CN1133166A - Method and instrument of testing rheoencephalogram by Doppler ultrasonic tech. - Google Patents

Abstract

The present invention provides a kind of method which automatically searches for intracranial blood vessel position along the path of acoustic beam and dynamically indicates the cerebral blood flow attitude of exery space points along the path of acoustic beam and locates the blood vessel position. The principle is that by using Doppler echo signal energy I2+Q2 to indicate the blood flow attitude of space point. It can help the doctor to know rapidly the intracranial blood vessel distribution condition and the blood flow attitude along the the path of acoustic beam pointed by certain detecting head, thus the clinical doctor can conveniently and accurately conduct the blood vessel location and distinguishing, so that the difficulity and time of diagnosis are greatly decreased.

Description

A kind of method and instrument that uses transcranial Doppler sonography technology for detection intracranial brain circular blood stream state to distribute

The present invention relates to a kind of transcranial Doppler sonography cerebrovascular diagnostic system utilizes the ultrasonic and ultrasonic Doppler effect of low frequency pulse wave to detect the method for the distributions of intracranial cerebral blood flow.

In the transcranial doppler technology, the low frequency ultrasound wave impulse of ultrasound probe emission 2MHZ, for the backscattering echo-signal in the brain, determine the depth of scattering source with following formula:

depth＝c·t/2 (1)

Wherein the c speed that to be ultrasound wave propagate at intracranial is got c=1540m/s usually, and t is the time delay between the echo-signal of transmitted pulse and reception.

In existing transcranial doppler (TCD) instrument, only the echo-signal in the sampling volume is carried out analyzing and processing, the degree of depth of sampling volume is set according to (1) formula, usually when starting shooting, instrument sets the initial value of a sampling volume degree of depth, the doctor by rotating probe direction and search blood vessel by the method that keyboard manually changes the degree of depth of sampling volume, because vascularity is in the such three-dimensional space of human brain, concerning the clinicist, searching blood vessel becomes an arduous job, and tool bears the character of much blindness.

The objective of the invention is to overcome the shortcoming of prior art, provide a kind of and searched the intracranial vessel position automatically along beam path, dynamically indication is along the method for the blood flow state distribution of each spatial point of beam path intracranial.

Technical solution of the present invention is: the transcranial Doppler sonography cerebrovascular diagnostic system is by principle of Doppler human body intracranial, cranium outer section blood vessel and show the diagnostic device of shallow blood vessel, its main feature is can check and analysis intracranial trunk hemodynamic parameter, for the diagnosis cerebrovascular disease provides means, this instrument is made of following unit construction: the pulsed wave ultrasound probe, ultrasonic transmit circuit, ultrasound wave receives pre-amplification circuit, high-frequency amplifier circuit, orthogonal demodulation circuit, bandwidth-limited circuit, the range gating circuit, the A/D change-over circuit, governor circuit, analysis of spectrum circuit and IBM PC main frame, the ultrasound echo signal of the hemocyte backscattering in the intracranial vessel is after processing and amplifying, be demodulated to the same phase composition I of doppler echo signal, quadrature phase composition Q, be stored in after A/D is converted to quantity in the two-port RAM, the other end of two-port RAM hangs on the PC bus, the I after the sampling, the Q data are delivered in the initial memory address of IBM PC.

The present invention has increased blood flow state and has detected and indicated (sound window program) module in the system program design of existing transcranial Doppler sonography cerebrovascular diagnostic system, can make the range gating unit in a certain depth bounds, carry out automatic scam, the scope of scanning begins to stopping the degree of depth from ID, with Δ △ is the Dopple ultrasonic echo of each depth point of step pitch, and the method for the invention comprises the steps:

1), sets pulse recurrence frequency; Set sampling volume; Set scan depths;

2), the same phase composition I and the quadrature phase composition Q of this Doppler of degree of depth place echo-signal of sampling, calculate E=I ²+ Q ², be stored in the array 1, repeated sampling also calculates m group data, it is average that m E value made arithmetic, calculate E as the parameter of measurement blood flow state, be stored in the array 2;

3), change the scan depths value, repeat 1 with step-length S millimeter), 2) measurement circulation n (n and S and maximum scan depth d of step _MaxRelevant: n=d _Max/ S), obtain along the blood flow state of an acoustic path n depth point;

4), in the n that an obtains E, search E gets the position of peaked depth point;

5), on display, be depth value with the transverse axis, the longitudinal axis is that E shows the blood flow state along the continuous n of an acoustic path depth location, and respectively with numeral and movably window mark the position that E gets peaked depth point.

6), read key.Before the end of input key, repeat 1)--5) measurement of step and show circulation, dynamically indication is along the variation of the blood flow state of beam path.

In case the input scan end key is set as fathoming of instrument the value of the current position of movable sound window automatically.

The present invention can help the doctor to understand rapidly along intracranial vessel distribution situation and blood flow state in the acoustic path of a certain probe sensing, the clinician can be made things convenient for carry out blood vessel location and identification exactly, greatly reduces diagnosis difficulty and Diagnostic Time.

With reference to accompanying drawing embodiments of the invention are described in detail.

Fig. 1 is the system signal flow chart of used instrument of the present invention.

Fig. 2 is a dynamic scan schematic diagram of the present invention.

Fig. 3 is for realizing the hardware circuit principle figure of dynamic scan.

Fig. 4 is that signal I of the present invention, Q obtain schematic diagram.

Fig. 5 is a program flow diagram of the present invention.

Fig. 6 is a key process chart of the present invention.

Shown in Figure 1 is the ultrasound echo signal flow process of transcranial Doppler sonography cerebrovascular diagnostic system, its principle is: the echo-signal S that probe receives, after prime amplification, high frequency amplification, be divided into two-way, reference signal with same phase (0 °) and quadrature phase (90 °) multiplies each other respectively, and the process low-pass filtering obtains the Doppler frequency shift composition I in the echo again ₁, Q ₁, I ₁, Q ₁Behind elimination blood vessel wall and the PRF composition, under the control of range gating circuit, the doppler echo signal of a certain degree of depth is sampled, sampled data I, Q send in the spectrometer, carry out multiple FFT computing, calculate its frequency spectrum, calculate amplitude spectrum The result sends into IBM PC main frame and further handles and demonstration.

The IBM PC is as the control core of instrument, by writing register manipulation, can change the initial value of enumerator in the control circuit, thereby realize the control of gain of the reception amplifier of the transmitting power of size, scan depths, probe of different pulse recurrence frequencies, sampling volume and instrument.

The present invention has increased blood flow state sound window program module in the program of above-mentioned TCD instrument, make the range gating unit in a certain depth bounds, carry out automatic scam, its principle (is a simplified illustration as shown in Figure 2, in each degree of depth place once sampling): behind the 1st emission trigger impulse, order receives time-delay depth=ID; Behind second emission trigger impulse, time-delay depth ₁=depth+ Δ, behind the 3rd emission trigger impulse, time-delay depth ₂=depth+2 Δ ... by that analogy, depth behind N trigger impulse _N-1=depth+ (N-1) Δ=depth capacity, behind N+1 emission trigger impulse, reverse scan makes depth _N+1=depth+ (N-2) Δ.So periodically scanning repeatedly, sampled point is begun to stopping the degree of depth from ID, is the Dopple echo (I, Q) of each depth point of step pitch with the Δ, shown in figure one dotted line, I, Q signal after the sampling are directly sent in the IBM PC, and with the energy of following formula signal calculated:

E＝I ²＋Q ² (2)

Result calculated E is as the parameter of the blood flow state of weighing certain depth point.

On computer display, be depth value with the transverse axis, the longitudinal axis is that E shows the blood flow state along an acoustic path N depth location, the doctor just can determine according to the size of the E of each depth point whether this degree of depth has blood vessel and endovascular blood flow state.

Fig. 3 is for realizing the hardware circuit principle figure of dynamic scan, depositor 74LS273 (1,2) be coupled on the PC bus, PC CPU operates on it in the mode of writing peripheral port, compose and give 8 digit counters (4,5) counting initial value, enumerator output produces the range gating signal of a certain degree of depth by NAND gate circuit (6,7).Fig. 4 is the schematic diagram that obtains signal I, Q, I, and Q signal is after A/D is converted to digital quantity, the result is stored in the two-port RAM, produce it by address counter and write sequential, the other end of two-port RAM hangs on the PC bus, and the memory address that occupies PC is D800:0000～D800:07FF.

When implementing, consider existing technology platform, realized above-mentioned functions with following method, Fig. 5-Fig. 6 is application flows figure of the present invention, institute of the present invention realization program (being named as window program) with function key ESC activation calls, is pressed esc key as a functional module of TCD instrument system program in sound window module, end sound window module operation returns mastery routine.

After entering window program module, this module is mainly finished following function:

1), obtains along I, the Q-value of the Doppler echo at N on the acoustic path depth location place;

The depth scan scope of setting in this program is optional in 0mm--200mm, and the step pitch Δ that the degree of depth increases (or reducing) is optional in the 2--100mm;

2), calculate the echo-signal of a certain depth point,, M result calculated done sums on average at each depth point sampling M time (getting selection as required within 1～50 time) I, Q-value according to formula (2): $\stackrel{\‾}{E}=\frac{\underset{0}{\overset{M-1}{\mathrm{\Σ}}}{E}_i}{M}-------------\left(3\right)$

Result of calculation E is as the parameter of the blood flow state of weighing this spatial point;

3), after the E value that has obtained N the degree of depth, Automatic Program is found out the depth value of E value correspondence when maximum, and when withdrawing from window module, this value is passed to mastery routine, as the current sampling volume degree of depth, thereby realized searching automatically vascular function;

4), program is the degree of depth with the transverse axis on display screen, the longitudinal axis is a parameters E, be presented at the E value of each depth location, this value reaches the variation of probe orientation in time and dynamically changes, program shows a slip vernier simultaneously, the degree of depth of correspondence when dynamically indicating the E value maximum;

When showing parameters E with vertical coordinate, as show value is fallen within the altitude range of window on the display screen, will do normalized to the E value of calculating, processing method is: $E_{\mathrm{disp}}=\frac{\stackrel{\‾}{E}-\mathrm{EBASE}}{\mathrm{ESCALE}}----------\left(4\right)$

Wherein EBASE is the substrate value, and ESCALE is a proportionality coefficient, because ESCALE can influence E _DlapPace of change, therefore be referred to as sensitivity coefficient.

5), program after whenever finishing once the scanning of pointing to along probe, whether inquiry keyboard has key to press, and presses if any key, turn key handling procedure then, program has defined " ESC " key, presses this key in sound window program, to withdraw from window module, come back to system's mastery routine circulation.

Program has defined " ↑ "/" ↓ " key, is used for changing the EBASE value of (4) formula;

Program has defined " ← "/" → " key, is used for changing the ESCALE value of (4) formula;

Program has defined " HOME "/" END " key, is used to change the transmitting power of probe;

Program has defined " 1 "/" 2 " key, is used to change the gain of the reception amplifier of instrument.

6), in sound window program, the setting of pulse recurrence frequency, the setting of sampling volume, the change of the setting of scan depths value and the transmitting power of probe, the change of the gain of reception amplifier all realizes that by writing corresponding peripheral port depositor the I after the sampling, Q data are delivered in the initial memory address of IBM PC D800.

In the present invention, use the energy I of echo-signal ²+ Q ²The blood flow state of indication spatial point, the calculating of above-mentioned (2) parameter E, desirable

Or it is any with I ²+ Q ²Be basic distortion expression formula; E=I ²+ Q ²I during calculating, Q can be the interior I of the time domain among the figure one, Q signal, also can be through the I behind the fourier-transform ²+ Q ²

Claims (6)

1, a kind of method of using transcranial Doppler sonography technology for detection intracranial brain circular blood stream state to distribute, this method has increased blood flow state and has detected and the instruction program module in the system program of existing transcranial Doppler sonography cerebrovascular diagnostic system, from this program module, read the position of pointing to the also automatic localization of blood vessel of vascularity situation in a certain depth bounds along probe, the method of the invention is characterised in that: make the range gating unit carry out automatic scam in a certain depth bounds, the scope of scanning begins to stopping the degree of depth from ID, with △ is the Dopple ultrasound echo signal of each depth point of step pitch, indicates the blood flow state of spatial point with the energy of echo-signal.

2, a kind of method of using transcranial Doppler sonography technology for detection intracranial brain circular blood stream state to distribute according to claim 1 is characterized in that: the energy E=I of echo-signal ²+ Q ²Expression.

3, a kind of method of using transcranial Doppler sonography technology for detection intracranial brain circular blood stream state to distribute according to claim 1, it is characterized in that: obtain along I, the Q-value of the doppler echo at N on the acoustic path degree of depth place, at M I of each depth point sampling, Q-value, M result calculated done sums on average, and the arithmetic mean of instantaneous value E that is calculated is done normalized.

4, the method for use transcranial Doppler sonography technology for detection intracranial brain circular blood stream state distribution according to claim 2, it is characterized in that: the calculating of parameter E is desirable any with I ²+ Q ²Be basic distortion expression formula, I, Q-value can be I in the time domain, Q signal, also can be through the I behind the fourier-transform ²+ Q ²

5, a kind of method of using transcranial Doppler sonography technology for detection intracranial brain circular blood stream state to distribute according to claim 1, it is characterized in that: the unitary size of range gating can be taken as 0～(stopping the degree of depth-ID) arbitrary value, and the size of step pitch Δ can be taken as the arbitrary value of 0～(stopping the degree of depth-ID)/2.

6, a kind of transcranial Doppler sonography cerebrovascular diagnostic system that is used to measure the distribution of human body brain circular blood stream state, this instrument is made of following unit construction: the pulsed wave ultrasound probe, ultrasonic transmit circuit, ultrasound wave receives pre-amplification circuit, high-frequency amplifier circuit, orthogonal demodulation circuit, bandwidth-limited circuit, the range gating circuit, the A/D change-over circuit, governor circuit, analysis of spectrum circuit and IBM PC main frame is characterized in that: the ultrasound echo signal of the hemocyte backscattering in the intracranial vessel is demodulated to the same phase composition I and the quadrature phase composition Q of doppler echo signal after processing and amplifying, be stored in the two-port RAM after A/D is converted to digital quantity, the other end of two-port RAM hangs on the PC bus, the I after the sampling, the Q data are delivered in the initial memory address of IBM PC.

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