RU32381U1 - Device for diagnosing the state of biological tissue - Google Patents

Description

Device for diagnosing the state of biological tissue

The utility model relates to medicine and medical equipment, in particular to devices for measuring the electrical characteristics of biological objects, and can be used to conduct functional diagnostics of the state of healthy and diseased tissues of biological objects using comparative impedancemetry to determine the boundary of tissue damage, for example, in patients with lower gangrene limbs.

A device for measuring the electrical characteristics of a biological object is known, including a controlled generator with one output and input, at least one current and indifferent electrodes, a detector unit and a control and display system, an analog switch with two outputs and an input connected to the output of a controlled generator. The detector block is made in the form of two amplitude detectors having one digital output and analog inputs connected respectively to one of the outputs of the analog switch, and the analog outputs with at least one current electrode, the control and display system being made in the form of firmware controller with control circuits of an analog switch and with data exchange circuits with a control PC, with two digital buses, each of which is connected to one of the amplitude detectors via their digital smooth outputs, and input and output, the first of which is connected to an indifferent electrode, and the second to the input of a controlled generator. Amplitude detectors are made in the form of semiconductor diodes, and analog switches are in the form of integrated switches of CMOS technology. The controlled standard pulse generator is made with a controlled pulse shaper of a given shape with an adjustable frequency of 100 Hz - 500 kHz and an adjustable duty cycle of 0.5 - 5 and with an amplifier - output signal shaper with the ability to control the amplitude of the output signal 1 - 12 V. Using an microcontroller, the analog switch is made with two cascades of high-speed analog keys (see RF patent for the invention No. 2128942, IPC A 61B 5/05, publ. 04/20/1999).

the area of tissue damage of a biological object, since due to the lack of simultaneous measurement by several parameters, namely capacitive and ohmic resistance of the object, there is insufficient primary information for reliable conclusion when diagnosing various types of gangrene (dry, wet).

A device for regional bioimpedanceometry is known, which contains an alternating current generator, to the output of which are connected current electrodes, a series-connected switch, a detector, an analog-to-digital converter and a processing and indication unit, the output of which is connected to the control input of the switch, regional and peripheral potential electrodes are connected to signal switch inputs. The device comprises a voltage divider connected between potential regional electrodes, the output of which is connected to an additional signal input of the switch. The detector contains a series-connected low-pass filter, a selective amplifier and a rheosignal detection unit, and a series-connected high-pass filter, the input of which is connected to the input of the low-pass filter, and a high-frequency signal detection unit, and also a low-frequency signal detection unit, the input of which is connected to the low-pass filter output frequency, the input of which is the input of the detector, the outputs of the detection unit rheosignal, the detection unit low-frequency signal and the detection unit high-frequency signal are the outputs of the detector (see RF patent for the invention No. 2094013, IPC A 61B 5/05, publ. 10/27/1997).

A disadvantage of the known device is also the complexity of its design, due to the use of high and low frequency filters and several detection units. It also does not allow diagnostics to be carried out with high accuracy, since it is necessary to measure parameters at a multitude of points of parts of the object body that are remote from each other. Moreover, the determination of the location of the desired points at which it is necessary to measure the parameters is very difficult.

A device is also known for studying the functional state of a biological tissue, comprising a controlled generator, the output of which is connected to a current electrode, an indifferent electrode, a potentiometric electrode, an amplifier, and a phase detector unit connected in series, in order to increase the accuracy and reduce the time of investigation of the electrical parameter of a biological tissue into a device introduced a sweep generator connected to the input of the controlled generator, an amplitude detector, the input of which is connected to the output of the force body block

division, the inputs of which are connected to the outputs of the phase detector unit, and a two-channel indicator, the information inputs of which are connected to the corresponding outputs of the division unit and the amplitude detector, and the scan input is connected to the output of the scan generator, while the output of the controlled generator is connected to the second input of the phase detector unit ( see USSR copyright certificate for invention No. 1311707, IPC A 61B 5/05, publ. 05.23.1987).

However, the disadvantage of the known device is also its complexity due to the presence of a large number of electronic devices (blocks of phase detectors and fission, amplifier, amplitude detector), which due to noise and interference inherent in each device, increase the measurement error, which can lead to inaccurate diagnosis of the condition biological tissue. The process of processing the measurement results is additionally complicated due to the need to evaluate the graphical dependences of the total impedance module on frequency and phase angle tangent on frequency, which, unlike, for example, numerical estimation, complicates the diagnosis of the state of biological tissue.

The closest technical solution to the claimed is a device for electromagnetic resonance impedance measurement of living tissues of a biological object, containing a generator of test signals of variable frequency, a sensor device, which includes an inductor and a capacitor forming an oscillatory circuit, and a recorder, the input of which is connected to the output of the sensor devices. The variable frequency test signal generator and recorder are designed as a computer with an additional signal conditioning and processing device connected to it, the output of which is connected to the input of the sensor device, and the second input is connected to the output of the sensor device, while the signal conditioning and processing device contains an interface and a controllable voltage generator, the input of the first of which and the first output of the second are respectively the input and output of the device for generating and processing signals, digital-to-analog the first converter, synchronizer, frequency meter, analog-to-digital converter and channel switch, with the first group of outputs of the interface connected to the control inputs of the digital-analog converter, the second group of outputs with the control inputs of the synchronizer, the third group of outputs with the control inputs of the switch, the first group of inputs with a parallel output port of the frequency meter, the second group of inputs is with a parallel output port of the analog-to-digital converter, the output of the digital-to-analog converter is connected to swing voltage controlled oscillator, a first output of which is connected with

the first input of the switch, and the second output with the first input of the frequency meter, the second input of which is connected to the first output of the synchronizer, the second output of the synchronizer is connected to the first input of the analog-to-digital converter, whose second input is connected to the output of the switch, the second, third and fourth outputs of which are the corresponding inputs of the device for generating and processing signals. The sensor device contains a serially connected matching device, a measuring oscillating circuit, a buffer amplifier and a detector, the output of which is connected to the second input of the signal generating and processing device. The oscillating circuit is equipped with a measuring inductance coil, the winding of which can be placed on a dielectric frame, on a magnetodielectric core, on a flat dielectric frame or have frameless winding, and it is also possible to use a coil with a detachable winding. The oscillation circuit can be equipped with an inductor containing a loop winding and a coupling winding, placed on a dielectric frame, and fixed in an armored core made of magnetodielectric, while the terminals of the coupling winding are connected by conductors to two metal electrodes, respectively. The oscillation circuit can also be equipped with an inductor, the winding of which is placed on a dielectric frame and fixed in an armored core made of magnetodielectric, while the conclusions of the oscillator circuit capacitor are connected by conductors to two metal electrodes, and at each electrode the working surface is covered with a dielectric layer. The device can be equipped with additional temperature and pulse sensors, the output of which is connected respectively to the third and fourth inputs of the device for generating and processing signals (see RF patent for the invention No. 2182814, IPC A 61B 5/053, publ. May 27, 2002).

A disadvantage of the known device is also the complexity of its design and its bulkiness. In this case, it is necessary to fine-tune the parameters of the device for its operation, namely, the oscillatory circuit, the measuring inductance coil and other components of the device, which complicates the procedure and reduces the accuracy of diagnostics.

To diagnose a possible pathology of living tissues of a single organ by a known device, the parameters of the oscillatory circuit with these organs introduced in healthy people of different age groups are initially investigated and the boundaries of these parameters for each age group are established. This significantly increases the number of measurements and leads to an increase in diagnostic time.

Experimental data showed that in each case, gangrene of the lower extremities of any genesis requires an individual study of tissue viability and determination of the level of amputation. Therefore, the experimental data obtained by the known device for a group of healthy people can reduce the reliability of diagnosis, since they have significant fluctuations relative to the individual data of a particular patient.

The problem to which the proposed utility model is directed is to create a device for the study of biological tissue affected by gangrene, characterized by ease of implementation and providing the necessary reliability of the data for diagnosing the state of the tissue.

The technical result achieved by the implementation of the proposed utility model is to provide a more accurate determination of not visually established boundaries of tissue damage.

This object is achieved by the fact that in the known device for diagnosing the state of biological tissue containing a sensor device, a computer and a signal processing device containing an interface, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), a switch, the input of the switch being connected to the output of the sensor device, and the output of the switch is connected to the ADC input, the computer and the signal processing device are connected via an interface whose input / output port is connected to the connection bus according to the utility model, the sensor device contains at least two pairs of electrodes and at least two reference resistors, and the signal processing device is additionally equipped with a timer, the DAC outputs are connected to the inputs of the sensor device, while one of the DAC outputs is also connected to the second input of the switch, with one electrode from each pair connected directly to the DAC, and the other through the reference hist other interface outputs are connected respectively to the ADC input, the timer input and the input switch, the timer output is connected to the second input interface.

The use of two pairs of electrodes allows the combined measurement of the values of the active and reactive component of the impedances of a healthy and affected limb, which significantly reduces the time of diagnosis. The use of two electrodes for measuring the impedance on each limb allows measurements at diametrically opposite points of intersection of the horizontal plane with the surface of the limb. This allows you to get the most reliable values of the impedance of the investigated tissue, since the limb is examined over its entire thickness, and not the local area on its surface. Moreover, the use of two electrodes with a reference resistor as a sensor device makes it possible to significantly accelerate and simplify the process of measuring the biological tissue impedance values necessary for diagnosing the lesion area without reducing the measurement accuracy. The use in the proposed utility model of an automated signal processing device, its connection with the sensor device, allows for automated data acquisition and subsequent data transfer at the required time, which is provided by the timer and its communication with the ADC via the interface. This makes it possible to simplify the obtaining of initial data for further diagnostics and the measurement accuracy by obtaining the necessary and sufficient data using automated computing tools and, accordingly, to increase the accuracy of subsequent diagnostics.

In the present description of the utility model, the following terminology is used.

The horizontal plane refers to the plane that separates the lower parts of the human body from the overlying ones, while it is perpendicular to the sagittal (separating the right parts of the human body from the left) and frontal (separating the front parts of the human body from the back) planes (see Human Anatomy / Ed. M .R. Sapina, t. 1, M .: Medicine, 1987, p. 13).

A viable state is understood as a state of tissue in which there is no necrotization (see Surgical treatment of a purulent wound, access mode in the public information system of the Internet in electronic digital form http://lib.msmi.minsk.by/cgi-bin/showdoc file learn / 330205 & line 291, 06/11/2003), i.e. viability is the ability of a tissue that has been exposed to a damaging factor and is in a state of inhibition of vital activity to undergo surgical intervention, restore its normal functions and lead to wound healing.

A device for diagnosing the state of biological tissue is illustrated by the following drawings, where in FIG. 1 shows a block diagram of a device for diagnosing the state of biological tissue; in FIG. 2 shows an embodiment of a sensor device; in FIG. Figure 3 shows the time dependences of the voltages at the electrodes.

Positions in the drawings indicate the following: 1 - sensor device; 2 signal processing device; 3 - computer; 4 - interface; 5 - digital-to-analog converter (DAC); 6 - analog-to-digital Converter (ADC); 7 - switch; 8 - electrode; 9 - reference resistor; 10 - timer; 11 - biological tissue.

A device for diagnosing the state of biological tissue comprises a sensor device 1, a signal processing device 2, and a computer 3 (Fig. 1). The signal processing device 2 comprises an interface 4, a digital-to-analog converter (DAC) 5, an analog-to-digital converter (ADC) 6, a switch 7.

The output of the switch 7 is connected to the input of the ADC 6, while one of the inputs (potential) of the switch 7 is connected to the output of the sensor device 1, containing at least two pairs of electrodes 8 and at least two reference resistors 9, and the second input the (common) switch 7 is connected to one of the outputs of the (common) DAC 5. The outputs of the DAC 5 are connected to the inputs of the sensor device 1 as follows. One electrode 8 from each pair is connected directly to one of the outputs (common) of the DAC 5, and the other is connected to the second output (potential) of the DAC 5 through the reference resistor 9 (Fig. 1 and 2).

The signal processing device 2 is further provided with a timer 10 used to synchronize data collection processes in a given measurement system.

The outputs of interface 4 are connected respectively to the inputs of the DAC 5, ADC 6, switch 7, and timer 10. One of the inputs of interface 4 is connected to the output of the ADC 6, and the second to the output of timer 10.

The computer 3 and the signal processing device 2 are connected via an interface 4, the input / output port of which is connected to the internal bus of the computer 3, used to connect additional devices of the computer 3 (Fig. 1 and 2).

Computer 3 is an IBM-compatible personal computer with peripheral devices connected to it (monitor, printer, keyboard).

As a signal processing device 2, for example, a data acquisition board of the L-154 model (manufacturer L-CARD, Russia), which is a functionally complete system for collecting and outputting analog and digital data, can be used. The L-154 board contains a 12-bit digital-to-analog converter (DAC) with a maximum conversion frequency of 70 kHz, a 12-bit analog-to-digital converter (ADC), software-controlled multi-channel switch and timers. The board and computer 3 are connected using a standard connector

ISA bus located on the motherboard of computer 3 via interface 4, through which data and control signals are transmitted from computer 3 and data is transmitted from signal processing device 2 to computer 3.

A device for diagnosing the state of biological tissue works as follows.

To diagnose the state of biological tissue, one pair of electrodes 8 is superimposed on the test tissue 11 of the affected limb, and the other pair on the test tissue 11 of the healthy limb. In this case, the electrodes 8 must be located at diametrically opposite points of intersection of the horizontal plane with the surface of the limb. The pairs of electrodes 8 are equidistant relative to the starting point located on the patient’s body, for example, the navel. In the initial state, the voltage at the electrodes is absent.

At time to, computer 3 generates a 12-bit control code, which is transmitted via interface 4 to the DAC 5, which forms the analog voltage U corresponding to the digital signal, after which the analog signal is sent to sensor device 1 (Fig. 1).

Since, from a physical point of view, biological tissue 11 can be represented in the form of a resistor Roe and a capacitor C0b connected in parallel, at the time instant t, a transition process begins, associated with the charge of the conditional capacity of the biological tissue 11. In this case, the voltage Lb on the first pair of electrodes 8 begins to increase along exponential law

 Ro6 / (R3T + Ro6) 41-exp (-At / t3)),

where 1z (Sob + Spr) (Rar + Roe) is the time constant of the charge circuit; Rar is the resistance value of the reference resistor 9; Spr - parasitic capacitance of electric wires connecting the outputs of the sensor device 1 with the input of the switch 7; UUAH voltage at the output (potential) of the DAC 5 and at the input of the sensor device 1; - time from the beginning of the supply of the voltage pulse to the electrodes.

In the absence of a reference resistor 9, the charging process would occur almost instantly, which would not allow the measurement process to be performed. The value of Rgr is set in such a way that the total time of the transient process associated with the charge of the capacitance is from 0.01 to 0.1 seconds. During tnp, the voltage Lb reaches a constant value of Ro6 / (Rw + Roe) and the process of changing Ua almost ends.

computer 3 converts the voltage value into a digital 12-bit code. The conversion is performed at regular intervals (for example, 200 μs), which is necessary for subsequent digital processing of the measurement data. The time intervals are set by timer 10 and transmitted via interface 4 to the ADC 6. Digital data is transmitted through interface 4 to computer 3, where it is stored in RAM.

After tnp time, computer 3 sets the voltage value at the output of the DAC 5 to zero (), as a result of which the process of discharging biological tissue 11 begins. To ensure the necessary measurement accuracy under the influence of natural and industrial noise, as well as the presence of the polarization effect of the electrodes, the measurement procedure is repeated periodically. For this, in the time interval from tnp to 24, the capacitor is discharged by applying voltage to the input of the measuring circuit at a time. After the battery is completely discharged at time point 2 tnp, computer 3 sets a digital control code, which is transmitted via interface 4 to DAC 5, which generates an analog voltage —digital (Fig. 3).

Similarly to the previously considered case, the voltage Ua on the first pair of electrodes 8 begins to grow exponentially, which is described by the following relation

IE -UuAn Kob / (Kat + KobI1-exp (-D1D3)), where 13 (Sob + Spr) KatKob / (Kat + Kob); .

Thus, the law of voltage change in this case differs only in sign.

When stabilizing the change in Ua, the analog signal comes from the sensor device 1 through the switch 7 to the ADC 6.

In the time interval from to, similarly to the case considered above, the capacitor discharges and the process is repeated as many times as necessary to obtain the required accuracy.

The specified procedure for the formation of bipolar voltage on the sensor device 1 provides leveling effects of polarization of the electrodes 8 and components of living tissue associated with the inevitable rapid change in electrical parameters under the influence of direct current.

baked due to digital filtering of data received from the sensor device 1.

After taking the data using the computer software 3 and the standard mathematical algorithm, the values of Cob, Sob in the electrode location zone 8 are calculated, which are the active and reactive components of the impedance of the studied biological tissue 11. The calculation results can be presented in graphical and text form on the computer monitor 3 The time taken to take data and calculate measurements is approximately 10 seconds.

After the procedure for measuring tissue parameters in the area of the location of the first pair of electrodes 8, the measurement cycle is performed for another pair of electrodes 8.

In the case of the presence of two pairs of electrodes 8, after performing the measurements, the electrodes 8 must be located at other points of the limbs and similar measurements should be performed.

The obtained measurement data can be analyzed in the following ways.

As the values evaluated in diagnostics, one can use the values of the ratio of the reactive component of the impedance to the active component of the impedance (A) on the affected limb and the ratio of the reactive component of the impedance to the active component of the impedance (B) on the healthy limb. Subject to the ratio | VA | B / 5 diagnoses a viable state of the investigated tissue of the affected limb. To obtain the most complete picture of the defeat of the limb by gangrene, such studies must be carried out along the length of the limbs.

The values of the reactive component of the impedance on the affected limb and the reactive component of the impedance on the healthy limb can also be used as the values estimated during diagnosis. In this case, the proposed device measures the values of the reactive component of the impedance (C) on the affected limb and the reactive component of the impedance (D) on the healthy limb and subject to the ratio | D-C | D / 5 diagnoses the viable state of the test tissue of the affected limb. To obtain the most complete picture of the defeat of the limb by gangrene, similar measurements must also be taken along the length of the limbs.

areas that must be considered during further treatment, for example, amputation of part of the affected limb.

The use of a device for diagnosing the state of biological tissue, characterized by ease of implementation and providing the necessary reliability of diagnosis, allows you to more accurately determine not visually set boundaries of the affected gangrene of the limb. This allows you to leave the largest possible healthy part of the affected limb during amputation and, thus, increase the number of people who have retained the supporting function of the limb and are again able to walk after surgery for various types of gangrene.

USEFUL MODEL FORMULA

A device for diagnosing the state of biological tissue containing a sensor device, a computer and a signal processing device containing an interface, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), a switch, the input of the switch being connected to the output of the sensor device, and the output of the switch connected to the input of the ADC, the computer and the signal processing device are connected via an interface, the input / output port of which is connected to the bus connecting additional devices of the computer, and the output of the interface is connected to the input of the DAC, and the input is to the output of the ADC, characterized in that the sensor device contains at least two pairs of electrodes and at least two reference resistors, and the signal processing device is additionally equipped with a timer, the outputs of the DAC are connected with the inputs of the sensor device, while one of the outputs of the DAC is also connected to the second input of the switch, with one electrode of each pair connected directly to the DAC and the other through a reference resistor, the other outputs of the interface are connected respectively with ADC input, timer input and switch input, while timer output is connected to the second input of the interface.

DEVICE FOR DIAGNOSIS OF THE STATE OF BIOLOGICAL TISSUE

Claims (1)

A device for diagnosing the state of biological tissue, containing a sensor device, a computer and a signal processing device containing an interface, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), a switch, while the input of the switch is connected to the output of the sensor device, and the output of the switch is connected with the input of the ADC, the computer and the signal processing device are connected via an interface, the input / output port of which is connected to the connection bus of additional computer devices, and the interface path is connected to the input of the DAC, and the input to the output of the ADC, characterized in that the sensor device contains at least two pairs of electrodes and at least two reference resistors, and the signal processing device is additionally equipped with a timer, the outputs of the DAC are connected to the inputs of the sensor device moreover, one of the outputs of the DAC is also connected to the second input of the switch, with one electrode of each pair connected directly to the DAC, and the other through a reference resistor, the other outputs of the interface are connected respectively to ADC input, timer input and switch input, while timer output is connected to the second input of the interface.