CN105769190A - Device for detecting cephalophyma and encephaledema - Google Patents

Abstract

The invention relates to a device for detecting cephalophyma and encephaledema. The device comprises a microwave swept-frequency signal generator, a sensor, a detector and a parameter analysis system, wherein the microwave swept-frequency signal generator is used for generating a microwave swept-frequency signal; the sensor comprises two coaxial lines and a cylindrical waveguide with two ends open; the swept-frequency signal can enter the waveguide through coupling of one coaxial line, then resonates in the waveguide and is received by the other coaxial line; the detector is used for converting the received microwave swept-frequency signal into an electric signal and amplifying the electric signal; the parameter analysis system calculates the dielectric constant value and the electric conductivity of a brain and evaluates the condition of cephalophyma and encephaledema according to the detected dielectric constant value and the electric conductivity of the brain and the change rate of parameters. The device can be used for continuously monitoring the condition of cephalophyma and encephaledema, distinguishes hemorrhagic stroke from ischemic stroke and has the characteristics that no trauma is caused, the detection precision is high, a warning is sent to a patient with the disease worsened quickly in advance and the like.

Description

A kind of device for cephalophyma, cerebral edema detection

Technical field

The invention belongs to technical field of medical instruments, relate to a kind of device for cephalophyma, cerebral edema detection.

Background technology

On clinical medicine, cerebral hemorrhage and cerebral edema are all the brain diseasess that home and abroad M & M is all significantly high.The reason causing cerebral hemorrhage has a lot, wherein mainly has hypertension, cerebrovascular malformation and cerebral trauma etc..Spontaneous cerebral hemorrhage is one of principal disease threatening middle-aged and elderly people health, and along with the aggravation of aged tendency of population, cerebral hemorrhage more has the trend of explosion type.In cerebral hemorrhage sufferer, hematoma Enlargement in Spontaneous and hemorrhage again be clinical common situation, if amount of bleeding is excessive or bleeding rate is too fast, it is easy to brain to be caused irreversible grievous injury, or even dead.Cerebral edema is to increase to the cerebral disease of feature with moisture in a kind of cerebral tissue, the pathomechanism causing cerebral edema also has a lot, but the cerebral edema no matter which kind of mechanism causes, along with the intensification of cerebral edema, Brain tissue volume increases, intracranial pressure also increases simultaneously, when developing into a certain degree, the infringement in cerebral tissue generating function and structure can be made, as do not diagnosed in time and process, brain will be formed serious harm, even concurrent cerebral hernia, central respiratory and circulatory failure and death.

For clinician, accurately understand cephalophyma patient's bleeding amount increase whether with hematoma Enlargement in Spontaneous situation, or accurately understand the situation that in cerebral edema sufferer brain, moisture increases, for guiding treatment, rescue life and prognosis has very important meaning, therefore a kind of cost is low, and detection method simple to operate, can effectively to continue to detect the cerebral edema state of an illness can improve clinical therapeutic efficacy.

The method clinically detection of various cerebral disorders and characteristic described, mainly multiple Neuroimaging methods, such as CT, nuclear magnetic resonance, NMR and angiography etc., these method Clinical detection images are clear, can accurately judge scope and the degree of instantaneous cephalophyma, but the imaging session time of these methods is short, in the process for the treatment of patient, the understanding of hematoma or edematous state is only CT or MRI focus image when being admitted to hospital, and clinician lacks real-time hematoma in curing patient process, edema develops information.

At present, the technology of other Noninvasive assessmet cephalophymas or cerebral edema, such as the technology such as near-infrared spectrum technique, electrical impedance technology, but the ability that near infrared light and electric current penetrate skull is weak, and precision is not high enough.Other are existing based on electromagnetic transmission detection technique, by contrasting the change penetrating electromagnetic amplitude and phase place before and after brain, owing to electromagnetic wave is when penetrating brain, it may occur that complicated scattering, so the sensitivity of detection is not high yet.

There are some researches show, the relative dielectric constant of alba and grey matter respectively, 39.6 and 53.2, conductivity is 0.41S/m and 0.57S/m respectively.The relative dielectric constant of blood and conductivity are 61.1 and 1.58S/m, and when cerebral hemorrhage blood volume increases hematoma Enlargement in Spontaneous, the dielectric constant of brain and conductivity all can increase.And the relative dielectric constant of moisture is 81, the conductivity of cerebral edema part is 0.66S/m, when cerebral edema expands, the dielectric constant of brain and conductivity also can increase, therefore a kind of apparatus and method that can accurately detect brain dielectric constant and conductivity, the state of an illness of current patents can be reflected accurately, additionally by the speed calculating change of illness state, if when hematoma, edema increase fast especially at short notice, early warning can also be sent in advance, enough times are had to make corresponding treatment strategies to doctor medical personnel, the final effect improving treatment.

Additionally, apoplexy is divided into hemorrhagic apoplexy and cerebral infarction, Therapeutic Method when hemorrhagic apoplexy and cerebral infarction is completely contradicted, at present clinically only etc. sufferer by CT or nuclear magnetic resonance check heel row except patient being carried out corresponding treatment after cerebral hemorrhage, so easily missed the gold period of having treated.Because the dielectric constant of ischemic tissue and conductivity can decline to a great extent, therefore it is badly in need of a kind of apparatus and method that can accurately detect brain dielectric parameter can be placed on ambulance, sufferer is carried out Preliminary detection, distinguish hemorrhagic apoplexy or cerebral infarction, make patient obtain medical treatment in the very first time.

Summary of the invention

In view of this, it is an object of the invention to provide a kind of device for cephalophyma, cerebral edema detection, the cephalophyma of patient and cerebral edema situation can be carried out persistence monitoring by this device, it also is able to hemorrhagic apoplexy or cerebral infarction are made a distinction, and there is hurtless measure, accuracy of detection height, the express patient of aggravation is sent the features such as early warning in advance.

For reaching above-mentioned purpose, the present invention provides following technical scheme:

A kind of device for cephalophyma, cerebral edema detection, this device includes microwave sweep signal source, sensor, cymoscope, parametric analysis system；

Described microwave sweep signal source is used for producing microwave sweep signal；

Described sensor is made up of the column type waveguide of two coaxial lines and both ends open, and swept-frequency signal can be coupled into waveguide by coaxial line, then resonates in waveguide, another root coaxial line receive signal；

Described cymoscope is for converting the microwave sweep signal received to the signal of telecommunication and being amplified；

Described parametric analysis system, for the result of the amplitude respective frequencies that detection obtains is processed, obtains resonant frequency f and the loaded quality factor Q of resonance crest_L, then calculate dielectric constant values and the conductivity of brain, and according to detecting the brain dielectric constant values and conductivity that obtain, and the rate of change of parameter, the state of an illness of cephalophyma and cerebral edema is estimated.

Further, it is L-type that the inner wire of described coaxial line extends into the part of waveguide, and its total length b >=20 millimeter enable microwave to be effectively coupled into column type waveguide.

Further, part between waveguide and brain, being provided with a sack equipped with semi-solid matched media material, described matched media material adopts gelatin, polyethylene, sodium dehydroacetate and water to mix, and the dielectric constant of described matched media is suitable with the dielectric constant of skin.

Further, the microwave sweep signal of described microwave sweep signal source ranges for 100MHz to 400MHz.

Further, described parametric analysis system passes through the below equation relative dielectric constant ε to brain_rIt is calculated

${\mathrm{\ϵ}}_r=\frac{\{{\left(\frac{c}{2{\mathrm{\πf}}_{nml}}\right)}^2\[{\left(\frac{p_{nm}^{\′}}{a}\right)}^2+{\left(\frac{l\mathrm{\π}}{d}\right)}^2\]V_0-V_m{\mathrm{\ϵ}}_{rm}\}}{(V_0-V_m)}$

In formula, c is the speed of vacuum light, f_nmlFor resonant frequency, p '_nmJ ' after counting is sought for n rank Bessel function_n(p_nmThe m-th root of)=0, a is the internal diameter of column type waveguide, and d is the length of column type waveguide, V_oFor total volume of column type waveguide, V_mFor the volume of matched media, ε in column type waveguide_rmFor the relative dielectric constant of matched media in column type waveguide.

Further, the conductivity σ of brain is calculated by parametric analysis system by below equation

$\mathrm{\σ}={\mathrm{\Γ}}_1{\mathrm{\ϵ}}_0{\mathrm{\ϵ}}_r\mathrm{\ω}\[\frac{{\mathrm{\σ}}_1}{{\mathrm{\Γ}}_2{\mathrm{\ϵ}}_0{\mathrm{\ϵ}}_{r1}\mathrm{\ω}}-(\frac{1}{{\mathrm{\Γ}}_2{Q}_{L1}}-\frac{1}{{\mathrm{\Γ}}_2{Q}_{L2}})\]$

In formula, Γ₁For microwave from the reflection coefficient injected with reference to sample during air；ε₀The dielectric constant of vacuum, its numerical value is 8.854 × 10^-12F/m；ω is angular frequency；Γ₂For microwave from detected object inject air time reflection coefficient；σ₁And ε_r1The respectively known conductivity with reference to sample and relative dielectric constant；Q_L1And Q_L2Loaded quality factor when respectively detection is with reference to sample and measurand, its computing formula is Q_L=f₀/ BW, f₀For resonant frequency, BW is half-power frequency bandwidth.

The beneficial effects of the present invention is: cephalophyma of the present invention, cerebral edema detecting device accuracy of detection are high, less costly；Patient can be carried out the monitoring of persistence by this device, reflects the state of an illness in time, and change of illness state speed is very fast, it may occur however that seriously ill patient sends early warning in advance；This device can be placed on ambulance, and Patients with Apoplexy After detects, and distinguishes cerebral infarction and hemorrhagic apoplexy, allows patient be treated accordingly the very first time.

Accompanying drawing explanation

In order to make the purpose of the present invention, technical scheme and beneficial effect clearly, the present invention provides drawings described below to illustrate:

Fig. 1 is the structural representation of detecting device of the present invention；

Fig. 2 is the schematic diagram in kind of the present invention.

Detailed description of the invention

Below in conjunction with accompanying drawing, the preferred embodiments of the present invention are described in detail.

The invention provides a kind of device for cephalophyma, cerebral edema detection, for detecting the dielectric constant of measurand, described device is made up of microwave sweep signal source, sensor, detector, parametric analysis system.Design coaxial line Coupled Circle column type waveguide is as Sensor section, and whole brain can be covered by large-sized column type waveguide, even if microwave signal, at hematoma, edema place, scattering occurs, also all can be detected by this sensor.Fill with matched media between brain and waveguide, reduce microwave reflection between cerebral tissue and Air Interface.Microwave is coupled into waveguide by coaxial line, and resonates in waveguide, and when intracerebral hematoma or edema change, corresponding skew also can occur its resonant frequency f, and the shape of resonance crest also can change.Therefore, it is possible to calculated the dielectric constant of brain by resonant frequency f, calculate the conductivity of brain by the loaded quality factor of the crest that resonates, and then reflection cephalophyma or the current concrete state of an illness of cerebral edema.The features such as this detection method accuracy of detection is high, cost is low, simple to operate, it is possible to for the Preliminary detection of cephalophyma, cerebral edema, it is also possible in clinical monitoring, improve clinical therapeutic efficacy.

Cerebral edema detecting device of the present invention have employed following principle: the relative dielectric constant of alba and grey matter respectively, 39.6 and 53.2, conductivity is 0.41S/m and 0.57S/m respectively.The relative dielectric constant of blood and conductivity are 61.1 and 1.58S/m, and the dielectric parameter value of blood is far longer than the meansigma methods of brain, and when cerebral hemorrhage blood volume increases hematoma Enlargement in Spontaneous, the dielectric constant of brain and conductivity all can increase；And the relative dielectric constant of moisture is 81, the conductivity of cerebral edema part is 0.66S/m, and when cerebral edema expands, the dielectric constant of brain and conductivity also all can increase；And for cerebral infarction, when blood vessel blockage, the amount of blood supply of brain portion of tissue reduces, the dielectric constant of brain and conductivity can substantially reduce.Therefore by the dielectric constant of detection brain and conductivity and situation of change thereof, it is possible to realize the assessment to cephalophyma and cerebral edema change of illness state, difference cerebral infarction or hemorrhagic apoplexy.Detecting device of the present invention formally designs according to principles above, according to the electromagnetic theory that column type waveguide is relevant, derives the computing formula of brain dielectric constant and conductivity, and then obtains the situation within brain.

Fig. 1 is the structural representation of detecting device of the present invention, as it can be seen, this detecting device, including microwave sweep signal source, sensor, detector, parametric analysis system；Sensor is formed by coaxial line and column type waveguide.

Microwave sweep signal source produces microwave sweep signal, it is coupled into waveguide by coaxial line, and resonate in waveguide, being received signal by another root coaxial line, and deliver to cymoscope, cymoscope converts the microwave sweep signal received to the signal of telecommunication and is amplified, parametric analysis system, the result of the amplitude respective frequencies detected is processed, obtains resonant frequency f and the loaded quality factor Q of resonance crest_L, then calculate dielectric constant values and the conductivity of brain and the rate of change of parameter and then the pathological changes situation in reflection brain.

Its concrete computational methods are as follows:

Parametric analysis system passes through the below equation relative dielectric constant ε to brain_rIt is calculated

${\mathrm{\ϵ}}_r=\frac{\{{\left(\frac{c}{2{\mathrm{\πf}}_{nml}}\right)}^2\[{\left(\frac{p_{nm}^{\′}}{a}\right)}^2+{\left(\frac{l\mathrm{\π}}{d}\right)}^2\]V_0-V_m{\mathrm{\ϵ}}_{rm}\}}{(V_0-V_m)}$

In formula, c is the speed of vacuum light, f_nmlFor resonant frequency, p '_nmJ ' after counting is sought for n rank Bessel function_n(p_nmThe m-th root of)=0, a is the internal diameter of column type waveguide, and d is the length of column type waveguide, V_oFor total volume of column type waveguide, V_mFor the volume of matched media, ε in column type waveguide_rmFor the relative dielectric constant of matched media in column type waveguide.

The conductivity σ of brain is calculated by parametric analysis system by below equation.

$\mathrm{\σ}={\mathrm{\Γ}}_1{\mathrm{\ϵ}}_0{\mathrm{\ϵ}}_r\mathrm{\ω}\[\frac{{\mathrm{\σ}}_1}{{\mathrm{\Γ}}_2{\mathrm{\ϵ}}_0{\mathrm{\ϵ}}_{r1}\mathrm{\ω}}-(\frac{1}{{\mathrm{\Γ}}_2{Q}_{L1}}-\frac{1}{{\mathrm{\Γ}}_2{Q}_{L2}})\]$

In formula, Γ₁For microwave from the reflection coefficient injected with reference to sample during air；ε₀The dielectric constant of vacuum, its numerical value is 8.854 × 10^-12F/m；ω is angular frequency；Γ₂For microwave from detected object inject air time reflection coefficient；σ₁And ε_r1The respectively known conductivity with reference to sample and relative dielectric constant；Q_L1And Q_L2Loaded quality factor when respectively detection is with reference to sample and measurand.

In the present embodiment, the swept-frequency signal that microwave sweep signal source produces ranges for 100MHz to 400MHz, to ensure that column type waveguide can be operated in TE₁₁₁Under pattern, and microwave signal can be good at penetrating cerebral tissue.

Improving as one, it is L-type that the inner wire of coaxial line extends into the part of waveguide, its total length b >=20 millimeter, enables microwave to be effectively coupled into column type waveguide.

Another kind of improvement as the present embodiment, part between waveguide and brain, it is provided with a sack equipped with semi-solid matched media material, described matched media material adopts gelatin, polyethylene, sodium dehydroacetate and water to mix, and the dielectric constant of described matched media is suitable with the dielectric constant of skin.Fig. 2 is the schematic diagram in kind of the present invention.

What finally illustrate is, preferred embodiment above is only in order to illustrate technical scheme and unrestricted, although the present invention being described in detail by above preferred embodiment, but skilled artisan would appreciate that, in the form and details it can be made various change, without departing from claims of the present invention limited range.

Claims (6)

1. the device for cephalophyma, cerebral edema detection, it is characterised in that: this device includes microwave sweep signal source, sensor, cymoscope, parametric analysis system；

Described microwave sweep signal source is used for producing microwave sweep signal；

Described sensor is made up of the column type waveguide of two coaxial lines and both ends open, and swept-frequency signal can be coupled into waveguide by coaxial line, then resonates in waveguide, another root coaxial line receive signal；

Described cymoscope is for converting the microwave sweep signal received to the signal of telecommunication and being amplified；

Described parametric analysis system, for the result of the amplitude respective frequencies that detection obtains is processed, obtains resonant frequency f and the loaded quality factor Q of resonance crest_L, then calculate dielectric constant values and the conductivity of brain, and according to detecting the brain dielectric constant values and conductivity that obtain, and the rate of change of parameter, the state of an illness of cephalophyma and cerebral edema is estimated.

2. a kind of device for cephalophyma, cerebral edema detection according to claim 1, it is characterized in that: it is L-type that the inner wire of described coaxial line extends into the part of waveguide, its total length b >=20 millimeter, enable microwave to be effectively coupled into column type waveguide.

3. a kind of device for cephalophyma, cerebral edema detection according to claim 1, it is characterized in that: the part between waveguide and brain, it is provided with a sack equipped with semi-solid matched media material, described matched media material adopts gelatin, polyethylene, sodium dehydroacetate and water to mix, and the dielectric constant of described matched media is suitable with the dielectric constant of skin.

4. a kind of device for cephalophyma, cerebral edema detection according to claim 1, it is characterised in that: the microwave sweep signal of described microwave sweep signal source ranges for 100MHz to 400MHz.

5. a kind of device for cephalophyma, cerebral edema detection according to claim 1, it is characterised in that: described parametric analysis system passes through the below equation relative dielectric constant ε to brain_rIt is calculated

${\mathrm{\ϵ}}_r=\frac{\{\left(\frac{c}{2{\mathrm{\πf}}_{nml}}\right)\[{\left(\frac{p_{nm}^{\′}}{a}\right)}^2+{\left(\frac{l\mathrm{\π}}{d}\right)}^2\]V_0-V_m{\mathrm{\ϵ}}_{rm}\}}{(V_0-V_m)}$

In formula, c is the speed of vacuum light, f_nmlFor resonant frequency, p ＇_nmJ ＇ after counting is sought for n rank Bessel function_n(p_nmThe m-th root of)=0, a is the internal diameter of column type waveguide, and d is the length of column type waveguide, V_oFor total volume of column type waveguide, V_mFor the volume of matched media, ε in column type waveguide_rmFor the relative dielectric constant of matched media in column type waveguide.

6. a kind of device for cephalophyma, cerebral edema detection according to claim 1, it is characterised in that: the conductivity σ of brain is calculated by parametric analysis system by below equation

$\mathrm{\σ}={\mathrm{\Γ}}_1{\mathrm{\ϵ}}_0{\mathrm{\ϵ}}_r\mathrm{\ω}\[\frac{{\mathrm{\σ}}_1}{{\mathrm{\Γ}}_2{\mathrm{\ϵ}}_0{\mathrm{\ϵ}}_{r1}\mathrm{\ω}}-(\frac{1}{{\mathrm{\Γ}}_2{Q}_{L1}}-\frac{1}{{\mathrm{\Γ}}_2{Q}_{L2}})\]$

In formula, Γ₁For microwave from the reflection coefficient injected with reference to sample during air；ε₀The dielectric constant of vacuum, its numerical value is 8.854 × 10^-12F/m；ω is angular frequency；Γ₂For microwave from detected object inject air time reflection coefficient；σ₁And ε_r1The respectively known conductivity with reference to sample and relative dielectric constant；Q_L1And Q_L2Loaded quality factor when respectively detection is with reference to sample and measurand, its computing formula is Q_L=f₀/ BW, f₀For resonant frequency, BW is half-power frequency bandwidth.