SU1389755A1 - Apparatus for measuring the thickness of posterior wall of left ventricle - Google Patents

Abstract

The invention is intended for cardiology. The purpose of the invention is to automate dynamic measurements and record the thickness of the posterior wall of the left ventricle of the heart in real time. The device contains a generator 1, ultrasound probe, receiver 3, indicator 4, video amplifier 5, emitter follower 6, key 7, endocardial echo extraction unit 8, first switch 9, integrator 10, amplifier 11, recorder 12, epicardial echo extraction unit 13 -signal, second switch 14, switch 16, inverter 17, clock generator 18, gate driver 19, calibrator 20, first 21 and second 22 normalizing elements, first 23 and second 24 comparators, drivers 25, 26 and triggers 27, 28. Block 15 control is designed to estimate the coe cient gain normalizing the first and second elements. The device makes it possible to compare the amplitudes of the curve of the change in the thickness of the posterior wall of the left, the bulb at a given point of the cardiac cycle with the amplitude of the calibration signal. 1 h. item f-ly, 2 ill. cl

Description

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The invention relates to medical diagnostic equipment and can be used in ultrasound (US) echocardiographs.

The purpose of the invention is to automate dynamic measurements and record the thickness of the posterior wall of the left ventricle of the heart in real time.

FIG. 1 shows a block diagram of the device; in fig. 2 is a time diagram of voltages at the characteristic points of the device circuit.

A device for measuring the thickness of the posterior wall of the left ventricle of the heart (LSL) contains a generator 1, an ultrasonic probe 2, a receiver 3, an indicator 4, a video amplifier 5, an emitter follower 6, a key 7, an endocardial echo extraction unit 8, the first switch 9, an integrator 10, amplifier 11, recorder 12, epicardial echo separation unit 13, second switch 14, control unit 15, switch 16, inverter 17, clock generator 18, gate driver 19, calibrator 20, first 21 and second 22 normalizing elements, first 23 and second 24 comparator The first 25 and second 26 conditioners, the first 27 and second 28 flip-flops 28.

The control unit 15 is designed to control the magnitude of the gain of the first 21 and second 22 normalizing elements, and an oscilloscope of the C1-74 type can be used for this purpose.

The calibrator 20 can be performed on standard logic elements, provides calibration of the recorder 12, for example, H 338-4P signal, the duration corresponding to the thickness of the wall of the ventricle of the heart.

The device works as follows. The synchronous generator 18 generates pulses with a 1320 Hz following frequency (Fig. 26), which ensures the start of the generator 1, which generates the excitation pulses of the ultrasonic probe 2 with a duration of 1 -1.5 µs. At the same time, ultrasound pulses are emitted into the precardial area of the patient (Fig. 2a), are reflected from the heart structures and again arrive at the ultrasound probe 2 and are further processed by the receiver 3 and the video amplifier 5. From the output of the video amplifier 5 (Fig. 2d) the signal goes to the indicator 4 to display the echo cardiogram in the M mode,

The sync pulse generator 18 (Fig. 26) also enters the gate generator 19, where a strobe pulse (Fig. 2c) of adjustable duration / is produced, delayed relative to the sync pulse for an adjustable time interval T.

The parameters t T are set so that the position of the strobe pulse corresponds to the position of the echo signal ZLZH, the driver 19 of the strobe also produces a pulse

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adjustable duration T, which is fed to the calibrator 20 (Fig. 28). The strobe pulse enters the control input of the key 7, to the input of which the echo-signal of the video amplifier 5 is fed through a matching 6 emitter follower 6. The key 6 transmits only the SLEC echo signals (Fig. 2) to the inputs the first 21 and second normalizing elements. The magnitude of the gain is set so that the amplitude of the endocardial component of the echo-signal eccentric signal at the output is 10-12 V, which is controlled by the control unit 15.

With such amplification, the epicardial component of the echo signal and the echo signals reflected from the pericardium and the surface layers of the lung tissue are limited. The SESLZ echo signal, amplified and filtered by the first normalizing element 21, is fed to the input of the first comparator 23, to the second input of which the reference voltage is applied. The response threshold of the first comparator 23 is set at 0.8 amplitude of the endocardial ecliptic echo signal component, which is controlled by the unit 15 control. At the output of the first comparator 23, a pulse occurs (Fig. 2e), the leading front of which corresponds to the position of the endocardial border of the echo signal. On the leading edge of the pulse, the first shaper 25 generates a pulse (Fig. 2h), the position of which corresponds to the endocardial border of the echo-signal eccentric signal.

The second input of the first trigger 27 receives a pulse of the synchronization generator 18, which sets it in one state. The first input of the first trigger 27 receives a pulse from the synchronizing generator 18, sets the pulse generated by the first driver 25, and converts it to the zero state. At its output, a pulse is formed (Fig. 2 / s), the duration of which is proportional to the distance from the ultrasound probe 2 to the endocardial borderline LVSP.

The echo signal from the output of the key 7 is also fed to the input of the second normalizing element 22, the gain of which is set so that the amplitude of the epicardial component of the echo signal at its output is 10-12 V. The amplified and filtered second second normalizing element 22 the echo signal ZLZH enters the first input of the second comparator 24, to the second input of which the reference voltage t / o / i2 is applied.

The trigger threshold is set at 0.8 epicardial level of the echo component. In this case, a pulse occurs at the output (Fig. 2L), the leading front of which corresponds to the position of the epicardial border of the SLWL echo signal. The front of the pulse is allocated by the second driver 26, the output of which receives

pulse (Fig. 2m). The second input of the second trigger 28 receives a chip pulse, which sets a single state of the trigger 28, and a pulse arrives at the first input (Fig. 2m), which takes it to the zero state.

Thus, the pulse duration (Fig. 2n) arising at the output of the second trigger 28 is proportional to the distance from the ultrasound probe 2 to the epicardial surface of the SLWG.

When the switch 16 is set to the “Measurement” position, a logical “1” potential arises, and at the output of the inverter 17, a logical “O” potential is generated. This

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The proposed device registers the curve of the change in the thickness of the posterior wall of the left ventricle of the heart in real time and measures the thickness of the LSGL at any time of the cardiac cycle by comparing the amplitude of the curve for varying the thickness of the LSLV at a given point of the cardiac cycle with the amplitude of the calibration signal.

Claims (2)

1. A device for measuring the thickness of the posterior wall of the left ventricle of the heart, comprising a generator connected to an ultrasound probe, the output of which The code combination is fed to the control unit - connected to the receiver, and an indicator that distinguishes the inputs of the first 9 and second 14 switches. In this case, at their outputs, there appear pulses / С and Я, arriving at the first and second inputs of the integrator 10, where time integration is performed In order to automate dynamic measurements and record the thickness of the posterior wall of the left ventricle of the heart in real time, serially connected video differences of pulses / C and I are entered into it. Time integrator, emitter follower, key, is selected taking into account the speed of the process of changing the thickness of the posterior wall of the left ventricle is 30 ms. At the output of the integrator 10, a signal is obtained (Fig. 2L) proportional to the difference in the coordinates of the pulses formed from the endocardial and epicardial borderline SLV. The amplitude of the signal P is proportional to the thickness ZLZH. An amplifier 11 serves to match the signal I with recorders of type 6L ЕК-3 or Н338-4П. Calibrator 20 serves as a signal for calibrating the signal I in thickness. The principle of operation of the calibrator 20 is based on the fact that the time interval for the propagation of an ultrasonic pulse (t) is proportional to the wall thickness (T), i.e. C, where C is the ultrasound velocity. Therefore, the measurement calibration is performed by applying to the first and second inputs of the integrator 10 pulses whose durations differ by a known time interval, i.e. corresponding to the known distance traveled by the ultrasonic pulse. When the switch 16 is set to the “Calibration” position, a logic potential “O appears at its output, which provides the logic potential“ 1 at the output of the inverter 17. This code combination enters the control inputs of the first and second switches 9 and 14. At the same time, the passage of pulses / is blocked (and I and the pulses of the calibrator 20 pass. endocardial echo release unit, first switch, integrator, amplifier and recorder, epicardial echo release unit connected 25 through the second switch to the second input of the integrator, and the input to the key output, the control unit, the switch and the inverter, the output of which is connected to the second inputs of the first and second switches, and the input to the third and, moreover, to the switch output, serially connected synchro generator, gate driver and calibrator, the first and second outputs of which are connected to the fourth inputs of the first and second switches, and the second input - to the second output of the synchronous generator and to the second inputs of the blocks endocardial and ikardialnogo echo signals, the second outputs of which are connected to first and second inputs of the control unit accordingly, the output of the second gate is connected to the second input key, a third output connected to the clock input of the generator, the input of the indicator through a video amplifier connected to the receiver output. 45 2. The device according to claim. 1, characterized in that. that the endocardial echo extraction unit and the epicardial echo selection unit contain the first and second normalizing elements, the first and second These pulses are fed to the first and 50 comparators, the first and second forming the second inputs of the integrator 10. Integrating the difference of these pulses by the integrator 10 makes it possible to obtain a calibration voltage of the SLWL thickness, the value of which (in cm) is set by the calibrator 20. 55 The first and second triggers, the second input of which is the second input of the endocardial and epicardial echo separation units, the second outputs of which are connected to the inputs of the first and second comparators, respectively. The proposed device registers the curve of the change in the thickness of the posterior wall of the left ventricle of the heart in real time and measures the thickness of the LSGL at any time of the cardiac cycle by comparing the amplitude of the curve for varying the thickness of the LSLV at a given point of the cardiac cycle with the amplitude of the calibration signal. Invention Formula 1. A device for measuring the thickness of the posterior wall of the left ventricle of the heart, comprising a generator connected to an ultrasound probe, the output of which Connected to the receiver, and an indicator, characterized in that, in order to automate dynamic measurements and record the thickness of the posterior wall of the left ventricle of the heart in real time, serially connected video amplifier, emitter follower, key, amplifier, emitter follower, key, endocardial echo release unit, first switch, integrator, amplifier and recorder, epicardial echo release unit connected through the second switch to the second input of the integrator, and the input to the key output, control unit, switch and inverter, the output of which is connected to the second inputs of the first and second switches, and the input to the third and, in addition, to the output of the switch, connected in series a synchro generator, a gate driver and a calibrator, the first and second outputs of which are connected to the fourth inputs of the first and second switches, and the second input - to the second output of the synchronous generator and to the second inputs of the blocks of the endocardial and epicard ialnogo echo signals, the second outputs of which are connected to first and second inputs of the control unit accordingly, the output of the second gate is connected to the second input key, a third output connected to the clock input of the generator, the input of the indicator through a video amplifier connected to the receiver output. 2. The device according to claim. 1, characterized in that. that the endocardial echo extraction unit and the epicardial echo selection unit contain the first and second normalizing elements, the first and second comparators, first and second form The first and second triggers, the second input of which is the second input of the endocardial and epicardial echo separation units, the second outputs of which are connected to the inputs of the first and second comparators, respectively. 90 2cfir 1 0Fig. 2