CN1056046A - Inspection and measuring instrument for cerebrovascular function - Google Patents

Abstract

The present invention is a kind of dynamic parameters of cerebral blood vessels non-invasive detector, is made of detection system, data pretreatment, computational analysis system and check and analysis software.Wherein detection system comprises pulse wave detector and blood flow rate detector, and the computational analysis system is a microcomputer, and data pretreatment is the bridge of conversion of signals between detection system and the computer.Check and analysis software is finished the measurement of carotid pulse wave and blood flow rate and the analytical calculation of dynamic parameters of cerebral blood vessels.The present invention is simple in structure, easy to operate, calculating is rapid, with low cost, can be widely used in cerebrovascular physiology, pathological study, clinical diagnosis and control.

Description

Inspection and measuring instrument for cerebrovascular function

The present invention relates to the instrument that a kind of dynamic parameters of cerebral blood vessels noinvasive triage is surveyed.

Dynamic parameters of cerebral blood vessels is the important indicator of reflection cerebrovascular function.It is correct that to detect these parameters significant for the evaluation of cerebrovascular physiology, pathological study, clinical diagnosis and control and therapeutic effect etc.Because cerebrovascular is among the skull encirclement, directly the noinvasive triage is surveyed dynamic parameters of cerebral blood vessels very big difficulty.People try hard to by detecting carotid blood flow parameter, providing cerebral circulation for information about indirectly.The inventor is at " the check and analysis method and the instrument of dynamic parameters of cerebral blood vessels " (application number: 90102812.6) in the patent of invention, once proposed by detecting carotid artery flow waveform q(t) and caliber waveform d(t), utilize the cerebrovascular blood flowing dynamics analytical model of being set up to calculate the method and the corresponding instrument of dynamic parameters of cerebral blood vessels.But because it is bigger to utilize principle of Doppler to detect carotid artery caliber difficulty, cost is higher, has influenced the development and application of this instrument.

The objective of the invention is to propose a kind of by detecting carotid pulsation waveform and flow velocity waveforms, simple in structure, the easy to operate inspection and measuring instrument for cerebrovascular function of calculating dynamic parameters of cerebral blood vessels by to cerebrovascular blood dynamics analysis.

Dynamic parameters of cerebral blood vessels mainly contains following three classes:

(1) the reflection brain circular blood stream state has: blood flow rate V(maximum Vmax, meansigma methods Vm, minima Vmin), mean blood flow Qm.

(2) reflection cerebral blood vessel elasticity state has: characteristic impedance Zc, pulse wave velocity C.

(3) reflection cerebrovascular bed resistance state has: cerebrovascular Peripheral resistance R.

The dynamic parameters of cerebral blood vessels nondistructive detecting method that the present invention proposes, its step is as follows:

(1) the blood flow rate detector is measured carotid artery flow velocity wave form V(t) analogue signal;

(2) measure carotid pulse wave with the pulse wave detector, and demarcate with the measured pressure value of conventional method.Thereby obtain carotid pressure waveform p(t) analogue signal;

(3) calculate dynamic parameters of cerebral blood vessels according to above-mentioned parameter by computer analysis.

The analytical calculation of dynamic parameters of cerebral blood vessels is based on cerebrovascular blood dynamics analysis.Its analysis calculation method is as follows:

1, to carotid pressure p (t) and flow velocity v(t) carry out Fourier and analyze:

Po and Vo are respectively pressure p (t) and flow velocity V(t in the formula) meansigma methods, Pn and Vn are respectively p(t) and the amplitude of nth harmonic v(t), ψ pn is respectively p(t with ψ vn) with v(t) nth harmonic the position mutually, ω is a circular frequency, the number of times that N gets for the Fourier breakdown.

Calculating about the cerebrovascular impedance operator.By the Fourier breakdown, can be able to carotid artery is the cerebrovascular input impedance at top:

Zn＝Pn/Vn

n＝1，2，…，N （2）

ArgZn＝ψpn-ψvn

Attention: above-mentioned input impedance is with pressure p (t) and flow velocity v(t) serve as the basis definition, abbreviate the P-V input impedance as, its unit is Newton-second/rice ^-3

So cerebrovascular characteristic impedance can be represented by the formula into:

$\mathrm{Zc}=\frac{1}{N-2}\underset{n=3}{\overset{N}{\mathrm{\Σ}}}\left|\mathrm{Zn}\right|\left(3\right)$

(N=10,11, or 12)

Cerebral vascular resistance can be expressed from the next into:

R＝Po/Vo （4）

On the other hand, by the relational expression of pulse wave velocity C and characteristic impedance Zc, can get the pulse wave velocity expression formula and be:

C＝ (Zc)/(ρ) （5）

ρ is a density of blood in the formula, is taken as ρ=1.06g/cm usually ³

The mean blood flow expression formula is:

Qm＝ 1/4 πD ²Vm （6）

Common carotid artery caliber wherein

D=a-bA+cH+dW+ePs-fPd-gVm-hVmax-iVmin (7) A here is the age, and H is a height, and W is a body weight, and Ps is a systolic pressure, and Pd is a diastolic pressure.Coefficient a～i utilizes multiple linear regression method to obtain:

For the man:

a＝4.9398，b＝5.1809×10 ^-4，c＝2.1836×10 ^-2，

d＝4.0182×10 ^-4，

e＝1.5648×10 ^-2，f＝6.6006×10 ^-3，g＝2.4005×10 ^-2，

h＝2.9219×10 ^-2，i＝2.1979×10 ^-2（8）

For the woman:

a＝5.3564，b＝-1.3395×10 ^-2，c＝1.2632×10 ^-2，d＝4.8423×10 ^-3

e＝1.2632×10 ^-2，f＝1.0386×10 ^-2，g＝7.5639×10 ^-2，

h＝5.4855×10 ^-3，i＝2.197×10 ^-2（9）

According to the detection method of above-mentioned dynamic parameters of cerebral blood vessels, the present invention has designed corresponding special testing instrument-inspection and measuring instrument for cerebrovascular function.This instrument comprises detection system 1,3 three parts of data pretreatment 2 and computational analysis system (master computer), and is equipped with blood vessel brain function check and analysis software.Its structure as shown in drawings.

Said detecting system comprise be used to detect carotid pulse waveform p(t) pulse wave detector 4 and be used to detect carotid artery flow velocity wave form v(t) supersonic blood speed detector 5.Above-mentioned data pretreatment 2 is bridges of conversion of signals between detection system 1 and the master computer 3, keeps road 8, A/D change-over circuit 9, state-detection control unit 10, intervalometer 11, decoder 12 to form by electrical switch 6, amplification filtering circuit 7, sampling.Wherein data/address bus is arranged as data channel between A/D converter, intervalometer, state-detection control unit and the master computer.Address bus and control bus are arranged between decoder and the master computer, and decoder is by deciphering the signal on master computer address bus and the control bus, for A/D converter, intervalometer, state-detection control unit provide unique address.Intervalometer provides standard sample frequency (generally being decided to be 200HZ) for sampling hold circuit, detects control unit work with this frequency signal synchronous regime simultaneously, and computer is sent into state-detection control unit data and is used to control electrical switch.Electrical switch is sent into the amplification filtering circuit with the detected signal of detection system after selecting (generally deciding amplification is 2, cut-off frequency is the Butterworth low-pass filter circuit of 30HZ), sampling keeps through sampling hold circuit, sends into the A/D change-over circuit then and carries out the A/D conversion.The status signal of detection system (collection/freeze signal of pulse wave and flow speed wave, current meter gain signal) detects the back by the state-detection control unit and sends into master computer by data/address bus.The aforementioned calculation analytical system is a microcomputer.Above-mentioned cerebrovascular check and analysis software comprises detection and analytical calculation two large divisions.Wherein the test section is used for the control detection system, finish patient left and right sides carotid pulse wave p(t) and blood flow velocity wave v(t) measurement of (comprising maximum Vmax, minima Vmin, meansigma methods Vm), the patient can be imported for information about simultaneously: age A, height H, body weight W, systolic pressure Ps, diastolic pressure Pd.Above-mentioned measurement result and patient's information storage are on disk.The computational analysis part is measured the data p(t that obtains to detection system) and v(t) carry out Fourier and analyze, calculate the related parameter that has of cerebrovascular function then: cerebrovascular characteristic impedance Zc, pulse wave velocity C, cerebrovascular Peripheral resistance R and mean blood flow Qm, and deposit the result in disk or printing.These parameter Z c, R, C, Qm are with p(t) and v(t) serve as basis and respectively by aforementioned formula (3), (4), (5), (6) definition.Therefore, master computer is finished the analytical calculation to the cerebrovascular function parameter by calculating analysis software according to formula (1)～(9).

Owing to the present invention is based on detection to carotid pulsation waveform and flow velocity waveforms, avoided detection to carotid artery caliber waveform, thereby many troubles have been avoided, Ding Yi cerebrovascular function parameter based on this, calculate succinct, thereby make the present invention simple in structure, easy to operate, calculate rapidly, cost is more cheap.Can be widely used in cerebrovascular physiology, pathological study, clinical diagnosis and control etc.

In the embodiment detection system of the present invention, pulse wave detects can adopt physiological pressure transducer, and blood flow rate detects the doppler ultrasound blood flow rate instrument that can adopt Fudan University to succeed in developing.Electrical switch can adopt CD4051 in the pretreatment system, the amplification filtering circuit is specifically used μ A741, sampling hold circuit specifically adopts LF398, A/D converter ADC0804, intervalometer adopts 8253, state-detection control unit and decoder adopt Programmable Logic Device, are specially GAL16V8, and it has function of keeping secret preferably.The computational analysis system can adopt IBM series microcomputer.

Accompanying drawing is a structured flowchart of the present invention.

Claims (2)

1, a kind of inspection and measuring instrument for cerebrovascular function is made of detection system 1, data pretreatment 2, computational analysis system (master computer) 3 and cerebrovascular function check and analysis software, it is characterized in that:

(1) check and analysis system comprises the supersonic blood speed detector 5 that is used to detect the pulse wave detector 4 of carotid pulse waveform p (t) and is used to detect carotid artery flow velocity wave form v (t).

(2) data pretreatment is the bridge of conversion of signals between detection system and the master computer, is made up of electrical switch 6, amplification filtering circuit 7, sampling hold circuit 8, A/D converter 9, state-detection control unit 10, intervalometer 11, decoder 12.Wherein data/address bus is arranged as data channel between A/D converter, intervalometer, state-detection control unit and the master computer.Address bus and control bus are arranged between decoder and the master computer, and decoder is by deciphering signal on master computer address bus and the control bus, for A/D converter, intervalometer and state-detection control unit provide unique address.Intervalometer provides the standard sample frequency for sampling hold circuit, simultaneously, detects control unit work with this frequency signal synchronous regime.Electrical switch is sent into the amplification filtering circuit with the detected signal of detection system after selecting, after the sampling hold circuit sampling keeps, send into the A/D change-over circuit and carry out the A/D conversion again.The status signal of detection system (pulse wave and flow speed wave collection/freeze signal, current meter gain signal) detects the back by the state-detection control unit and sends into master computer by data/address bus.

(3) computational analysis system is a microcomputer.

(4) cerebrovascular check and analysis software comprises detection and computational analysis two large divisions:

Test section: be used for the control detection system, finish patient left and right sides carotid pulse wave p (t) and blood flow velocity wave v (t) (are comprised maximum Vmax, minima Vmin, meansigma methods Vm) measurement can be imported the patient for information about simultaneously: age A, height H, body weight W, systolic pressure Ps, diastolic pressure Pd.

The computational analysis part: data p (t) and v (t) that detection system is measured carry out the Fourier analysis, calculate the related parameter that has of cerebrovascular function then: cerebrovascular characteristic impedance Zc, pulse wave velocity C, cerebrovascular Peripheral resistance R and mean blood flow Qm.

2, inspection and measuring instrument for cerebrovascular function according to claim 1 is characterized in that described computational analysis system adopts following formula definition about the cerebrovascular function parameter and calculates:

(1) cerebrovascular characteristic impedance Zc: $\mathrm{Zc}=\frac{1}{N-2}\underset{n=3}{\overset{N}{\mathrm{\Σ}}}\left|\mathrm{Zn}\right|$

N gets 10,11, or 12; Wherein | Zn|=Pn/Vn, n=1,2 ..., N.

Here Pn and Vn are respectively p(t) and Fourier v(t) decompose in the amplitude of nth harmonic.

(2) cerebral vascular resistance R:

R＝Po/Vo

Here Po and Vo are respectively p(t) and meansigma methods v(t).

(3) pulse wave velocity C:

C＝Zc/ρ

Wherein ρ is a density of blood.

(4) mean blood flow Qm:

Qm＝πD ²·Vm/4

Wherein D is the common carotid artery caliber:

D＝a-b·A+c·H+d·W+e·Ps+f·Pd-g·Vm-h·Vmax-i·Vmin

Here A, H, W are respectively age, height, body weight, and Ps, Pd are systolic pressure and diastolic pressure, and Vm, Vmax, Vmin are respectively the meansigma methods of carotid artery flow speed, maximum, minima, and these parameters obtain by measuring.Coefficient a～i is different with the woman according to the man, is obtained by statistical regression analysis.

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