DE202023104307U1 - Arrangement for characterizing the cerebrospinal fluid - Google Patents

Abstract

Arrangement (1) for the non-invasive characterization of the cerebrospinal fluid,
• with a sensor head (7),
◯ which has an emitter which emits terahertz radiation (T) when in use,
◯ and which has a complementary receiver, which receives reflections (R) of the terahertz radiation during use,
◯ and which is intended to lie against the skull of a patient (3) during use in such a way that terahertz radiation (T) radiates into the cerebrospinal fluid,
• and with a power supply unit (4), which can be connected to a mains voltage on the primary side and can be connected to the sensor head (7) on the secondary side to supply it with electrical energy,
• and with an electronic evaluation circuit,
◯ which calculates measurement data during use based on the radiation (T, R) emitted and received by the sensor head (7),
◯ where the evaluation circuit is designed in such a way that it automatically determines the extinction of different wavelengths based on the emitted and received radiation (T, R) and uses this to calculate the concentration of various substances in the cerebrospinal fluid,
• and with a display (8) for the visual representation of the data calculated by the evaluation circuit as results.

Description

The invention relates to an arrangement for characterizing the cerebrospinal fluid “cerebrospinal fluid”, hereinafter referred to as “cerebrospinal fluid”.

In practice, it is known to examine the CSF invasively, for example using a lumbar puncture or intraoperatively using a ventricular puncture. The examination is used to identify illnesses, especially in many neurological diseases, but it is also used after accidents to identify damage and to assess the extent of trauma. Samples of the cerebrospinal fluid are taken from the patient and then a sample is analyzed chemically in the laboratory and further samples are sent to a microbiology laboratory for germ incubation. For example, the concentrations of blood, protein, leukocytes and lactate in the cerebrospinal fluid can be determined.

Examinations of the cerebrospinal fluid carry the risk of spreading germs. If procedures are not completely aseptic, skin germs can be carried into the puncture canal during the puncture and result in a dangerous complication of meningitis or ventriculitis. Another risk of a CSF puncture is the possibility of a CSF leak, which can lead to leakage of the hard meninges. Another risk is injury to the spinal cord vessels, which can lead to an intraspinal or epidural hematoma with compression or damage to the spinal cord. Finally, the lumbar puncture also carries the risk that, depending on the experience of the examiner, the wrong height of the puncture can be chosen, which can occur, for example. B. a puncture in the higher lumbar region can result in symptoms of paralysis, sensory disorders or bladder/rectal disorders for the patient in the event of a spinal cord injury.

The invention is based on the object of specifying an arrangement for characterizing the cerebrospinal fluid, which enables an examination of the cerebrospinal fluid that is as simple and risk-free as possible for the practitioner and the patient.

This task is solved by an arrangement according to claim 1. Advantageous embodiments are described in the subclaims.

In other words, the invention proposes an arrangement that enables a non-invasive examination of the cerebrospinal fluid. The invention is based on the consideration that the risks previously associated with the examination are caused by the invasive nature of the examination, so that they can be practically excluded by means of an arrangement according to the proposal. According to the invention, the cerebrospinal fluid is examined by irradiating the cerebrospinal fluid through the skull with electromagnetic radiation in the terahertz range.

The arrangement according to the invention therefore firstly has a sensor head which, on the one hand, has an emitter or transmitter which emits the terahertz radiation, and which, on the other hand, has a receiver or receiver which receives reflections of the terahertz radiation.

To generate the radiation, the sensor head is supplied with electrical energy. The arrangement according to the invention therefore has, secondly, a power supply unit which can be connected to a mains voltage on the primary side and to the sensor head on the secondary side in order to supply it with electrical energy. In order to avoid damage to the sensor head and consistently good measurement results, the power supply is designed as a stabilized power supply with a voltage regulator in such a way that a specific output voltage is reliably maintained and constantly provided.

The voltage regulator can be physically separate from the power supply, but it can also form an integral part of the entire power supply that is inaccessible to an operator. In one embodiment, the voltage regulator can be operated by the operator and set to different voltage values, for example if the sensor head of the arrangement is replaceable and different sensor heads are operated with different voltages. The different sensor heads can each be equipped with a quick coupling system, for example an electrical plug connection, so that the arrangement can be operated with either one of several - at least two - sensor heads and a quick and easy change between the different sensor heads is possible.

The signals supplied by the receiver of the sensor head are fed to an electronic evaluation circuit, which is also part of the arrangement according to the invention. The evaluation circuit automatically determines the extinction of different wavelengths based on the emitted and received radiation and automatically calculates the concentration of various substances in the cerebrospinal fluid.

Finally, the arrangement according to the invention also has a display on which the results nits are displayed visually. The results, namely the data calculated by the evaluation circuit, can, for example, be represented alphanumerically, for example in the form of percentage values or absolute values of the quantity of substances recorded by sensors and/or calculated from the sensor data. Another type of visual representation can be provided in the form of a bar chart, so that a separate bar is displayed for the different substances, which represents the percentage or absolute amount of the respective substance. A standard value of the same substance can be represented in an adjacent bar, or within the same bar a standard value of the substance in question can be displayed using different colors or gray values, so that in the case of the bar diagram mentioned, it is immediately possible to read for each substance the relationship in which the sensory detected substances relate Measured values for the standard works of the respective substance are available. Both representations mentioned can be combined with each other so that the results can be displayed on the display in both alphanumeric and diagram form. In any case, the invention provides that the results are displayed optically differently than with an imaging method.

Using the arrangement according to the invention, an examination of the cerebrospinal fluid in the cranium can be carried out by placing the sensor head on the outside of a patient's skull, emitting the terahertz radiation and receiving its reflections so that they can then be evaluated. Since this type of examination is exclusively non-invasive, the risks associated with an invasive examination are eliminated.

While the emitter emits terahertz radiation in a certain frequency range, the receiver receives reflections from the various substances contained in the liquor. The measurement method is based on spectroscopy and Lambert Beer's law. The method carried out with the arrangement according to the invention makes it possible to determine an unknown concentration based on the absorption of the emitted rays. Some of the electromagnetic radiation is absorbed by solutions such as brain water, while another part of the radiation penetrates the solution and is reflected to the sensor head.

The reflected radiation is detected by the receiver of the sensor head and can either be temporarily stored for data transmission or be transmitted directly to the evaluation circuit.

The transmission T provides information about the extent to which the radiation intensity I ₀ irradiated into the cerebrospinal fluid passes through the cerebrospinal fluid at a specific wavelength. The ratio of the radiation intensity before entering the cerebrospinal fluid (I ₀ ) and after exiting (I) is described by the equation T = I / I ₀ . The extinction E, on the other hand, describes the transmission at a specific wavelength: $$\text{E}=-\text{log}\left({\text{I/I}}_0\right).$$

wobei

Eλ

Extinktion für eine bestimmte Wellenlänge λ

I

transmittierendes Licht in W/m²

I0

einfallendes Licht in W/m²

C

Konzentration in mol/m³

d

Wellenlänge in cm, und

eλ

Extinktionskoeffizient für die bestimmte Wellenlänge λ

The propagation of electromagnetic waves with their specific characteristics such as frequency and wavelength is used to identify substances. Lambert Beer's law states that the decrease in intensity when passing through a medium can determine the absorption. The absorbance of a wavelength is defined by its intensity. This absorption can be identified using the ratio between the transmitted radiation intensity and the incident radiation intensity. This process is also known as extinction. The extinction varies depending on the concentration of the absorbing substance, the wavelength of the radiation in the material being irradiated, and the extinction coefficient. $${\text{E}}_{\mathrm{\lambda }}={\text{log}}_{10}\left({\text{I/I}}_0\right)=\text{C}*\text{d}*{\text{e}}_{\mathrm{\lambda }}$$

where

Eλ

Extinction for a certain wavelength λ

I

transmitted light in W/m ²

I0

incident light in W/m ²

C

Concentration in mol/m ³

d

Wavelength in cm, and

eλ

Extinction coefficient for the specific wavelength λ

According to the invention, the liquor is examined in the skull and using radiation in the terahertz range of the electromagnetic wave spectrum. This radiation has the property of being able to penetrate the skull and reach the cerebrospinal fluid. In order to counter the potential danger of causing damage to the tissue of the human body that could be caused by the radiation, on the one hand the radiation intensity of the emitter can be set as low as possible and on the other hand the radiation can be focused in a similar way to an optical lens , so that it penetrates the tissue over a larger area, with a correspondingly low area intensity, and so that only in CSF the radiation reaches the desired intensity in the area of its focus. In order to avoid an undesirably high radiation intensity and also to generate more reflections, which may have a positive influence on the examination accuracy, in an alternative design of the arrangement the radiation can deliberately not be bundled, but rather be emitted as a parallel or even diverging beam of rays. Depending on the design of the emitter, this can be done without a lens or by means of a diverging lens connected to the beam path.

The individual components of the arrangement according to the invention do not have to be combined in one device. For example, the power supply can have its own housing, and the sensor head can be connected to the power supply via a cable and can therefore be freely movable to a limited extent. The evaluation circuit can be arranged in the same housing as the power supply, e.g. B. as a device that can be placed on a table. In this case, the cable is used to transmit energy to the sensor head and to transmit the measurement signals from the sensor head to the evaluation circuit.

An amplifier can be arranged in the sensor head, which amplifies the measurement signals emitted by the receiver before they are forwarded wirelessly or by cable.

Depending on the space required, the evaluation circuit can be accommodated in the sensor head itself, so that electrical signals from the receiver of the sensor head can be processed with as little loss and interference as possible. In this case, the cable mentioned can serve, in addition to transmitting energy to the sensor head, for signal transmission of the data calculated by the evaluation circuit.

The display can be arranged in the same housing as the power supply, e.g. B. as a monitor in the table device already mentioned. However, it can also be designed as a separate monitor that is attached to a wall or to its own holder. The image signals can be transmitted to the display using a cable. A video circuit can be arranged within the power supply housing, which generates image signals from the data calculated by the evaluation circuit, which are transmitted to the display.

Signals can be transmitted wirelessly, e.g. B. measurement signals from the sensor head to the evaluation circuit, and / or data calculated by the evaluation circuit to the display or an upstream video circuit, and / or image data from the video circuit to the display can be transmitted wirelessly.

The terahertz radiation is directed through the emitter onto the cerebrospinal fluid, with part of the radiation being absorbed by the cerebrospinal fluid. The remaining part, which passes through the CSF, is reflected and returns through the CSF to the sensor head, is received by the receiver located in the sensor head. The individual parameters are determined and analyzed based on the absorption. The parameters are identified through the characteristic properties of the absorption bands. According to the invention, terahertz radiation in the range from 0.1 to 10 terahertz of the electromagnetic spectrum is used. The individual peaks show how strong the absorption is in this area. The assignment of the characteristic properties to these peaks can be used to determine the concentration of the substances in the cerebrospinal fluid.

In a preferred embodiment of the arrangement, it is designed such that terahertz radiation in the range of 0.3 to 3 terahertz is used. This frequency range of the so-called “fingerprint” is characterized by a unique wavelength signature, similar to a fingerprint, and allows the parameters to be identified using reference values. This fingerprint area is used to identify vibrational spectra. The measured values provided by the sensor head reflect the individual wave patterns like a fingerprint. The fingerprint area is therefore particularly suitable for the use of low radiation intensities, e.g. B. can preferably be used to ensure the greatest possible protection for the patient. The fingerprint area can be used very well to determine the concentration and to assign the individual parameters, so that, for example, by means of a non-invasive examination using the arrangement according to the invention. B. the concentrations of blood, protein, leukocytes and lactate in the cerebrospinal fluid can be determined. This approach enables precise analysis and measurement of substances contained in the CSF, thereby improving medical diagnosis and treatment. In particular before the implantation of foreign material, e.g. B. Ventriculoperitoneal or ventriculoatrial shunts, precise analysis of the CSF is of great importance.

The sensor head is not handled invasively, but is simply placed on the patient's skull from the outside. This can be done manually by a person called a “handler” or automatically by a handling robot. In one embodiment of the arrangement, the sensor head is arranged in a headband, a cap, cap or similar holder, which can be pulled onto the patient's head, the Various different types of designs are collectively and simply referred to as holders. The holder ensures that the sensor head maintains its position on the skull during the examination, without the sensor head having to be moved specifically - e.g. B. by the mentioned treating person - must be maintained.

wobei m die Steigung und b den Y-Achsenabschnitt in dem zugehörigen Graphen bezeichnet und im erfindungsgemäßen Anwendungsfall die allgemeine Variable x für die Konzentration C steht und die allgemeine Variable y für die Extinktion E_λ, so dass die Gleichung im Rahmen der vorliegenden Erfindung lautet: $${\text{E}}_{\mathrm{\lambda }}=\text{m}*\text{C}+\text{b}.$$

In order to deliver reliable results, the arrangement according to the invention is first calibrated. The calibration is based on a conventional examination of the CSF in the laboratory to determine the appropriate values. In addition, the same liquor is characterized with the arrangement according to the invention. The measurement of the absorbance for the known concentrations is of great importance for the functionality of the device. The results are then displayed in a graph in which the extinction is plotted as a function of the concentration. This involves determining the solution to the general linear equation $$\text{y}=\text{m}*\text{x}+\text{b},$$

where m denotes the slope and b the Y-axis intercept in the associated graph and in the application according to the invention the general variable x stands for the concentration C and the general variable y stands for the extinction E _λ , so that the equation in the context of the present invention is: $${\text{E}}_{\mathrm{\lambda }}=\text{m}*\text{C}+\text{b}.$$

Während der Kalibrierung erfolgt die Ermittlung der Messgrenzen. Mittels der erfindungsgemäßen Anordnung kann automatisch die Anwesenheit von Erythrozyten, Hämoglobin oder Hämatorkit im Liquor erfasst werden. Um Verfälschungen zu vermeiden, ist es wichtig, dass die Kalibrierung mit Hilfe der Laborwerte am selben Tag erfolgt, an dem die Probennahme für die Laborwerte erfolgt.The equation can be rearranged according to the concentration C: $$\text{C}=\left({\text{E}}_{\mathrm{\lambda }}-\text{b}\right)\text{/m}.$$

The measurement limits are determined during calibration. Using the arrangement according to the invention, the presence of erythrocytes, hemoglobin or hemator kit in the cerebrospinal fluid can be automatically detected. In order to avoid falsifications, it is important that the calibration using the laboratory values is carried out on the same day that the sample for the laboratory values is taken.

$${\text{C}}_{\text{ERY}}=\left({\text{E}}_{\mathrm{\lambda }\text{ERY}}-\text{Y}-\text{Achsenabschnitt}\right)\text{/Steigung}$$

$${\text{C}}_{\text{Leukozyten}}=\left({\text{E}}_{\mathrm{\lambda }\text{Leukozyten}}-\text{Y}-\text{Achsenabschnitt}\right)\text{/Steigung}$$

$${\text{C}}_{\text{Eiweiß}}=\left({\text{E}}_{\mathrm{\lambda }\text{Eiweiß}}-\text{Y}-\text{Achsenabschnitt}\right)\text{/Steigung}$$

$${\text{C}}_{\text{Laktat}}=\left({\text{E}}_{\mathrm{\lambda }\text{Laktat}}-\text{Y}-\text{Achsenabschnitt}\right)\text{/Steigung}$$

$${\text{C}}_{\text{Glukose}}=\left({\text{E}}_{\mathrm{\lambda }\text{Glukose}}-\text{Y}-\text{Achsenabschnitt}\right)\text{/Steigung}$$

By applying Lambert's law and calculating the extinction E _λ = log10 (I/I0), the concentration of the parameters can be determined: $${\text{E}}_{\mathrm{\lambda }}=\text{Extinction of the various substances}$$

$${\text{C}}_{\text{ERY}}=\left({\text{E}}_{\mathrm{\lambda }\text{ERY}}-\text{Y}-\text{Axis intercept}\right)\text{/Pitch}$$

$${\text{C}}_{\text{Leukocytes}}=\left({\text{E}}_{\mathrm{\lambda }\text{Leukocytes}}-\text{Y}-\text{Axis intercept}\right)\text{/Pitch}$$

$${\text{C}}_{\text{protein}}=\left({\text{E}}_{\mathrm{\lambda }\text{protein}}-\text{Y}-\text{Axis intercept}\right)\text{/Pitch}$$

$${\text{C}}_{\text{lactate}}=\left({\text{E}}_{\mathrm{\lambda }\text{lactate}}-\text{Y}-\text{Axis intercept}\right)\text{/Pitch}$$

$${\text{C}}_{\text{Glucose}}=\left({\text{E}}_{\mathrm{\lambda }\text{Glucose}}-\text{Y}-\text{Axis intercept}\right)\text{/Pitch}$$

$${\text{C}}_{\text{H}\ddot{\text{a}}\text{matokrit}}=9*{\text{C}}_{\text{ERY}}$$

In the case of hemoglobin and hematocrit, the values can be calculated from the sensory measurements as follows: $${\text{C}}_{\text{H}\ddot{\text{a}}\text{moglobin}}=3*{\text{C}}_{\text{ERY}}$$

$${\text{C}}_{\text{H}\ddot{\text{a}}\text{matocrit}}=9*{\text{C}}_{\text{ERY}}$$

The result of these equations serves as the basis for the development of a software program called an evaluation circuit, which is able to determine the concentration from the measured values provided by the sensor head and output this data for display on a display. In a further development, the evaluation circuit can also automatically statistically analyze this data. Using the arrangement according to the invention it is possible to also examine glucose, leukocytes, protein and lactate in the cerebrospinal fluid. To achieve this, the individual parameters are analyzed in the frequency range from 0.1 to 3 terahertz by measuring their absorption bands and incorporating their characteristic properties for calibration into the concentration formula for calculating the extinction.

Apart from the fact that painful needle pricks in the head area can be avoided for patients in neurological treatment due to the non-invasive examination method possible according to the invention, a significant advantage of this non-invasive examination is the minimization of potential complications such as bleeding, infections and scarring. Compared to invasive procedures, the non-invasive method therefore offers increased safety. In addition, patients benefit from a shortened recovery time. Furthermore, the non-invasive examination enables doctors to act more quickly, which not only leads to significant time and cost savings, but can also have a life-saving effect in acute emergency situations.

• 1 den Aufbau einer Anordnung zur Charakterisierung des Liquor cerebrospinalis in Art eines Blockschaltbildes.

The arrangement according to the invention is explained in more detail below using the purely schematic representation. This shows

• 1 the structure of an arrangement for characterizing the cerebrospinal fluid in the form of a block diagram.

1 shows a schematic block diagram of an arrangement 1 for examining the cerebrospinal fluid cerebrospinalis, whereby the CSF in the cranium 2 of a patient 3 is examined. The arrangement 1 used for this purpose has a power supply unit 4, which can be connected to a power or voltage network on the primary side by means of a power plug 5 and whose output voltage is stabilized by means of a voltage regulator 6. The transmission of electrical energy is symbolized by energy arrows E.

The stabilized output voltage is supplied from the voltage regulator 6 to a sensor head 7 of the arrangement 1, an emitter for terahertz radiation and a receiver for reflected components of the emitted terahertz radiation reaching the sensor head 7 being arranged in the sensor head 7. The terahertz radiation emitted by the sensor head 7 is symbolized by an arrow T. It penetrates the skull of patient 1 and hits the cerebrospinal fluid and substances contained in the cerebrospinal fluid. The reflected radiation that reaches the receiver of the sensor head 7 is in 1 marked with R. A distance between the sensor head 7 and the cranium 2 is shown purely as an example, but only in order to be able to arrange the terahertz and reflection arrows T and R graphically. When carrying out an examination, it is intended to place the sensor head 7 on the skull of the patient 3.

In the exemplary embodiment shown, it is provided that the measurement signals that are output by the receiver of the sensor head 7 are processed directly in the sensor head 7 in an evaluation circuit. For this purpose, a chip is arranged in the sensor head 7, on which a software program runs, which represents the evaluation circuit. Deviating from the illustrated exemplary embodiment, it can be provided that the measurement signals output by the receiver of the sensor head 7 are transmitted from the sensor head 7 to an evaluation circuit remote therefrom, either unchanged or as amplified signals by means of a signal amplifier arranged in the sensor head 7. In any case, signals symbolized by signal arrows S reach a display 8 in unchanged or processed form, where the examination results are displayed visually. Immediately before the display 8 at the latest, the signals are processed into image signals in order to enable the desired visual representation.

Components of the arrangement 1 shown separately can be combined into a single device, for example the power supply 4 and the voltage regulator 6 can be arranged in a common housing, or a table device can contain the power supply 4, the voltage regulator 6 and also the display 8.

Reference symbol:

1

arrangement

2

Cranium

3

patient

4

power adapter

5

Power plug

6

Voltage regulator

7

Sensor head

8th

Advertisement

E

electrical power

T

Terahertz radiation

R

reflected radiation

S

signal

Claims (12)

Arrangement (1) for the non-invasive characterization of the cerebrospinal fluid, • with a sensor head (7), ◯ which has an emitter which emits terahertz radiation (T) when in use, ◯ and which has a complementary receiver, which receives reflections (R) of the terahertz radiation during use, ◯ and which is intended to lie against the skull of a patient (3) during use in such a way that terahertz radiation (T) radiates into the cerebrospinal fluid, • and with a power supply unit (4), which can be connected to a mains voltage on the primary side and can be connected to the sensor head (7) on the secondary side to supply it with electrical energy, • and with an electronic evaluation circuit, ◯ which calculates measurement data during use based on the radiation (T, R) emitted and received by the sensor head (7), ◯ where the evaluation circuit is designed in such a way that it automatically determines the extinction of different wavelengths based on the emitted and received radiation (T, R) and uses this to calculate the concentration of various substances in the cerebrospinal fluid, • and with a display (8) for the visual representation of the data calculated by the evaluation circuit as results. Arrangement according to Claim 1 , characterized by a voltage regulator (6) which is connected between the power supply (4) and the sensor head (7) in such a way that the voltage for supplying electrical energy to the sensor head (7) can be adjusted. Arrangement according to Claim 1 or 2 , characterized in that the emitter is designed in such a way that it emits radiation in the range between 0.1 THz and 3 THz during use. Arrangement according to one of the preceding claims, characterized in that the data calculated by the evaluation circuit are presented as results in alphanumeric form. Arrangement according to one of the preceding claims, characterized in that the data calculated by the evaluation circuit are displayed as results in the form of a diagram. Arrangement according to one of the preceding claims, characterized in that the sensor head (7) is arranged in a holder, the holder resting against the head of a patient (3) during use and holding the sensor head (7) in a predetermined position on the head. Arrangement according to one of the preceding claims, characterized in that the arrangement has more than one sensor head (7), the sensor head (7) being interchangeable by means of a quick coupling in such a way that it can be interchanged with another sensor head (7) and the Arrangement can optionally be operated with one of the several different sensor heads (7). Arrangement according to the Claims 2 and 7 , characterized in that the voltage regulator (6) can be adjusted to different output voltages. Arrangement according to one of the preceding claims, characterized in that the evaluation circuit is designed in such a way that the extinction for a specific wavelength is automatically calculated as follows: $${\text{E}}_{\mathrm{\lambda }}={\text{log}}_{10}\left({\text{I/I}}_0\right)=\text{C}*\text{d}*{\text{e}}_{\mathrm{\lambda }}$$

where E _λ extinction for a certain wavelength λ I transmitted light in W/m ² I ₀ incident light in W/m ² c concentration in mol/m ³ d wavelength in cm, and e _λ extinction coefficient for the wavelength λ. Arrangement according to one of the preceding claims, characterized in that the evaluation circuit is designed in such a way that the concentration for a specific substance contained in the liquor is automatically calculated as follows: $$\text{C}=\left({\text{E}}_{\mathrm{\lambda }}-\text{b}\right)\text{/m}.$$

where E _λ extinction for a certain wavelength λ C concentration of the substance in mol/m ³ b Y-intercept m slope Use of an arrangement (1), which is designed according to one of the preceding claims, for the non-invasive characterization of the cerebrospinal fluid. Use after Claim 11 to characterize the liquor located in the cranium (2).

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