A magnetic nanoparticle-enhanced magnetic induction system for detecting hemorrhagic stroke

Abstract

The application claims a kind of based on magnetic nano particle enhanced magnetic induction hemorrhagic cerebral apoplexy detection system, belong to biomedical engineering field cerebral disease detection and monitoring and physiological signal detection field, it includes: signal source, power amplifier, series resonance circuit, receiving coil, excitation coil, acquisition card and computer, wherein, the signal source is connected with power amplifier, the power amplifier is connected with series resonance circuit, the series resonance circuit is connected with receiving coil and excitation coil respectively, the receiving coil is connected with acquisition card, and the acquisition card is connected with computer;The application includes hardware series resonance circuit design, MAXWELL simulation coil design and helmholtz coil production, hardware system building and experimental test.The application proposes a kind of with high sensitivity can bed-side monitoring system, timely detection cerebral hemorrhage, and it has important significance for the discrimination of cerebral apoplexy type and related cerebral disease monitoring.

Description

Technical Field

[0001] This invention belongs to the field of brain disease detection and monitoring and physiological signal detection in the field of biomedical engineering. Specifically, it is a magnetic induction hemorrhagic stroke lesion detection system based on magnetic nanoparticle enhancement. Background Technology

[0002] Changes in the mechanical functions of cranial tissues contain abundant electromagnetic properties, and hemorrhagic stroke and other conditions will cause alterations in these properties. Electromagnetic-based methods are characterized by portability, non-contact, low cost, and rapid detection. Changes in the electromagnetic properties of the cranium provide important detection and monitoring information for the early detection and intervention of hemorrhagic stroke, and the detection of electromagnetic properties provides an important new means for non-invasive bedside detection.

[0003] Magnetic iron oxide nanoparticles (SPIONs) are superparamagnetic. When excited by an alternating magnetic field, SPIONs are prone to nonlinear magnetization response. Therefore, by using an alternating magnetic field with a specific frequency and sufficiently high amplitude to excite the particles, the magnetic nanoparticles generate a super strong magnetization signal in the alternating magnetic field of magnetic induction detection, making it possible to enhance the sensitivity of magnetic induction detection using magnetic nanoparticles.

[0004] CN113791372A discloses a spatial positioning device and method for magnetic nanoparticles. This detection method is primarily used for real-time scanning imaging of the concentration of magnetic nanoparticles in a analyte. However, the correlation between the detection of magnetic nanoparticle concentration and the detection of physiological signals has not been demonstrated, and the clinical application of this detection method has not been described in detail. The detection system in this invention is a portable bedside device capable of real-time and stable monitoring of cerebral hemorrhage in rabbits. Summary of the Invention

[0005] This invention aims to solve the problems of the prior art. It proposes a magnetic induction-based hemorrhagic stroke detection system enhanced by magnetic nanoparticles. The technical solution of this invention is as follows:

[0006] A magnetic induction hemorrhagic stroke detection system based on magnetic nanoparticle enhancement includes: a signal source, a power amplifier, a series resonant circuit, a receiving coil, an excitation coil, a data acquisition card, and a computer. The signal source is connected to the power amplifier, the power amplifier is connected to the series resonant circuit, the series resonant circuit is connected to both the receiving coil and the excitation coil, the receiving coil is connected to the data acquisition card, and the data acquisition card is connected to the computer.

[0007] The signal source generates an alternating voltage at a specific frequency required by the excitation coil. The power amplifier amplifies the voltage signal on the detection coil. A series resonant circuit is connected to the Helmholtz coil, bringing it into resonance. This circuit enables the Helmholtz coil to generate a stronger alternating magnetic field at its resonant frequency, improving magnetic field detection efficiency. The Helmholtz coil, a symmetrical cancellation coil, is used to cancel interference signals and facilitate the detection of magnetic induction signals. The excitation coil, also a Helmholtz coil, emits the alternating magnetic field. The acquisition card is a dual-channel data acquisition card used to acquire the output signals from both the receiving and excitation coils. A computer performs digital conversion on the analog signals from the receiving and excitation coils, then performs a Discrete Fourier Transform on the digital signals, calculates the phase of the two signals, and finally obtains the phase difference.

[0008] Furthermore, the design of the series resonant circuit specifically includes:

[0009] In an RLC circuit, the circuit impedance is:

[0010]

[0011] Where ω is the angular frequency, R is the resistance, L is the inductance, and C is the capacitance;

[0012] When the circuit resonates:

[0013]

[0014] again

[0015] ω=2πf (3)

[0016] Therefore, the resonant frequency f is:

[0017]

[0018] Furthermore, the power amplifier is a LYB-5040 type AC power amplifier.

[0019] Furthermore, the excitation coil is a specific Helmholtz coil that integrates magnetic nanoparticles with magnetic induction detection technology and is designed and fabricated using Maxwell simulation software, and the receiving coil uses a symmetrical cancellation coil as the receiving coil.

[0020] The advantages and beneficial effects of this invention are as follows:

[0021] The purpose of this invention is to overcome the problems of poor stability and low sensitivity of existing magnetic induction brain hemorrhage detection systems, and to propose a magnetic induction hemorrhagic stroke lesion detection system based on magnetic nanoparticle enhancement.

[0022] The key technical solution of this invention is as follows:

[0023] A magnetic induction-based hemorrhagic stroke lesion detection system enhanced by magnetic nanoparticles includes: a series resonant circuit, a Helmholtz excitation coil, and a symmetrical cancellation receiving coil, with the specific structure as follows:

[0024] The series resonant circuit described above can detect cerebral hemorrhage in rabbits at a specific resonant frequency, thus improving the problem that existing low-frequency band circuits cannot detect it.

[0025] The Helmholtz coil enables the detection of strong signals in the region of the rabbit brain.

[0026] The symmetrical cancellation coil removes interference signals from the detected signal. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the connection of a magnetic induction hemorrhagic stroke detection system based on magnetic nanoparticle enhancement, according to a preferred embodiment of the present invention.

[0028] Figure 2 This is a magnetic field distribution diagram of the excitation coil;

[0029] Figure 3 This is a schematic diagram showing the changes in the MIPS signal after adding different solutions to a magnetic induction coil.

[0030] Figure 4 This is a schematic diagram showing the changes in MIPS over 18 minutes in a rabbit autologous blood bleeding model from the control group.

[0031] Figure 5 This is a schematic diagram showing the changes in MIPS over 18 minutes after 2 mL of blood loss in the experimental group. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of the present invention.

[0033] The technical solution of the present invention to solve the above-mentioned technical problems is:

[0034] Preferred, such as Figure 1 As shown, a magnetic induction hemorrhagic stroke detection system based on magnetic nanoparticle enhancement includes: a signal source, a power amplifier, a series resonant circuit, a receiving coil, an excitation coil, a data acquisition card, and a computer. The signal source is connected to the power amplifier, the power amplifier is connected to the series resonant circuit, the series resonant circuit is connected to the receiving coil and the excitation coil, the receiving coil is connected to the data acquisition card, and the data acquisition card is connected to the computer.

[0035] The signal source generates an alternating voltage at a specific frequency required by the excitation coil. The power amplifier amplifies the voltage signal on the detection coil. A series resonant circuit is connected to the Helmholtz coil, bringing it into resonance. A symmetrical cancellation coil, used to generate a stronger alternating magnetic field at the resonant frequency, is used to cancel interference signals and facilitate the detection of magnetic induction signals. The excitation coil, also a Helmholtz coil, emits the alternating magnetic field. The acquisition card is a dual-channel data acquisition card used to acquire the output signals from the receiving and excitation coils. A computer performs digital conversion on the analog signals from the receiving and excitation coils, then performs a Discrete Fourier Transform on the digital signals, calculates the phase of the two signals, and finally obtains the phase difference.

[0036] (1) Series resonant circuit design, determining the resonant frequency as the excitation frequency. When the circuit achieves series resonance, the total impedance is at its minimum, approximately equal to the pure resistance, and a large current can be generated by providing a small voltage. The advantages of the capacitor in the series resonant circuit are low loss, small high-frequency characteristics, and small equivalent resistance. The power amplifier is a LYB-5040 AC power amplifier, connecting the current and the coil in series.

[0037] In an RLC circuit, the circuit impedance is:

[0038]

[0039] Where ω is the angular frequency, R is the resistance, L is the inductance, and C is the capacitance.

[0040] When the circuit resonates:

[0041]

[0042] again

[0043] ω=2πf (3)

[0044] Therefore, the resonant frequency f is:

[0045]

[0046] The resonant frequency is obtained based on the measured LC value.

[0047] (2) Simulation Circuit Design

[0048] Electromagnetic simulation of the coil was performed using Maxwell software. A Helmholtz coil was designed based on the dimensions of a rabbit's head. Each coil, including the wall thickness, is 5.5mm high, with a 64mm central support sheet (the three support points are evenly spaced at the halfway point). Two sets of coils are wound with a single wire. Two slots are cut into the upper and lower frames. After one set of leads is wound, it passes through the upper frame and exits as a lead wire, which is then soldered with a high-temperature conductor. Finally, the field strength of the excitation coil was tested using a field strength tester to verify the coil's suitability. Figure 2 The diagram shows the magnetic field distribution of the coil.

[0049] (3) Design a Helmholtz coil based on the size of a rabbit's head. Each coil, including the wall thickness, is 5.5 mm high, with a 64 mm support in the middle, made into a sheet shape. Two sets of coils are wound around it. The two frames have two slots, one above the other. After one set of leads is wound, it passes through the upper frame and then exits with a high-temperature wire. Finally, the field strength of the excitation coil is tested using a field strength tester.

[0050] (4) A novel detection system based on magnetic nanoparticle enhancement was constructed, and the magnetic induction phase shift was detected by a multi-channel physiological signal acquisition instrument. The physical experimental detection results were good, and the system stability and sensitivity were greatly improved.

[0051] (5) Results of the physical experiment

[0052] like Figure 4 As shown, through physical experiments involving the sequential addition of 2 ml of a mixture of rabbit blood and magnetic nanoparticles, arterial blood, and magnetic nanoparticle solution to our constructed magnetic induction system, the experimental results show that the content of magnetic nanoparticles is a key factor affecting the MIPS signal. The more magnetic nanoparticles added, the more obvious the change in the MIPS signal. Magnetic nanoparticles have the ability to enhance the detection sensitivity of MIPS. Magnetic nanoparticles enhance the detection system, resulting in high stability and high sensitivity.

[0053] (6) Animal experiment results

[0054] like Figure 5 The graph shows the changes in MIPS over 18 minutes in a rabbit autologous blood bleeding model.

[0055] Experiments were conducted by sequentially adding 2 mL of arterial blood, a mixture of magnetic nanoparticles and autologous blood to our constructed magnetic induction system. The results showed that the MIPS signal of the mixture changed significantly compared with the control group, indicating that magnetic nanoparticles can enhance the sensitivity of magnetic induction detection.

[0056] Animal experimental protocol

[0057] A rabbit brain hemorrhage model was used, and 3 mL of arterial blood from the ear was collected. A hole was drilled in the skull to separate the periosteum, exposing the "cross suture." Using the intersection of the cross suture as the origin, the hole was drilled 6 mm to the left along the coronal suture and then 1 mm posteriorly along the sagittal suture. A 0.7 mm diameter needle was inserted into the brain to a depth of 13 mm and secured with dental cement and 502 glue to prevent dislodgement. The rabbit's head was placed within a magnetic induction coil, and 2 mL of femoral artery blood or a mixture was injected via an infusion pump. The total injection time was 6 minutes, monitored for 6 minutes before injection, 6 minutes during injection, and 6 minutes after injection, for a total monitoring time of 18 minutes before the program was closed. The control group received 2 ml of autologous blood, while the experimental group received 2 ml of a mixture of autologous blood and magnetic nanoparticles.

[0058] like Figure 4 and Figure 5 As shown, Figure 4 This is a graph showing the results of the control group in an animal experiment; Figure 5 This is a diagram showing the results of the animal experiment group.

[0059] (1) The innovative combination of magnetic nanoparticles and magnetic induction detection technology allows magnetic nanoparticles to generate a strong magnetization signal in an alternating magnetic field, thereby enhancing the sensitivity of magnetic induction detection of cerebral hemorrhage.

[0060] (2) By using a series resonant circuit, a magnetic induction detection with strong stability was achieved at a specific resonant frequency.

[0061] (3) Improves the problem that the existing low-frequency band cannot be detected, and enhances the stability and safety of intracranial hemorrhage detection.

[0062] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions.

[0063] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0064] The above embodiments should be understood as illustrative only and not as limiting the scope of protection of the present invention. After reading the description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims

1. A magnetic induction-based hemorrhagic stroke detection system enhanced by magnetic nanoparticles, characterized in that, include: The system includes a signal source, a power amplifier, a series resonant circuit, an excitation coil, a receiving coil, a data acquisition card, and a computer. The signal source is connected to the power amplifier, the power amplifier is connected to the series resonant circuit, the series resonant circuit is connected to both the receiving coil and the excitation coil, the receiving coil is connected to the data acquisition card, and the data acquisition card is connected to the computer. The signal source generates an alternating voltage at a specific frequency required by the excitation coil. The power amplifier amplifies the voltage signal on the detection coil. A series resonant circuit is connected to the Helmholtz coil to put the Helmholtz coil in a resonant state, which is used to make the Helmholtz coil generate a stronger alternating magnetic field at the resonant frequency. The receiving coil is a symmetrical cancellation coil used to cancel interference signals and make it easier to detect magnetic induction signals. The excitation coil is a Helmholtz coil used to emit an alternating magnetic field. The acquisition module is a dual-channel data acquisition card used to acquire the output signals of the receiving coil and the excitation coil. The computer is used to perform digital conversion on the analog signals of the receiving coil and the excitation coil, then perform discrete Fourier transform on the digital signals, and then calculate the phase of the two signals to finally obtain the phase difference. The excitation coil is a specific Helmholtz coil designed and fabricated using Maxwell simulation software, which integrates magnetic nanoparticles with magnetic induction detection technology. The receiving coil uses a symmetrical cancellation coil as the receiving coil.

2. The magnetic induction hemorrhagic stroke detection system based on magnetic nanoparticle enhancement according to claim 1, characterized in that, The design of the series resonant circuit specifically includes: In an RLC circuit, the circuit impedance is: (1) Where ω is the angular frequency, R is the resistance, L is the inductance, and C is the capacitance. When the circuit resonates: (2) again (3) Therefore, the resonant frequency f is: (4)。 3. The magnetic induction hemorrhagic stroke detection system based on magnetic nanoparticle enhancement according to claim 1, characterized in that, The power amplifier is a LYB-5040 AC power amplifier.

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