WO2013013782A2

WO2013013782A2 - Method and device for monitoring the filling level of the bladder of a patient

Info

Publication number: WO2013013782A2
Application number: PCT/EP2012/002958
Authority: WO
Inventors: Axel Cordes; Marian Walter; Steffen Leonhardt; Harry Wolfgang Plewa; Klaus MöHRING; Rüdiger RUPP; Robert Pikkemaat
Original assignee: Rheinisch-Westfälische Technische Hochschule Aachen (RWTH); Universitätsklinikum Heidelberg
Priority date: 2011-07-22
Filing date: 2012-07-13
Publication date: 2013-01-31
Also published as: WO2013013782A3; DE102011108252A1

Abstract

The invention relates to a device and a method for monitoring the filling level of the bladder of a patient, in which method several electrodes (4), in particular more than four electrodes (4), are arranged on the body surface of a patient (1), around the bladder of the patient (1), and an alternating current flowing through the body is fed in through at least one pair of two electrodes (4), wherein a respective alternating voltage measurement value is detected on several electrodes (4), and wherein the alternating voltage measurement value itself, or at least a result value calculated therefrom, forms a measure of the filling level of the bladder, in particular wherein an alarm signal is generated after said measurement is compared with at least one comparison value.

Description

Method and device for monitoring the urinary bladder level of a patient

The invention relates to a method as well as a device for monitoring the urinary bladder level of a patient. In this context, the term "patient" can be understood as meaning both a patient in the field of human medicine and veterinary medicine.

In the prior art, it is known that patients with neurological damage, for example, in the case of paraplegia or multiple sclerosis or people with limited consciousness, a timely emptying of the

Can not control the bladder because these patients are not able to feel the urinary bladder filling by restricting the sensory perception.

In such patients, the ability of the muscular control of bladder emptying is often impaired, so that a regular

Catheterism becomes necessary, affecting the quality of life of the sufferer

impaired.

It is also known, the bubble level, for example, with

To check ultrasound examinations. Although there are already devices that can be operated by the patient himself, a continuous measurement is due to the necessary continuous positioning of an ultrasound head on the

CONFIRMATION COPY Abdominal wall uncomfortable. Other methods use probes that need to be inserted into the bladder. This too is unpleasant and harbors

Infection risks.

It is therefore the object of the invention to provide a method and a device by means of which the bladder level can be monitored continuously in a convenient and convenient manner for a patient, preferably at an optimum time for a necessary

To determine bladder emptying. It is also an object of the invention to allow the affected patients to gain in quality of life, although even with the method or the device, the disease itself is not treatable.

According to the invention, this object is achieved by a method for monitoring the bladder level of a patient in which a plurality, for example more than four electrodes on the body surface of a patient are arranged around the patient's bladder and through at least one pair of two electrodes a fluid flowing through the body Alternating current is generated, wherein a plurality of electrodes, a respective alternating voltage measured value is detected, wherein the alternating voltage measured values themselves or at least one result value calculated therefrom forms a measure of the bubble level. Such a formed measure can then e.g. be used to generate a warning signal after comparing the measure with at least one comparison value, e.g. to indicate to a patient that the bladder needs to be emptied.

The object is further achieved by a device for monitoring the bladder level of a patient, in particular such a device with which the aforementioned method can be performed, the one

An electrode assembly having a plurality of electrodes, for example comprising a number of more than four electrodes, which can be applied to the body surface of a patient around the bladder of the patient and having an electronic unit with an AC power source, in particular one Constant AC power source, by means of at least by a pair of two electrodes, an alternating current can be impressed and at least one

Voltage sensor, with which a plurality of electrodes, a respective AC measured value is detected, wherein the

AC readings themselves or at least one thereof, e.g. calculated by an electronic unit result value forms a measure of the bubble level, in particular wherein the electronic unit is arranged to issue a warning signal from a comparison of the measure with at least one comparison value.

The electronics unit can be used here e.g. be in one embodiment directly a part of the device according to the invention or form an external unit. The

Calculation can therefore take place both directly in the device according to the invention, as well as externally. With external calculation, the electronics unit can communicate with the device via cable or wirelessly.

The measurement of the alternating voltage measured values can be at one

selected electrode relative to a reference potential. The

Reference potential can be given by a further electrode, so that in such a case, a respective alternating voltage measured value between two electrodes is measured, that is in each case on a pair of two electrodes.

In this case, the selected electrodes of such a pair need not be adjacent, but they may be adjacent. The

AC readings may be taken at multiple pairs of electrodes, including all possible pairs of two adjacent or non-adjacent electrodes, particularly excluding the pair of electrodes through which the AC current is impressed into the patient's body in that particular case.

The aforementioned arrangement of the electrodes on the body surface is understood to mean that the electrodes are either in direct conductive contact with the body surface or at least capacitively coupled to the body surface, since in these cases there is the possibility of over selected pair of two electrodes to flow an alternating current through these selected electrodes through the body.

The entirety of the electrodes used in the method or the device may, in addition to the electrodes arranged on the body surface, also comprise at least one electrode which can be arranged inside the body of the patient, for example, through a body opening in the body Patient is introduced, eg through the penis, rectally or vaginally. It may also be intended to arrange at least one electrode on / in a catheter so that such an electrode can be introduced into the body together with the catheter, e.g. also directly into the bladder.

The mentioned measure of the bubble level, depending on the design of the

Process or the device may be a single value, or a variety of values, e.g. also a record of a variety of values. Such a data set may also be 2- or 3-dimensional, e.g. form a data field or a data space, depending on the calculation.

The essential core idea of the invention is based here on the fact that by impressing an alternating current into the human body between a pair of two electrodes from all the electrodes at other electrodes, for example in each case two other electrodes, ie those which are not current-flowed, a voltage is measurable, which is of the impedance of the body tissue in the influence of the impressed by the alternating current alternating electric field.

Thus, it can be seen that the bladder level affects the impedance in the abdominal volume. This can happen on the one hand by the urine itself or by the bubble-induced displacement of other organs or tissues. Therefore, the bubble level or the volume of the liquid-filled bladder inside the body significantly influences the impedance of the body in the area surrounding the bladder so that, depending on an alternating current flowing through the body, the voltage differences at the other electrodes change depending on the bladder level. This alternating current may have a constant or varying amplitude and / or a constant or varying frequency.

A measuring step may here be e.g. provide that alternating current of at least one predetermined frequency and / or amplitude is impressed between selected pairs of two electrodes, and for each impression between other selected pairs of two electrodes, the height of the

AC voltage detected, so measured and stored. After each such measuring step, the bubble level can from the

AC measured values can be determined, it being possible to repeat such a measuring step at intervals, in particular periodically, so as to obtain a continuous monitoring of the bubble level.

It is possible, in the simplest embodiment of the method according to the invention or even the device already in the

AC readings itself to obtain a measure of the bubble level. For example, For example, the AC measured values, at least a partial number, can be compared with comparative values, e.g. those which were previously used as a reference in the case of an emptied bladder, in particular for a patient

were recorded.

Here, for example, it may be provided for each pair of two electrodes, through which a current is impressed into the body, in a state in which the bladder of the patient is empty, several comparison values for the others

Pairings of electrodes, then to a later Time at which a filling of the bubble is reached to be able to determine the filling by comparing the measured values of both times.

In the case of a number of N electrodes, a maximum of (N x (N-3) / 2) alternating voltage measured values or comparison values can thus be detected, although it is not absolutely necessary for carrying out the method to detect the maximum number of possible values.

Likewise, it can not be provided that the alternating voltage measured values which are recorded in the case of a filled bladder or even when the bladder is empty during a reference measurement are directly themselves as measures or comparative values

but to calculate at least one result value from these alternating voltage measured values. One or more

Result values, if necessary a data set or data field can then form the measure or, when measured with an empty blister, form at least one comparison value.

As mentioned above, it can be provided in the method and the device according to the invention not only impress an alternating current between a single pair of two electrodes and then to measure the AC voltage between other electrodes, but rather the impressing of the current successively for several, eg also for a total of all possible pairings of two electrodes and in each of these steps carried out in each case between a single or several, e.g. also to measure the AC voltage between all other possible pairings of two electrodes.

In principle, each of the electrodes used for carrying out the method in a device by cables with an electronic unit

be connected, which is adapted to each energize a selected pair of two electrodes and which is further configured, with at least one voltage sensor, the AC voltage to a plurality, in particular all to detect other pairs of mutually adjacent and / or non-adjacent two electrodes.

This may for example be provided that a single

AC voltage sensor is provided to the succession to

Voltage measurement in each case a pair of electrodes is switched on or that a plurality of AC voltage sensors is provided, in particular for each possible or selected electrode pairing one to the

For example, to be able to measure alternating voltages at the same time for these pairs of electrodes.

In a preferred embodiment of the device, it may be provided that the electrode arrangement is designed as a garment that can be worn by a patient. For example, such

Garment as pants, e.g. Underpants, be formed, on the inside of the electrodes are arranged so that they either have a conductive contact to the skin surface of the patient or at least capacitively coupled to the skin surface.

For example, in the formation of a garment as trousers, the electrodes may be arranged at least partially in the area of the upper trouser waistband. In such an arrangement, these electrodes of the waistband form a group of electrodes that lie substantially in a plane perpendicular to the body's longitudinal axis, and preferably this plane intersects the patient's bladder. This ensures that there is a sufficiently strong influence on the measured AC voltages as a function of the bubble level.

Likewise, it can be provided that the electrodes are formed, for example, as a belt and in this way can simply be placed around the pelvis of a patient. The formation of an electrode assembly of the device as a portable

Garment here has the particular advantage that the monitoring of the bladder level for the patient does not require the use of a special unusual equipment, but that the monitoring can take place by wearing garments to which the patient is accustomed. So also in everyday life a e.g. continuous monitoring of the bubble level.

In a further development of the device, it can be used at a e.g. As a garment formed electrode assembly may be provided that at least a portion of all the electrodes provided in the device are arranged in the region of a respective leg, in particular the thigh of a patient on the body surface. By way of example, some of all the electrodes may be arranged in the region of the lower trouser cuffs in the case of an electrode arrangement in the form of pants, preferably underpants. Similarly, electrodes formed in the region of the buttocks and / or an electrode on the abdominal wall may also be present in an electrode arrangement designed as a trouser.

Due to the arrangement of the electrodes not only within a plane perpendicular to the body longitudinal axis, as is the case with the upper waistband or a belt, the advantageous effect is achieved that the impedance change in the interior of the body by a change in level of the bladder in more than one plane, In particular, can be checked in three dimensions and thereby obtain the measurements higher reliability.

In general, it may e.g. be provided that a plurality of the electrodes of the electrode assembly are within a plane, in particular the at

Carrying the electrode assembly cuts the bubble, with a minority of all electrodes are outside this plane. As described in the upper embodiment, the plurality of electrodes can be arranged in the upper waistband area and the minor number of lower trouser bottoms and / or buttocks and / or abdominal wall, etc. In a development, it can also be provided that at least one electrode of the electrode assembly can be inserted into the body of the patient, for example by the penis, rectally or vaginally, for which the at least one electrode may be arranged, for example, on a cable, in particular connected to the item of clothing ,

Furthermore, provision may be made for the electronic unit, in addition to the means for impressing a particularly constant alternating current of a single fixed frequency or possibly also of a plurality of frequencies, sequentially or simultaneously, and at least one alternating voltage sensor, to have a signaling unit with which a patient receives a signal

Bubble volume or the bubble level dependent signal can be displayed. Such a display may e.g. optically, acoustically or haptically (for example by vibration). A patient who has no sensation for the bladder level thus receives a signal by the device according to the invention to effect emptying of the bladder.

Here it can be provided, for example, that the electronics unit is integrated in a paraplegic patient in a wheelchair, wherein the electrode having part, such as the aforementioned garment, in particular a pair of pants, can be connected by cable or by radio to the electronics unit. A signaling unit of the type described above can also be arranged on the wheelchair, in particular in a position which is easily perceptible by a patient sitting in a wheelchair. It can also be provided, a signaling unit wired or by

Radiocommunication such that it can be worn on an arm, especially the forearm and here preferably in the wrist area of a patient, comparable to a clock.

For carrying out the method, the device can furthermore be set up in such a way that from the alternating voltage measured values of each measuring step a two-dimensional or three-dimensional, at least latent, one In this case, in one possible embodiment, the impedance values or impedance change values of the representation may form the result values mentioned at the outset, in particular thus a data field or a data space.

In this case, a measuring step may preferably be a method step in which an alternating current is impressed successively on a plurality of selected or predetermined electrode pairs, in particular on each possible electrode pair, and on several others, in particular all others, for each pair of electrodes on which such an alternating current is impressed Electrode pairs of two electrodes, in which no alternating current is impressed, the

AC voltage is detected by measurement.

Depending on the arrangement of the electrodes around the bladder of a patient, such a method for detecting the alternating voltage measured values can then be followed by a two-dimensional or optionally also three-dimensional, at least latent tomographic representation of the impedance or

Impedance change of the body region to be calculated by the

Surrounding electrodes is what can be used in the state of the art basically known methods of electrical impedance tomography (EIT).

By means of such calculation methods, for example, two-dimensional tomographic representations can be calculated which determine the impedance or, depending on the method, the impedance change in a section transversely, in particular perpendicular to the body axis. Such a two-dimensional

Tomographic representation can be created, for example, when the electrodes of the aforementioned electrode assembly are substantially all located in a plane that is transverse, in particular perpendicular to the body longitudinal axis and preferably the bladder intersects. In the case of a distributed arrangement of the electrodes also outside such a plane, there is also the possibility of a three-dimensional, at least latent tomographic representation of the impedance or

To calculate impedance change.

Such calculations are not the subject of the here described

Are known to those skilled in the art, for example as a classical back projection algorithm or as a modified Newton-Raphson algorithm, as e.g. in the publication by Lionhart et al., 2005 Part 1: Reconstruction Problem, in: David Holder (EDS). Electrical impedance tomography: methods, history and application. Series in medical physics and biomedical engineering Bristol: Institute of physics Publishing 1 - 64 is described.

The methods described here and, if appropriate, other algorithms which can also be used here within the scope of this invention for determining a two-dimensional or three-dimensional tomographic representation accordingly form the impedance or impedance change distribution in FIG

Electrode arrangement certain sectional area or by the

Electrode assembly included volume / space.

In the context of the invention, the impedance values or

Impedanzänderungswerte the respective representation, the result values, which result from calculation of the AC measured values. Such a tomographic representation can itself be a measure of the

Form bubble level or it can be obtained from the tomographic representation information by calculation / evaluation / image processing, which then form the measure.

For example, there is the possibility of a computed tomographic

Compare representation at a given time with such a representation that was taken with a blank bladder as a reference in the same patient with the same device. For the purposes of the invention, an at least latent tomographic representation is understood to mean that the impedance or

Impedance change distribution in the section plane determined by the electrode arrangement or the volume spanned by the electrodes is not necessarily essential for carrying out the method according to the invention, e.g. must be represented by a display device, but at least the calculated result values of the impedance distribution or

Impedanzänderungsverteilung present for the implementation of the method in the device according to the invention or an external data processing system / electronic unit.

Since in the case of electrical impedance tomography the determination of exact absolute impedance variables requires very complex calculation methods, it can be provided in the case of the invention described here to determine the impedances on the basis of original values of the alternating voltages when the bladder is empty. For this purpose, it may be provided to detect alternating voltage measured values, as described above, in an emptied bladder of a patient in at least one measuring step or, if necessary, to record them repeatedly in several measuring steps and in each case in order to then apply impedances as a so-called functional electrical impedance tomography to calculate.

In such a case, a tomographic representation of two-dimensional or three-dimensional nature does not represent an exact value of the impedance, but sufficiently meaningful relative values.

Moreover, in an extension, it may also be provided to form a functional analysis of at least one tomographic representation with respect to changes (the impedance or impedance change values) over time, eg to form a tomographic differential representation Subtraction of two tomographic representations created at different times.

In such a case, the temporal evolution of the bladder filling in tomographic representations can be detected, with static impedances no contribution or only a noise contribution in the tomographic

Form differential representation. Thus, this type of representation shows only the impedance change between the two fixed times at which the two tomographic representations subtracted from each other were created.

It can thus also be provided in a possible embodiment when carrying out the method according to the invention, continuously, e.g. periodically such functional analyzes, e.g. Calculate difference representations from the current and the previous tomographic representation or several previous representations. Such an analysis, in particular

Difference representation may in turn be e.g. considered by itself to be a measure of the bubble level. Again, the measure can again represent a data field or even a data space.

In this embodiment, in turn, there is the possibility of the individual

Result values that a tomographic analysis in particular a

Make difference representation, compare with stored

Comparison values, e.g. a tomographic representation of the empty state of the bubble in order to form a warning signal. For this purpose, it may be provided that a tomographic representation of a deflated bladder as a

Comparison representation or a plurality of comparative values in the

Device stored to keep.

In yet another possible embodiment of the method or the device of the device, it is possible, at least part of the result values of a tomographic representation or even a sum summation, wherein the sum thus formed forms a new result value in the context of the invention, in particular in this case a single numerical value as a measure of the bubble level.

In one possible embodiment, only one such part of

Result values of a tomographic representation for summation

be used in the tomographic representation surface or spatially through a defined environment, e.g. predefined environment is bounded around the bladder. So can summation contributions from others

Body areas, such as pelvic bones, etc. are hidden.

It is also possible, basically all result values of a

To summarize tomographic representation and thus to form a new result value in the context of the invention. Such a result value forms only a single numerical value as a measure, which is therefore to be compared according to the invention only with a single comparative numerical value in order to output a warning signal. In the same way, a comparative number value can be determined with emptied bladder.

In one embodiment, it may be provided that, in the case of a tomographic differential representation, in which body regions unchanged with respect to impedance form no contribution or only a noise contribution between two measurement instants, as the bubble filling progresses, an annular region in the tomographic two-dimensional or

Three-dimensional difference representation is taken by the moving outward in the filling bladder wall. With progressing

Bubble level can thus change the sum of this result due to the change from the environment, as the unmodified

Impedance regions of body tissue surrounding the bladder do not make an effective contribution to the sum. In another possible embodiment, in which a representation of a functional electrical impedance tomography is used as the basis, it may be arranged that in the region of the bladder the impedance does not change annularly but flatly with respect to the surrounding tissue, so that the aforementioned sum and the hereby formed Result value with

As the bubble level progresses, so does a change because the sum of the contributing impedance values in the area of the bubble changes with respect to the environment

Accordingly, in such a case it may be e.g. a comparison of the result value for falling short of or exceeding a e.g. stored comparison value are then made to then a corresponding signal on the

Bubble level to generate.

It may also be in another embodiment also e.g. by means of a

Image processing software in the latent tomographic representation of the size or the volume of the bubble are determined. For example, can the here

Bubble edges are detected by the gradient of the impedance, which increases in the amount of bubbles at the edge of the bubble. After determining the edges, this information can be used to calculate the volume or, on average, the area occupied by the bubble in the representation. Also, this value for volume or area can be a measure of the bubble level in the sense of the invention and e.g. for comparison with a saved

Comparison value are used to generate a warning signal.

In a preferred embodiment, it may be provided that the

Device, in particular the electronic unit of the device is arranged to generate a function of the determined measure a signal for emptying, with which a valve is controlled, which ensures an automatic emptying of the bladder. Such a valve may for example be arranged on a catheter which is applied through the urethra, in particular directly into the bladder of the patient. The said signal can thus be used instead of or in addition to a warning signal be generated. In such a case, for example, the valve can electrically via the catheter, for example via a recorded by catheter line with the

Device, in particular the electronic unit to be connected.

Embodiments of the invention will be described below.

FIG. 1 shows the application of the method or the device to a human patient 1 who uses a device according to the invention which comprises an electrode arrangement 2 and an electronic unit 3. The electrode unit 2 is embodied here as a pair of underpants, wherein a plurality of electrodes 4 are arranged in the area of the upper waistband, for example on the inside of the trouser waistband, which supports the body of the patient 1 in FIG

Surrounded pool area and thus lie in a plane which intersects the bladder.

In this embodiment, the electronic unit 3 is connected to the electrodes 4 of the electrode assembly 2 via cable 5, wherein for each electrode 4, a corresponding cable 5 is provided. The electronics unit may form an integral part of the device according to the invention, and e.g. in the garment, here the pants are arranged. The electronics unit can also be replaced by a e.g. be designed external data processing system (PC), with the external evaluation is made.

It is therefore possible, by means of the electronic unit 3,

for example, a digital signal processor 6 present therein, via a digital / analog converter 7 between a selected pair of two

Electrodes 4 from all electrodes have a predetermined e.g. constant

To impress alternating current, which flows between these electrodes 4 through the body of the patient 1 and then for this pair of two electrodes on other, preferably all other pairs of electrodes existing

Measuring voltage by means of an analog / digital converter 8, for example, to detect the same unit 3. For a measuring step of such a detection of an alternating current is impressed at several, for example at each possible electrode pair of two electrodes 4 and then measured for each of these pairs at several, for example all other electrode pairs of adjacent electrodes, the AC voltage.

This results in a large number of measured values, which are as described at the outset

has been described general part, with an algorithm according to the

known methods of particular functional electrical

Impedance tomography (fEIT) in a two-dimensional, at least latent

tomographic representation can be converted, which shows for example the figure 2.

This figure 2 visualizes at a predetermined resolution in a sectional plane perpendicular through the body longitudinal axis, i. Here, the plane that is essentially defined by the electrode assembly 2, the impedance or

Impedance change of the body region in this cutting plane based on an original reference measurement.

Here it is visualized that in this graphic representation the region 9 has a different impedance from the surrounding region 10, which here is due to increased bubble filling. In the graph of Figure 2, the border of region 9 substantially represents the outer contour of the filled bladder with an impedance changed from the environment. As the change in impedance fails concretely in the application of the method, e.g. Depending on whether the AC had a constant or varying frequency and / or constant or varying amplitude in the measurement. The evaluation is in this respect to the measurement phase

adapt.

With a summation of all impedance values in the quadratic field of FIG. 2 shown here, a modified one thus results Sum signal compared to an original, but not here

illustrated graphical representation in an empty bladder, since in the figure 2 shown here in the area of the bladder, which through the area 9

is represented, the impedance is changed in a large area.

The sum value of all, at least part of the impedance values of such a preferably functional electrical impedance tomography therefore represents an adequate measure to determine the bubble level, in particular if there is a comparison value of this sum value, which was determined with a deflated bubble.

For example, it is possible with a device of

According to the invention perform a comparison measurement with the specific patient who later the device or at least the

Electrode assembly of this device worn on the body to obtain meaningful results.

For example, Figure 3 shows the decrease in so-called global impedance, i. of the above-described summation value with increasing

Bladder volume obtained by measurements in which the bladder was artificially filled by infusion to demonstrate the functional principle of the invention.

It can be seen here that the summation values show an essentially linear decreasing behavior as a function of the bubble filling, so that it can be concluded that if the sum value has a certain value

Comparison value is reached, such a bubble level is reached at which a bladder emptying should be performed. Such a case can then be signaled. For this purpose, the display unit can be controlled by the electronic unit to generate a corresponding signal and bring the patient to the display.

FIG. 4 shows a further embodiment of at least the electrode arrangement of the device according to the invention, which differs from that of FIG. 2 in that here not only electrodes 4 in the region of the upper one

Hosenbundes are arranged, but also electrodes 4a in the pant legs, in particular the respective lower bundles.

Likewise, it may be provided that electrodes are additionally arranged in the buttock region here on the back of the pants, which is not shown. This results in an arrangement with respect to Figure 1, in which the electrodes surround the bladder of the patient not only in a plane, but also outside this plane, in particular three-dimensionally arranged around the bladder.

This opens up the possibility of calculating a distribution of the impedance or impedance change with the method or device according to the invention not only two-dimensionally, but even three-dimensionally. In such a case, the sum of the individual values that make up the three-dimensional tomographic representation can be formed in the same way, irrespective of whether they are impedance values or

Impedance differences between two three-dimensional tomographic

Representations act.

By describing the invention, it will be apparent that the method and apparatus assist patients in performing bladder emptying that themselves can not develop a bladder fill level sensation. The

Invention thus helps to significantly increase the quality of life of such patients.

Claims

claims

A method of monitoring the bladder level of a patient,

characterized in that a plurality, in particular more than four electrodes (4) are arranged on the body surface of a patient (1) around the bladder of the patient (1) and through at least one pair of two electrodes (4) an alternating current flowing through the body is fed, wherein a plurality of electrodes (4)

AC measured value is detected, the

AC voltage readings themselves or at least one of them

calculated result value forms a measure of the bubble level,

in particular, after a comparison of the measure with at least one comparison value, a warning signal is generated.

2. The method according to claim 1, characterized in that from the

AC readings a two-dimensional or

three-dimensional at least latent tomographic representation of the impedance or impedance change of a bladder

Body area is calculated, the impedance values or

Impedance change values of the representation forming the result values.

3. The method according to claim 2, characterized in that a

functional analysis of at least one tomographic representation with respect to changes over time is formed, in particular a tomographic difference representation is formed, which results from subtracting two at different times created tomographic representations.

4. The method according to any one of the preceding claims, characterized

characterized in that at least part of the result values of a tomographic representation or of a tomographic difference Representation is summed and forms a new result value, in particular wherein a comparison value is formed by forming the sum of the same proportion of result values, which were determined for each user individually with empty bladder.

5. The method according to any one of the preceding claims, characterized

characterized in that when exceeding or falling below the particular intraindividuelle comparison value, a signal is generated that indicates a user of the method, the need for bladder emptying.

6. The method according to any one of the preceding claims, characterized

in that at least one electrode is introduced into the body of a patient (1).

7. Device for monitoring the bladder level of a patient,

in particular with a method according to one of the preceding claims, characterized in that it comprises an electrode arrangement (2) with a plurality of electrodes (4), in particular with a number of more than four electrodes (4), which on the body surface of a patient (1 ) can be applied around the bladder of the patient (1) and one

Electronic unit (3), with an AC power source, in particular AC constant current source, by means of at least one pair of two electrodes (4) an alternating current can be generated and at least one voltage sensor with which a plurality of electrodes (4) a respective alternating voltage measured value can be detected the

AC voltage values themselves or at least one result value calculated therefrom by the electronic unit (3) is a measure of the

Bubble level forms, in particular wherein the electronic unit (3) is arranged to output a warning signal from a comparison of the measure with at least one comparison value.

8. Apparatus according to claim 7, characterized in that the

Electrode assembly (2) is designed as a by a patient (1) wearable garment, in particular as a pair of pants, which is preferably designed as underpants, in which at least a portion of the electrodes (4) are arranged in the region of the upper waistband or as a belt is formed and the electrodes (4) in the attracted state surrounding the pelvis and the bladder of a patient.

9. Device according to one of the preceding claims 7 or 8, characterized

characterized in that at least a part (4a) of all the electrodes (4) in the region of the trouser legs, in particular in their lower bounds

are arranged.

10. Device according to one of the preceding claims 7 to 9, characterized

characterized in that at least one electrode of the

Electrode assembly (2) is arranged on a cable and in the body of a patient (1) is insertable.

11.Vorrichtung according to one of the preceding claims 7 to 10, characterized

in that the electronic unit (3) has a signaling unit with which a signal dependent on the bladder volume can be displayed, in particular optically and / or acoustically, in particular for a patient.

12. Device according to one of the preceding claims 7 to 11, characterized

characterized in that the electronic unit (3) is adapted to provide additional switching signals for external expansion devices, in particular of electrically controllable valves.