is brought ring (7) together, described near-end is brought ring (6) together and can be connected with controller (8), described far-end is brought ring (7) together and is connected with an adapter (3) of near-end by wire (4), and then can be connected with controller (8);
Described near-end is brought ring (6) together and is brought ring (7) together with described far-end and be directly connected with described mesh shields layer (5), and the integrity of described mesh shields layer (5) can be brought ring (6) and/or far-end together by near-end and bring ring (7) together and detect.
8. implanted electrode according to claim 3, it is characterized in that, the A end and B end, the resistance R of the impedance in described loop and impedance magnitude measuring circuit (10) of described impedance magnitude measuring circuit (10) accessed respectively at the two ends in described loop
1series connection produces dividing potential drop, impedance loop size Z
mxvariation make the voltage V of operational amplifier normal phase input end
1also change; V
1through the voltage follower being formed by operational amplifier, pass through V
obe input to the ADC input of controller (8); V
1changing Pattern be:
Wherein, reference voltage V
refshould be consistent with the ADC reference voltage of controller (8).
9. implanted electrode according to claim 3, is characterized in that, the A end and B end, the voltage reference diode D of described impedance magnitude measuring circuit (10) of described impedance magnitude measuring circuit (10) accessed respectively at the two ends in described loop
zwith operational amplifier A
0form a constant-current source, U
zfor voltage reference diode D
zreference voltage, the output current of constant-current source size is i
t=U
z/ R
z; Described loop is accessed in constant-current source as load impedance, i
tflow into described loop through B end, the described loop flow back to described impedance magnitude measuring circuit by A end of flowing through; Measure and detect between two ends, loop, be i.e. potential difference Δ V=V between B end and A end
2-V
1, can be by formula Z
mx=Δ V/i
scalculate the impedance magnitude Z detecting between two ends, loop
mx.
10. a medical assembly, is characterized in that, comprises according to the implanted electrode described in any one in claim 1-9.
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104606781A (en) * | 2015-01-19 | 2015-05-13 | 清华大学 | MRI-compatible split implantable medical device |
| CN107335134A (en) * | 2017-08-09 | 2017-11-10 | 北京品驰医疗设备有限公司 | Implantable nerve stimulating electrode |
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| CN110520042A (en) * | 2019-07-17 | 2019-11-29 | 诺尔医疗（深圳）有限公司 | Intracranical deep electrode |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090149920A1 (en) * | 2007-12-06 | 2009-06-11 | Yingbo Li | Leads with high surface resistance |
| US20090198314A1 (en) * | 2008-02-06 | 2009-08-06 | Foster Arthur J | Lead with mri compatible design features |
| CN102186532A (en) * | 2008-10-15 | 2011-09-14 | 皇家飞利浦电子股份有限公司 | Probe for implantable electro-stimulation device |
| CN102824689A (en) * | 2012-09-07 | 2012-12-19 | 清华大学 | Implanted electrode and preparation method thereof and medical assembly comprising implanted electrode |
| CN103269749A (en) * | 2010-10-29 | 2013-08-28 | 美敦力公司 | Improved sensing in an implantable device in the presence of an interfering signal using lead impedance measurements |
| CN103402579A (en) * | 2011-01-21 | 2013-11-20 | 美敦力公司 | Diagnosis of lead fracture and connection problems |
-
2014
- 2014-06-27 CN CN201410307770.0A patent/CN104083823B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090149920A1 (en) * | 2007-12-06 | 2009-06-11 | Yingbo Li | Leads with high surface resistance |
| US20090198314A1 (en) * | 2008-02-06 | 2009-08-06 | Foster Arthur J | Lead with mri compatible design features |
| CN102186532A (en) * | 2008-10-15 | 2011-09-14 | 皇家飞利浦电子股份有限公司 | Probe for implantable electro-stimulation device |
| CN103269749A (en) * | 2010-10-29 | 2013-08-28 | 美敦力公司 | Improved sensing in an implantable device in the presence of an interfering signal using lead impedance measurements |
| CN103402579A (en) * | 2011-01-21 | 2013-11-20 | 美敦力公司 | Diagnosis of lead fracture and connection problems |
| CN102824689A (en) * | 2012-09-07 | 2012-12-19 | 清华大学 | Implanted electrode and preparation method thereof and medical assembly comprising implanted electrode |
Cited By (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104606781B (en) * | 2015-01-19 | 2017-01-04 | 清华大学 | A kind of split implantable medical devices of MRI compatible |
| CN104606781A (en) * | 2015-01-19 | 2015-05-13 | 清华大学 | MRI-compatible split implantable medical device |
| CN107335134A (en) * | 2017-08-09 | 2017-11-10 | 北京品驰医疗设备有限公司 | Implantable nerve stimulating electrode |
| CN109100896A (en) * | 2018-10-08 | 2018-12-28 | 深圳市华星光电技术有限公司 | The vertical light line restorative procedure of array substrate, display panel and its display panel |
| WO2020107944A1 (en) * | 2018-11-26 | 2020-06-04 | 清华大学 | Temperature rise prediction method and apparatus |
| CN110520042A (en) * | 2019-07-17 | 2019-11-29 | 诺尔医疗（深圳）有限公司 | Intracranical deep electrode |
| US20210015391A1 (en) * | 2019-07-17 | 2021-01-21 | Neuroechos Medical (Shenzhen) Co., Ltd | Deep intracranial electrode |
| US11497428B2 (en) * | 2019-07-17 | 2022-11-15 | Neuroechos Medical (Shenzhen) Co., Ltd | Deep intracranial electrode |
| CN110545720A (en) * | 2019-07-17 | 2019-12-06 | 诺尔医疗（深圳）有限公司 | anti-bending intracranial electrode manufacturing method, intracranial deep electrode and electroencephalograph |
| WO2021007815A1 (en) * | 2019-07-17 | 2021-01-21 | 诺尔医疗（深圳）有限公司 | Method for manufacturing bending-resistant intracranial electrode, intracranial depth electrode, and electroencephalograph |
| US20210015429A1 (en) * | 2019-07-17 | 2021-01-21 | Neuroechos Medical (Shenzhen) Co., Ltd | Deep intracranial electrode |
| WO2021007817A1 (en) * | 2019-07-17 | 2021-01-21 | 诺尔医疗（深圳）有限公司 | Deep intracranial electrode |
| CN110691549A (en) * | 2019-07-17 | 2020-01-14 | 诺尔医疗（深圳）有限公司 | Intracranial deep electrode |
| WO2021007818A1 (en) * | 2019-07-17 | 2021-01-21 | 诺尔医疗（深圳）有限公司 | Deep intracranial electrode |
| CN110520042B (en) * | 2019-07-17 | 2022-05-03 | 诺尔医疗（深圳）有限公司 | Intracranial deep electrode |
| CN110691549B (en) * | 2019-07-17 | 2022-07-22 | 诺尔医疗（深圳）有限公司 | Intracranial deep electrode |
| US11497448B2 (en) * | 2019-07-17 | 2022-11-15 | Neuroechos Medical (Shenzhen) Co., Ltd | Deep intracranial electrode |
| CN110716437A (en) * | 2019-10-10 | 2020-01-21 | 中国联合网络通信集团有限公司 | Smart home use method and device |
| CN114847955A (en) * | 2022-07-05 | 2022-08-05 | 诺尔医疗（深圳）有限公司 | Method for manufacturing electroencephalogram and electroencephalogram |
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