EP1492447A1 - Method and system for optically measuring swelling of the nose - Google Patents

Abstract

The invention relates to the field of the construction of device and relates more particularly to a method and a system which can for example be used to measure a nasal obstruction. The aim of the invention is to provide a method and a system which allows to measure the swelling of the nose. This aim is attained by a system that comprises a basic device (12) with light-producing components (13) and light-detecting components (14) and emitter and receiver elements (2, 3) that are disposed outside said basic device (12) on an application element (1). The aim is furthermore attained by a method according to which light is emitted from an optical emitter element (2). An optical receiver element (3) captures the light emerging in the area of emergence of the light from the side of the nose and records the incoming values and calculates therefrom diagnostically utilizable parameters.

Description

Method and arrangement for the optical measurement of swelling conditions of the nose

Field of application of the invention

The invention relates to the fields of medicine and device construction and relates to a method and an arrangement for the optical measurement of swelling of the nose, which can be used, for example, to measure nasal obstruction after allergen provocation.

State of the art

From a medical point of view, there is a need for objectification of the measurement of the swelling state and the swelling course z. B. in allergic reactions, which are caused for example in the nasal provocation test.

Nowadays, allergic rhinitis is diagnosed by taking a symptom score (sneezing, secretion, remote symptoms such as tears in the eyes) and by measuring nasal obstruction after allergen challenge using rhinomanometry (Clement et al .: "Rhinomanometry - a review", ORL J. Otorhinolaryngol. Relat. Spec. 46, 173-91, 1984). The disadvantage of rhinomanometry here is that the measurement cannot be carried out during allergen application. With severe nasal obstruction, rhinomanometry is perceived by the patient as very unpleasant. Incorrect measurements in uncooperative patients occur frequently.

A further possibility for determining the swelling state of the nose and in particular of the nasal mucosa is acoustic rhinometry (Fisher: "Acoustic rhinometry", Clin. Otolaryngol. 22, 307-17, 1997). These measurements have a relatively wide range of results. Adequate Accuracy is only achieved for the front sections of the nose, and none can during the measurement Medication or allergen provocation take place. A continuous measurement is not possible with this method either.

Furthermore, with both methods it is not possible to say whether a nasal swelling is due to a change in the microcirculation or an edema formation.

Presentation of the invention

The object of the invention is to provide a method and an arrangement for the optical measurement of swelling conditions of the nose, with which a largely objective measurement of swelling conditions of the nose is made possible, in particular during the performance of provocation tests.

The object is achieved by the invention mentioned in the claims. Advantageous refinements are the subject of dependent claims.

The arrangement according to the invention for the optical measurement of swelling states of the nose consists of a basic device with light generating components and light detection components as well as associated transmitter electronics and receiver electronics and controllers. Furthermore, at least one optical connection is realized between the basic device and an optical transmission element, the transmission of the light generated by the light generating components into the optical connection to the transmission element being implemented by optical elements. Furthermore, there is at least one optical connection between an optical receiving element and the light detection components. Outside the basic device there are transmitting and receiving elements, which are arranged on an application part. The application part realizes an arrangement of the transmitting and receiving elements that enables the light emitted by the transmitting elements to pass through the swellable tissue of at least one side of the nose to the receiving element. Furthermore, the application part can be positively applied to at least the upper part of the nose.

With the arrangement according to the invention, the swelling of the nasal tissue is detected optically. The nasal tissue is covered from the outside with a Irradiated light source, which is emitted by a transmitting element and by a detector, a receiving element, the scattered light passing through the tissue is detected either on the same or on the opposite side of the nose. As it passes through the nasal tissue, the light passes through a number of layers of tissue such as the skin, muscles, mucous membrane, bones, cartilage and the airways. Part of the permeated tissue is characterized by swelling ability, in particular the nasal mucosa lying above the bones of the nasal turbinates. In this part of the tissue, there is an increase in blood volume during the swelling due to the inflow of blood into the erectile tissue. The inflowing blood is primarily arterial in nature and therefore normally at least 95% saturated with oxygen. Furthermore, in the event of edema possibly associated with the swelling, there is an increase in the volume of tissue water. It is therefore advantageous to carry out the irradiation spectrometrically in order to be able to measure the volume fractions of the oxygenated and deoxygenated hemoglobin and of the tissue water separately and quantitatively. This can be done either by using a white light source and a spectrometer detector (e.g. diode line spectrometer) or by using several light sources with discrete radiation spectra (LEDs, laser diodes).

Since the substances mentioned, which are involved in the swelling, have different optical absorption spectra, a separate absolute or relative determination of the volume fractions is possible using appropriate mathematical methods. Such an arrangement has not been described to date.

An advantage of the arrangement according to the invention is that it is characterized by a non-invasive application from the outside and by simple handling.

Best ways to carry out the invention

The invention is explained in more detail below on the basis of exemplary embodiments. The design of the arrangement is adapted to the purpose of the investigation. The drawings show: 1 is an appliqué part in front view (a) and top view (b)

Fig. 2 shows two variants of an application part with active transmit and

Receiving elements (a) and passive transmitting and receiving elements (b) Fig. 3 an application part and its fixation on the head and nose Fig. 4 a basic device of an arrangement according to the invention Fig. 5 is a schematic representation of the nose cross-section, showing the

Position of the optical elements and the transmission channel before and after swelling. FIG. 6 shows a schematic representation of the extinction measured values in the course of a

swelling

The arrangement according to the invention consists at least of a basic device 12 with the transmitter 15 and receiver electronics 16 required for the fulfillment of the measurement task and an application part 1 which is in direct contact with the nasal tissue during the measurement.

An application part 1 is shown in Fig. 1 a and b. It consists of a clasp-shaped body, the two sides of which can be positively attached to the nostrils. The light-emitting element, optical transmitter element 2, is arranged on one side of the application part 1, and the light-receiving element, optical receiver element 3 is arranged on the opposite side. These are either designed as discrete radiation sources and detectors, the optical axes of which are oriented in the direction of the tissue (FIG. 2a) and which are connected to the basic device 12 via current-carrying cables 4, or else as optical connections 6, 7, which transmit the light from and to the basic device 12 and which are either guided with their radiating surfaces perpendicular to the nasal tissue or are aligned with the tissue by arranging corresponding optical deflection elements 5 (mirrors, microprisms) (FIG. 2b).

According to FIG. 3, the application part 1 is fixed with the aid of a forehead carrier band 8 attached to the head. This ensures that the application part 1 is firmly positioned on the bridge of the nose during the measurement. The application part is connected to the carrier tape 8 via a bracket 10. The connection is designed so that an exact positioning of the application part on the bridge of the nose, e.g. B. by a lockable ball joint 9 or a flexible metal hose is possible. Further relevant variants of the arrangement according to the invention can be designed as follows:

- The appliqué part is adhesively attached to the nose; the appliqué part is pressed directly onto the nose using an elastic band or the circumference can be adjusted to the size of the head; the appliqué part is designed as a frame similar to glasses, which sits on the root of the nose and in which the optical transmission and reception elements are pressed against the tissue of the nose by gravity;

- An arrangement in which the transmitting and receiving elements are arranged on two separate basic elements (pads), which are adhesively attached separately on each side of the nose.

For an accurate and reproducible measurement, in addition to the spatially stable and movement-free fixing of the application part on the nose, the suppression and / or calibration of extraneous light influences is also important. It is therefore advantageous to use optical filters or to cover the measurement site during the measurement with an opaque cap, which, for. B. can be fixed as a plastic cap with on the carrier tape and if necessary during the examination is folded over the measuring field.

4 shows a basic device 12 with device-internal light generation components 13 and light detection components 14, to which a previously described application part 1 can be connected via the optical connections 6, 7. The basic device 12 consists of transmitter electronics 15 for the optical light generating components 13, receiver electronics 16 and a controller 17, to which further devices can be connected via a data interface. The transmitter electronics 15 has at its output a plurality of light generating components 13, the light of which is bundled by an optical element 18. The bundled light is introduced into an optical connection 6. A light detection component 14, into which light from the optical connection 7 is incident, is connected to the input of the receiver electronics 16.

A spectrometric measurement is advantageous for the optical measurement of swelling conditions and the differentiation of swelling causes. Light sources with a limited spectrum (LEDs, semiconductor lasers) and a photodetector that is sufficiently sensitive to the selected spectral range (semiconductor photodetector, photomultiplier) can be used for this. Alternatively, a white light source and a spectrometrically resolving detector can be used. The aim of the measurement is the acquisition of light attenuation values (optical density of the tissue) at individual wavelengths of interest over time. This results from the relationship

where ls (λ, t) denote the light intensity emitted at the transmitting element and lü (λ, t) denote the light intensity arriving at the receiving element at the wavelength λ and at time t. The extinction E (λ, t) is generally a function of light scattering and light absorption in tissue and thus provides a measurement for the geometric and optical change in the tissue. By forming the difference E (λι, t) -E (λ ₂ , t) at two wavelengths, a relative measure of the change can be determined, which reflects the ratio of the volume change values of individual tissue constituents and is largely free of geometric effects. For example, when using a hemoglobin-sensitive wavelength of λι = 800nm and an H ₂ O-sensitive wavelength of λ ₂ = 970nm, the relationship between blood and tissue water gain can be represented. Furthermore, by using special optical measurement techniques, it is possible to determine the scattering and absorption properties of the tissue separately. This requires photon transit time measurements using a high-frequency modulation technique (intensity modulation of the light source (s) and amplitude and phase measurement of the receiver signal) or a pulse laser technique (application of short laser pulses and time-resolved measurement of the receiver signal). These measurement methods as well as the associated mathematical methods for determining optical parameters such measurement data are state of the art in science and technology (e.g. Sevick et al .: "Quantitation of time and frequency resolved optical spectra for the determination of tissue oxygenation", Anal. Biochem. 195, 330-51, 1991; Patterson et al., "Time resolved reflectance and transmittance for the non-invasive measurement of tissue optical properties", Appl. Opt, 28, 2331-36, 1989).

The course of a measurement is to be explained here using the example of a provoked allergic reaction (provocation test).

After preparation of the person to be examined, the application part is fixed on the bridge of the nose near the root of the nose so that the optical transmission and reception elements on the tissue face each other and the optical radiation penetrates as much swellable tissue as possible inside the nose (Fig. 5). Then a photometric signal that is as optimal as possible is set with the aid of manual, automatic or semi-automatic adjustment of source intensity (s) and / or detector sensitivity in a range suitable for the measurement by means of optomechanical, electronic and / or software technology options. The data acquisition is then started manually by the operator. Controlled by the controller 17 internal to the basic unit, there is a repeated sequential switching of the radiation sources by the transmitter electronics 15 and, at the same time, the detection of the detector measured values by the receiver electronics 16. By separate measurement of the ambient light (dark signal) when the light sources are switched off, or alternatively by a measurement of the AC portion of a sufficient Highly modulated light signal from the light sources ensures that only the light generated by the light sources and not the ambient light that may be incident on the measuring device is measured.

FIG. 6 schematically shows absorbance measurements in the course of a swelling. The spectral light attenuation values in the unprovoked state represent the baseline of the measurement. If this is recorded in a time window of 1 to 2 minutes, an allergenic substance is administered by atomization into one or both nasal cavities and the time of measurement, e.g. B. recorded by pressing a foot switch at the time of administration tp. With an allergic reaction, swelling of the nasal tissue then begins, which causes a demonstrable increase in the spectral absorbance. 6 shows spectral extinction values, which were standardized at the start time tp for better comprehensibility. At the time tε, the swelling reaches a steady state at which no further swelling can be detected. The swelling subsides only after a time t »t _E -tp. Information that can be used diagnostically can be derived from the time course of the spectral extinction values. These include in particular:

the increase ΔE (λ) = E (λ, t _E ) -E (λ, t _P ) of the absorbance for a wavelength as a measure of the intensity of the swelling; the extinction value difference ΔE (λι) - ΔE (λ ₂ ) at different wavelengths as a measure of the increase in the volume fractions of different tissue constituents relative to one another; the time difference the reaction from the time of provocation to the final stationary state as a measure of the swelling rate and the shape of the curves E (λ, t) as an indicator of the physiological course of the swelling.

Bezugszeichβnliste

1 - Applied part

2 - Optical remote control

3 - Optical reception element

4 - live cable

5 - optical Umlβnkθlθment - optical connection to the Sendθθlement

7 - optical connection to the receiver element

8 - browband

9 - ball joint

10 - mounting bracket

11 - transmission channel

12 - basic device

13 - Generating Components

14 - Light detection component

15 - transmitter electronics

16 - Receiver electronics

17 - controller

18 - optical element

Claims

claims 1. Arrangement for the optical measurement of swelling conditions of the nose, consisting of - a basic device (12) with light generating components (13) and light detection components (14) as well as associated transmitter electronics (15) and receiver electronics (16) and controller (17), - At least one optical connection (6) between the basic device (12) and an optical transmission element (2), the transmission of the light generated by the light generating components (13) into the optical connection (6) to the transmission element (2) by optical elements ( 18), at least one optical connection (7) between an optical receiving element (3) and the light detection components (14), transmitting and receiving elements (2, 3) which can be arranged outside the basic device (12) and which are on an application part (1) are arranged, the application part realizing an arrangement of the transmitting and receiving elements (2, 3) which enables the light emitted by the transmitting elements (2) to pass through the swellable tissue of at least one nose side to the receiving element (3), an application part (1) which can be positively placed on at least the upper part of the nose, 2. Arrangement according to claim 1, in which one or more light sources with different emission wavelengths are used as light generating components (13). 3. Arrangement according to claim 2, wherein the light generating components (13) are an LED and / or a laser and / or a halogen lamp. 4. Arrangement according to claim 1, wherein the transmitter electronics (15) realizes a constant optical power of the light generating components (13). 5. Arrangement according to claim 1, wherein the transmitter electronics (15) realizes an intensity modulation of the light generating components (13). 6. Arrangement according to claim 6, wherein the transmitter electronics (15) realizes a high-frequency modulation of the light generating components (13). 7. Arrangement according to claim 1, wherein the transmitter electronics (15) realizes light pulses of <1 ns duration. 8. Arrangement according to claim 1, in which one or more photodetectors and / or spectrometer detectors are used as light detection components (14). 9. The arrangement according to claim 8, wherein the light detection components (14) are photo semiconductor detectors and / or photomultiples. 10. The arrangement according to claim 1, wherein the application part (1) consists of a clasp-shaped rigid to slightly flexible base body or two separate units. 11. Arrangement according to claim 1, in which the positive connection of the application part (1) with the nose is realized adhesively or via a stretchable / length-adjustable holding strap (8) running around the back of the head or via a frame similar to glasses. 12. The arrangement according to claim 11, in which an adjustable mechanical connection (9, 10) is realized between the holding band (8) and the application part (1) for stable fixing of the positive connection. 13. Arrangement according to claim 1, in which optical shielding elements (8, 9, 10) are realized around the measuring field. 14. Arrangement according to claim 13, wherein the shielding elements (8,9,10) are an opaque cap or optical filter. 15. The arrangement according to claim 1, in which at least two optical transmitting and receiving elements (2, 3) are arranged on the application part (1), each an optical transmitting and receiving element (2, 3) are arranged on each side of the nose and the application part (2). 16. A method for the optical measurement of swelling conditions of the nose using the arrangement according to at least one of claims 1 to 15, in which light from light generating components (13) via optical elements (18) and via at least one optical connection (6) to at least one optical Transmitting element (2) is directed, or the optical transmission elements (2) emit this light, the arrangement of the optical transmission element (s) (2) on the application part (1) permitting the passage of the light through at least one side of the nose and in the area of the exit of the light from the at least one nose side, at least one optical receiving element (3) receives the emerging light and is guided via optical connections (7) to the light detection components (14) and the incoming values, which represent the temporal course of the spectral extinction caused by the Light generating components (13) generated optical radiation at selected Emissi Show wavelengths before and during a natural or provoked swelling of the swellable nasal tissue, record them and use them to calculate diagnostically usable parameters. 17. The method according to claim 16, in which different light-generating components (13) with different emission wavelengths are used for the realization of a measurement, which are successively switched on by the transmitter electronics (15). 18. The method as claimed in claim 16, in which a dark value is measured in the case of non-activated light-generating components (13) before the measurement is carried out, in order to correct the environmental influences. 19. The method according to claim 16, in which during the implementation of a measurement at the same time as the detection of the light that has passed through at least one nose side, an intensity measurement of the light generating components (13) is carried out to detect the optical output power. 20. The method according to claim 16, in which light from a single white light source (13) is emitted to differentiate different tissue components and the reception of the light after passage through at least one nose side is realized by a spectrometer detector (14). 21. The method according to claim 16, wherein the light generating components (13) emit light with different carrier frequencies in an intensity-modulated manner and the received light signals are detected separately by a frequency demultiplexing method. 22. The method according to claim 21, wherein the intensity modulation is implemented sinusoidally. 23. The method according to claim 16, wherein the light generating components (13) emit high-frequency modulated light and the phase shift and amplitude attenuation is determined for the received light signals by demodulation. 24. The method according to claim 16, in which the light generating components (13) emit very short light pulses of <1 ns and the temporal photon arrival distribution is determined from the received light signals via a time-resolved optical receiving element (3). 25. The method of claim 16, wherein the measurement of the swelling of the nose is carried out and recorded separately for each nasal cavity / side of the nose. 26. The method according to claim 16, that light of different wavelengths is guided by the light generating components (13) to at least one optical transmission element (2) on each side of the nose and is received by the optical reception elements (3). 27. The method according to claim 25, wherein light of different wavelengths is emitted from at least one light generating component (13) at least one transmitting element (2) is routed in succession on each side of the nose.