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    APPLIANCE AND PROCESS FOR ELECTRO IMPEDANCE TOMOGRAPHY. The present invention relates to an EIT apparatus with a variety of electrodes (4) that can be applied to a body and with an algorithm for reconstructing the impedance distribution of the body in the plane of the electrodes. The control unit (10) of the EIT device, due to the proper programming, is prepared so that from the measurement signals (U (1) U (M)) of all the measurement channels, it can continuously determine at least one specificity ( and (1) and (M)) and correct measurement signals of the measurement channels on the basis of specificities or adapt the reconstruction algorithm on the basis of specificities.
    公开号:BR102012016380B1
    申请号:R102012016380-2
    申请日:2012-07-02
    公开日:2021-04-06
    发明作者:Yvo Garber
    申请人:Drager Medical Gmbh；
    IPC主号:
    专利说明:

    [0001] [0001] The present invention relates to an electro-impedance tomography apparatus with a variety of electrodes applied to a body, with command and measurement circuits to supply alternating current or alternating voltage to the electrodes and voltage or voltage signals. current accepted by the electrodes that will be registered as measurement signals, and with a control unit that is connected with the control and measurement circuit and by an appropriate programming is prepared to always supply a pair of electrodes with alternating current or with an alternating voltage, the voltage or current signal of each pair of electrodes being integrated from all other pairs of electrodes as a measuring signal of a measuring channel and the pair of electrodes to be fed will be allowed to pass successively through the variety of electrodes to integrate and process measuring signals (U1, ..., Um) in this way in a variety of measurement channels M (K1, ..., Km) and to, from this result , reconstruct as a reconstruction algorithm the distribution of the body impedance in the plane of the electrodes.
    [0002] [0002] An electro-impedance tomography device (EIT device) is now known, for example, from the European patent EP 1 000 580 A1, which serves to register an "electro-impedance tomographic image" of a cross-section of a patient's body.
    [0003] [0003] Electro-impedance tomography is a process for reconstructing impedance distributions or impedance changes in relation to a reference distribution in bodies that conduct electricity. For this purpose, a variety of electrodes will be applied to the conductive surface of the examined body, and normally the control unit, constituting a digital signal processor, causes subsequent electrodes, always in the form of an adjacent (preferably) pair, to be supplied. with an alternating electric current (for example, 5 mA with 50 kHz) and the electrical voltages will be registered in the remaining electrodes, being distributed to the control unit. By combining the measured values of the voltage in the subsequent and reversing current supplies, with appropriate algorithms, the impedance distribution or its modification in relation to a reference distribution can be reconstructed. In typical cases, an equidistant annular distribution of 16 electrodes will be used, which, for example, can be placed on a band around a patient's body. Alternating current is always fed to two neighboring electrodes and between the remaining pairs of de-energized electrodes the voltages are measured and are received by the control unit. By rotating the points of the current supply, a variety of measured voltage values are received, from which a two-dimensional interface of the impedance distribution can be reconstructed with respect to a reference in the plane of the electrodes.
    [0004] [0004] Electro-impedance tomography finds increasing use in research medicine. Typical EIT devices employ 8, 16 or 32 electrodes for data acquisition, with current (voltage) applied to two or more electrodes and the resulting voltage (current) will be measured between the remaining electrodes. Then, the first variant will be analyzed. The second variant can be considered in a similar way by the exchange of current and voltage as power and measurement quantity. By combining different feeds and measurements it is possible to generate a signal vector from which, by means of an appropriate algorithm, the impedance distribution can be determined, that is, in the functional EIT unit, the relative change in the distribution impedance with respect to a reference value in the plane of the electrodes. The latter procedure will be used in the state-dependent chest EIT, in which N electrodes are applied in a ring shape around the chest in order to reconstruct the comparison of the signal vectors with different pulmonary states (for example, at the end of inspiration and at the end of expiration) an interface of the relative impedance change resulting from ventilation that represents a measure for the regional distribution of lung ventilation. The components of the signal vector, that is, here the voltages constitute an unmistakable combination of the pair of electrodes of the current supply and the pair of electrodes of the voltage supply to which they are allocated. This combination is referred to here as the channel, that is, the measurement channel. Frequent use is verified with the so-called adjacent data capture, where between two adjacent electrodes current will be fed and between the remaining pairs of adjacent electrodes the voltages will be measured. This results from 16 current supplies and 13 measuring pairs in all 16 * 13 = 208 measuring channels, as shown in figure 1. Based on reciprocity with the replacement of current supply and voltage measurement, only 104 from there depend in a linear sense. From the channel voltage measurements, the measurement value - voltage vector will be formed from which a tomographic image (frame) can be calculated. The neighboring DAQ mode stands out for its high sensitivity to changes in relative impedances, however, it has the disadvantage that in part there are very small voltages that can contain faults. Longer distances between power supply and / or voltage measurement in this sense are more robust, however, sensitivity is generally lost.
    [0005] [0005] From the mathematical-physical point of view, the EIT unit is an inverse and non-linear problem of poor conformation. This means that very small faults in the measured marginal voltages are manifested in the form of very large faults in the inverse solution of the distribution of the conductive capacity, that is, the distribution of impedance, and the solution generally does not always depend on marginal voltages measured with failures. Also, in the case of linearization of the functional chest EIT, in the case of changes in the state of small extension of the lung by ventilation compared to a referential state of the lung, deficient regulation remains preserved. In the matrix representation of the reconstruction this is generally reflected by the deficient condition of matrices that describe the connection of capacitation changes (that is, impedance changes) inside the examined object as to changes in the measurement voltages at the margin of the examined object in the case of known power supply. For this reason, mathematical procedures such as regularization are used to alleviate deficient conditions, but this results in a restriction of the solution area and a worsening of spatial resolution.
    [0006] [0006] Typically, a compromise is sought between robustness compared to measurement and resolution failures. The intensity of the smoothing is controlled through a so-called smoothing parameter that will be suitable for the signal-to-noise ratio (SNR). Eventually, values measured with differentiated noise can also be weighted in a different way in the reconstruction process and start to constitute with the correlation matrix, in a similar way as with a weighted average. 〈X〉 = (Σ xi, / σi 2) / (Σ1 / σi 2) with σi as the statistical failure of a large measurement xi. The SNR is primarily an instrument-specific quantity, for which the hardware of many EIT systems is optimized. As a re-construction, therefore, a fixed reconstruction standard will usually be used, once generated, which takes into account the SNR, for example, in weighting and / or regularization. For laboratory experiments with a very constant and idealized environment, this is usually sufficient. In the practical day-to-day practice of clinical use, however, the concept of a fixed reconstruction standard often appears to be insufficient. In particular, it is evident that a consideration of statistical failures (SNR) for the reconstruction standard alone is not always sufficiently robust for the practical clinical use of the EIT. With the electronics and modern calculation technique the noise factor is generally not a limiting factor for a successful measurement. Measurement flaws, which form clear artifacts in EIT images, are generally systemic in nature. These systemic measurement failures are, for example, produced by voltages called common mode (Common Mode) or by "Cross-Talk" (interactive conversation) - (the capacitive indication can often be well shielded). In addition, these measurement failures change over time. This precise quantity of systemic measurement errors, in this case, is typically not known, so that a correction of the stresses themselves is generally not possible. Previous EIT systems have been largely employed, in laboratory conditions, with phantoms or in healthy voluntary guinea pigs, where the share of relative systemic failure is often very small. For this reason, these failures are not taken into account in the existing EIT reconstruction standards. However, in daily clinical practice, it occurs in critically ill patients with pulmonary pathology that the share of relative systemic failure of measurement voltages can be very high. Ignoring these flaws could then result in huge artifacts in reconstructed EIT images that make clinical interpretation impossible.
    [0007] [0007] The adequacy of reconstruction in the emergence of measurements with a high failure rate will normally be employed in applications where these occurrences are expected. When, for example, an average of 100 measurements must be formed, and knowing that from measurement 33 that it was a wrong "measurement", it will be discarded, and then the average of the remaining 99 measurements will be formed. However, in the EIT, until now, this type of reconstruction normalization has not been carried out. In all previous published reconstructions, a complete set of data from all measurement channels is taken into account, generally taking into account the weighting on the basis of statistical measurement failures through the correlation matrix taking into account the SNR, and failures of systemic measurements in the EIT are ignored from current reconstruction standards.
    [0008] [0008] Therefore, it is an object to develop an EIT device with a process for continuous adaptation of the reconstruction standard in statistical and / or systemic measurement failures. This EIT system should analyze the measurement data of all channels for possible measurement errors and, if necessary, adapt the reconstruction standard to the respective incident failure situation in order to guarantee a reconstruction to the greatest extent free from failures. , that is, of artifacts and, therefore, clinically interpretable of EIT images for the entire duration of the measurement. Initially, the user must additionally be informed of the status of the measurement. In particular, in the case of failures that cannot be corrected, the user should be advised that EIT measurements cannot be clinically evaluated.
    [0009] [0009] To solve this task, an electro-impedance tomography apparatus with the characteristics of claim 1 and a corresponding process with the characteristics of claim 11 are used. Advantageous modalities are indicated in the dependent claims.
    [0010] [00010] The object of the invention is an EIT device in which a process is implemented for the continuous adaptation of the reconstruction standard and / or the measuring signals in flawed measurements, both of a statistical and especially systemic nature. The measurement data of all channels will be continuously analyzed for possible measurement failures and, if necessary, the reconstruction standard will be appropriate to the respective failure situation, with which EIT images will be ensured in a broad manner free from interference and artifacts. for the entire duration of the measurement process. The user will be informed by a graphic and / or alphanumeric representation of a quality index on the quality of the measured data. In particular, in the case of incorrigible failures, the user should be advised that EIT measurements cannot be clinically evaluated. Episodes of EIT image sequences that are not correctable and markedly marked by faults, including EIT data curves for shorter time periods and / or tendency presentations over longer periods of time, will be marked separately in the indication and do not participate in the graduation of corresponding indicator elements.
    [0011] [00011] The figures show: Figure 1 - schematic presentation of the data record for a 16 electrode EIT system with drawn equipotential lines, between the pair of current supply electrodes and the pair of voltage measuring electrodes, Figure 2 - schematic presentation of the EIT device with the process for adapting the EIT reconstruction of faulty data, Figure 3 - schematic presentation of indicator elements of EIT images and curves / trends derived from EIT data with quality information about corresponding data, Figure 4 - a spatial image with a large artifact generated from a 30-second data record with a 16 electrode EIT system without adaptation to incident measurement failures, predominantly systemic. Figure 5 - a presentation of the specific quality parameters of 208 channels, Figure 6 - a spatial image without artifact, generated from the same data set as for figure 4, however, with suitability for systemic measurement failures, predominantly incident and, Figure 7 - schematic presentations of the probability distributions of the eα measurement channel properties (for all m or a subquantity of m), determined from a representative set of clinical data, as well as a simple functional connection
    [0012] [00012] The invention creates an EIT device and process with the following execution characteristics corresponding to figures 2 and 3: 1. The voltages 7 of all measuring channels M will be continuously examined for possible faults. This can be done by comparing α = 1 ··· N properties in α (Um) (11), the measured voltages of all channels m = 1 ... Μ in comparison with the desired values to be predicted and / or theoretical regions esoll m α (15). The theoretical region can, for example, be derived from device parameters and / or theoretical considerations such as reciprocity and / or by analyzing a large data set of EIT measurements from clinics and / or laboratory tests with interferences controlled failures. Examples of measurable and derivable properties of measured voltages are, of course, on the one hand, the determined SNR, but also voltage leaks or changes of these, of the average indication, phase, ie real and imaginary portion of the voltage, applicable to Cross evaluations -Talk determined from measuring voltages, evaluations of common mode (Common Mode) of voltages, reciprocity of measuring voltages, voltage derivations, fluctuations in the supplied current, correlations between voltage and ventilation data, if any, extension and phase of the impedances of epidermal contact electrodes, characteristic properties of values and phase distributions of the frequency spectra of the measurement channels of different channels over a certain period of time such as, for example, a maximum, standard deviation, shape of the spectral distributions, etc. It should be noted that the N properties of the measurements do not necessarily need to be independent of each other. Systemic failures, such as common mode (cross-mode) or crosstalk (cross-talk) failures, can be reflected in several properties, however, not necessarily. 2. An adaptation method consists of certain properties N the systemic fault plots of the stresses M and to directly correct the stresses. 3. Another method of adaptation is channel-specific adaptation of the reconstruction standard. From the comparison of α = 1 ··· Na of properties determined in α each channel m = 1 · ..Μ with desired values previously derived in an empirical and / or theoretical way esoll m α will be determined channel specific and specific parameters properties that
    [0013] [00013] In the following, the invention will be explained based on an example of execution in connection with the figures.
    [0014] [00014] Figure 3 presents some examples for EIT data indicator elements with quality information, being the schematic presentation. A representation of bars 24 of any orientation can be represented in monochrome or with color codes, where the full bar represents good quality and the empty bar represents poor quality or according to the definition it can be full or empty also in reverse position . The color of the bar, in case of certain threshold overtakes (for example, for good = green, medium = yellow, deficient = red) can also change the color. It would also be possible to indicate lamps 25 (poor quality = red, medium quality = yellow, good quality = green). Of course, alternative encodings and / or numbers of indicator lamps are imaginable. Another indication variant is, for example, a full level indication 28 or a sectorial presentation 29, selectively monochromatic or color-coded. Alphanumeric values can be found, for example, directly in EIT images (30) or images derived from EIT data or they can be in graphical representations such as, for example, within a fill level indication 28. The term trend representations is understood here graphs of data based on EIT for longer periods of time, for example, several minutes to hours 33 and with curves here we can understand quantities of fast variation of seconds or few minutes 32. Episodes with such poor data quality that notwithstanding adaptation processes, the results of the reconstruction have a high failure rate or can constitute these indexes being separately marked 34. The reconstructed values, for example, of impedance curves 32 of the segment of poor data quality will not be used for the graduation of indication 35. The same also applies to trend representation 33, for example, of impedance changes. a (sectoral courses) of terminal inspirational impedance changes. The values probably with a high index of failures in the sectoral courses 36 in the marked episode of deficient data quality 34 also do not participate in graduation. It is also possible in trend presentations 33 of quantities based on EIT in episodes of deficient data quality 34, to determine the values at a fixed value 37 or to perform interpolation 34.
    [0015] [00015] Based on the following example, the process quality index for the specific determination by channel and the global quality parameters, as well as the adaptation of the reconstruction standard for this example will be explained. Variations of this example yield similar results. Here, the following channel-specific properties have been employed for a 16-EIT electrode system with 208 measurement channels in the adjacent DAQ mode: em1: real portion Re (Um) m - 1 ... 208, of stresses Um mediated by a fixed time window. The time window is about 30 seconds and contains several inspirations and breaths, in 2: phase Øm = atan (lm (Um) / Re (Um)) m = 1 ... 208, of voltages Um, mediated by a fixed time window, in 3: value of the maximum tension max (Um) m = 1 ... 208, of the stresses Um, mediated in a fixed time window, in 4: Common Mode Relative Faults
    [0016] [00016] The specific quality index was determined by the following calculation standard:
    [0017] [00017] As a variation of this standard, a hysteresis threshold or other more complex variants may also be agreed. This depends on the respective hardware and also on the experience in the behavior of clinical data. To determine the interface parameters cm α d m α an evaluation of clinical studies was carried out on 400 data sets. The characteristics and m α distributions were determined, represented schematically in the example of figure 7a) -7c).
    [0018] [00018] It was determined that a cut in α should always be adjusted with a value of in α, 99.5% of the data being located below (illustration 7a, for example, reciprocity) or above (figure 7b, for example, real portion voltage) or in a range (figure 7c, for example, phase) are located according to the region that is considered to have progressive systemic failures. For the type of distribution in figure 7a, mention should be made, for example, of reciprocity. Ideally, it is 0, and values that are too large indicate systemic measurement failures, the cut-off ratio at the upper end. For distribution type 7b), for example, the actual voltage portion should be mentioned. The larger this portion, the more unlikely it will be a high systemic failure portion, which is the cut-off point for values that are too small. For distribution type 7c) the phase must be mentioned. It has a diffusion around an average value that depends mainly on the frequency of the fed current used on the average impedance of epidermal contact electrode and analog electronics. In the case of a large magnetic coupling or Crosstalk, very large negative and positive phases may appear, which would indicate high portions of systemic failures. The decay value dm α fixes the quality index area between 0 and 1, that is, the region of the hysteresis itself, and avoids any flicker that, in the case of properties in α, would be close to the intermediate value in α and the function saltiform of qm α between 1 and 0, in the intermediate value. An alternative variant of determining interfaces would also be the use of the so-called "Bootstrapping" (initial load) determining cuts for all to a specificity, then evaluating through the data set the distribution of the systemic failure probability of the properties not mentioned, and through these factors determine the cuts for the greatness left aside. Then this greatness is added, leaving another one in its place and the process is repeated until all the cuts in this way have been determined. An iterative procedure is also possible in this case. Regardless of the determination of the cuts in a large set of clinical data: the concrete values of the cutting parameters c m α d m α depend on how the concrete hardware of an EIT system reacts to the measurement conditions in everyday clinical practice.
    [0019] [00019] The channel-specific qm quality index was determined here from the product of the characteristic-specific qm α quality index and channel:
    [0020] [00020] This is a conservative approach as a property with a high failure rate can result in large errors in the EIT image and any correlations between different specifics would be reduced. Additionally, the channel-specific quality index applied to neighboring channels m ± 1 of a channel m with extreme strong interference can, conservatively, also be set to 0. In this example, this procedure has been dispensed with.
    [0021] [00021] The analysis of the specific data quality per channel according to the procedural segments 1) to 3) are presented by the specific quality parameters per channel and gathered and illustrated in figure 5. It can be seen that most channels effectively they presented almost flawless measurements (qm - values close to 1), three channels showed moderate systemic failures, three channels, however, presented massive systemic failures, so that they were allocated the qm values of 0 as detailed above- explained. It should be noted that in this measurement there were no major statistical flaws, that is, noise. The SNR was in the expected range. The cause in this case was a systemic Common Mode failure in the voltage measurement.
    [0022] [00022] The specific qm quality indexes per channel were used to define a systemic failure weighting matrix: W = diag (q1, q2, ...., q208).
    [0023] [00023] To reconstruct the vector n Δρn of the relative change in impedance of the change in relative voltage n Δun, a Newton-Raphson single step process was used, based on a sensitivity matrix. The sensitivity matrix S was determined from a finite element model of the chest using the linearized Geselowits relationship. The adaptation of the reconstruction matrix A to the concrete systemic failures found, is verified by the integration of the systemic W-weighting matrix in the determination of the reconstruction matrix: A = r (ST WS + λLT L) -1 S t W, Δρn (t) = AΔu n (t)
    [0024] [00024] The L matrix designates the regularization matrix. The scale quantity λ designates the regularization parameter. The R matrix represents a filtered registration matrix of the FEM system in relation to the Pixel system of the EIT image.
    [0025] [00025] Figure 4 shows an EIT image generated from the relative voltage changes between pulmonary states of final inspiration and final expiration of approximately 30 seconds of data recording in a clinic in the adjacent DAQ mode with an EIT system with 16 electrodes ( 208 channels) without using the above described process of adapting the reconstruction standard, that is, for this procedure the reconstruction standard indicated above with W = I was used, where I represents the 208 dimensional identity matrix. This means an acceptance in the sense that all the measured channels are systematically free from failures, as, for example, also in the frequently used overhead projection. The horizontal structure, shown in figure 4, should be framed primarily as an artifact that was produced by the three channels with strong interference with qm = 0. The large artifact has nothing to do with the effective distribution of the impedance change that is valid as a measure for the regional ventilation. A clinical evaluation of this image would lead to a clear interpretation of failures.
    [0026] [00026] In Figure 6, the EIT image is found, which is based on the same measurement data with faults as the image in figure 4, with the used adaptation of the reconstruction standard according to the formula above by including the quality index determined in the quality analysis in figure 5 in the fault weighting matrix - W. The complete suppression of the contributions of the three channels qm = 0 produced the disappearance of the artifact in the EIT image figure 6. Here is a normally ventilated left lung (CT-thorax convention) cross section: in the image, on the right side), but in the opposite direction a poorly ventilated right lung in the dorsal region, coinciding with clinical X-ray results. By using the process segment 4), which will be explained later for this example of execution, a global quality index of Q = 0.5 was allocated, which corresponded to the average damage quality. Because even if the EIT data had been interpreted using the adaptive reconstruction process, the user must be informed about the fact that erroneous measurements were present. A cause analysis resulted in high portions of the Common Mode in the electrode pair 11, 12 based on the deficient impedance of electrode-epidermal contact electrodes 12. A proposal to test the electrode contact according to the process segment 8 can, in these cases, bring help.
    [0027] [00027] Systemic failures have proven to be quite constant over time. A new adaptation is especially indicated when there is a worsening of a quality index to a great extent, for example, Δqm> 0 8, because a deficient channel can, eventually, generate a strong artifact. Conversely, it will only be necessary to adapt clearly improved channels in a large number (greater than 6, for example), proceeding to adapt them, since only the precision, compared to the previous solution without these channels, would be statistically improved to a small extent. .
    [0028] [00028] For the determination of the global data quality index, the following global specificities were used in this example: E1: Average value of the specific quality index per channel; E2: maximum values of the specific property of the channel at 6: E3: dynamic area (maximum stress to minimum stress ratio); E4: technical operation status (Flag issued by the EIT 0 or 1 system).
    [0029] [00029] Until the indicator of technical operating conditions that was pointed out by the device, a determination was made in an analogous way with the specific channel properties of the clinical data sets in more than 400, the distributions of the global data quality parameters and in an analogous way and in a similar way the cut-off values and decay intensities E = C, D) analogous to the above described and in the second iteration by analysis of experts of EIT images belonging an empirical adequacy was made. The determination of the global data quality parameters Q was verified with the analogous formula as for the channel-specific data quality parameters qm α:
    [0030] [00030] The following values resulted Q1 = 0.89, Q2 = 1, Q3 = 0.56, Q4 = 1. The global Q quality index was also determined from the product of the specific global Qβ quality index of properties:
    [0031] 1. Alimentação de corrente entre eletrodos energizados 2. Rotação da alimentação de corrente 3. Rotação da medição de tensão por posição de alimentação de corrente. 4. Eletrodos + cabo para medição EIT no sujeito 5. Aparelho EIT 6. Transporte de dados, fluxo de dados 7. Vetor do valor de medição das tensões U de todos os canais M de um quadro (Frame) 8. Vetor com dados operacionais de um quadro 9. Conjunto de dados de tensões e informações de operação de ao menos um quadro 10. Computador 11. Determinação das propriedades específicas de canal dos jogos de dados 12. Determinação das propriedades globais do conjunto de dados 13. Determinação dos parâmetros de qualidades específicos por canal e propriedades 14. Determinação dos parâmetros de qualidades globais das propriedades globais 15. Banco de dados, ou seja, relação com valores deseja-dos/alcances teóricas das propriedades específicas por canal 16. Banco de dados, ou seja, relação com valores deseja-dos/alcances teóricas de propriedades globais 17. Determinação do índice de qualidade específico de canal 18. Análise do comportamento temporal do índice de qualidade específico de canal 19. Determinação do índice de qualidade global para a medição 20. Decisão para adaptação da norma de reconstrução ou utilização continuada dos atuais índices de qualidade específicos por canal com base nas alterações, comparado com valores de umbral 21. Adaptação da norma de reconstrução mediante inclusão do índice de qualidade específico de canal 22. Reconstrução dos dados EIT das tensões do jogo de dados 23. Indicação dos dados EIT com medida de qualidade 24. Indicação de barras do índice global de qualidade Q 25. Indicação por lâmpada do índice global de qualidade Q 26. Indicação apenas por cores e/ou codificação de claridade do índice global de qualidade Q 27. Indicação de barras com indicação quase contínua colorida e/ou codificada de qualidade do índice global de qualidade Q 28. Indicação de nível de enchimento com valos alfanumérico do índice global de qualidade Q 29. Indicação setorial do índice global de qualidade Q 30. Imagem espacial com indicação de qualidade alfanumérica 31. Espaço de tempo curto de um período de tempo longo na apresentação tendencial dos cursos espaciais 32. Curva de impedância do segmento de tempo curto (por exemplo, aproximadamente 1 minuto) com ventilação 33. Apresentações tendenciais de diferentes grandezas derivadas de EIT por um período de tempo mais longo (por exemplo, 10 minutos) 34. Episódio marcado com qualidade deficiente de dados (não interpretáveis) 35. Valores falhos da curva de impedância no episódio de qualidade dados deficiente (a adaptação da reconstrução não mais foi possível, por exemplo, em virtude de um número muito grande de erros) que não participaram na graduação da indicação 32 e, portanto, não são indicados integralmente 36. Valores falhos para cursos espaciais no episódio de graduação deficiente não participante 37. Fixação de valores de uma representação tendencial para um valor predeterminado em um episódio de qualidade deficiente de dados 38. Interpolação de valore oriundos de uma representação tendencial com o último valor da representação tendencial antes do episódio de deficiente qualidade de dados 39. Distribuição assimétrica da probabilidade para uma eα propriedade de canal , por exemplo, reciprocidade e tensões de modo comum (Common Mode)(ver acima) com corte no caso de valores demasiado grandes 40. Distribuição assimétrica de probabilidade para uma propriedade de canal e α, por exemplo, parcelas reais, das quatro menores tensões por paciente (ver acima) com corte no caso de valores demasiado pequenos 41. Distribuição simétrica de probabilidade para uma pro-e priedade de canal e α, por exemplo, fases das tensões com valor médio deduzido ou distribuições dos f-(duplas) da modulação com cortes em valores muito grandes apresentados. [00031] A value of Q = 0.5 resulted, registered in the upper left part of illustration 6. This is an average region. The user now knows that the measurement can be interpreted based on the adaptation of the reconstruction standard, but he also knows that channels with systemic faults are present. REFERENCE LISTING 1. Power supply between energized electrodes 2. Power supply rotation 3. Rotation of voltage measurement by current supply position. 4. Electrodes + cable for EIT measurement on the subject 5. EIT device 6. Data transport, data flow 7. Vector of the measured value of the U voltages of all the M channels of a frame (Frame) 8. Vector with operational data from a frame 9. Voltage data set and operating information for at least one frame 10. Computer 11. Determination of the specific channel properties of the craps 12. Determination of the global properties of the data set 13. Determination of specific qualities parameters by channel and properties 14. Determination of global quality parameters of global properties 15. Database, that is, relationship with desired values / theoretical ranges of specific properties by channel 16. Database, that is, relation to desired values / theoretical ranges of global properties 17. Determination of the channel-specific quality index 18. Analysis of the temporal behavior of the channel-specific quality index 19. Determination of the overall quality index for measurement 20. Decision to adapt the reconstruction standard or continued use of the current specific quality indices per channel based on the changes, compared to threshold values 21. Adaptation of the reconstruction standard by including the channel-specific quality index 22. Reconstruction of the EIT data from the dice game stresses 23. Indication of EIT data with quality measure 24. Indication of bars of the global quality index Q 25. Lamp indication of the global quality index Q 26. Indication only by color and / or light coding of the global quality index Q 27. Indication of bars with quasi-continuous color and / or coded indication of the quality of the global quality index Q 28. Indication of level of filling with alphanumeric values of the global quality index Q 29. Sectoral indication of the global quality index Q 30. Spatial image with indication of alphanumeric quality 31. Short time span over a long period of time in the trend presentation of space courses 32. Impedance curve of the short time segment (for example, approximately 1 minute) with ventilation 33. Trend presentations of different quantities derived from EIT over a longer period of time (for example, 10 minutes) 34. Episode marked with poor data quality (not interpretable) 35. Fault values of the impedance curve in the episode of data quality deficient (the reconstruction adaptation was no longer possible, for example, due to a very large number of errors) that did not participate in the graduation of indication 32 and, therefore, did not are fully indicated 36. Faulty values for space courses in the episode of deficient non-participating graduation 37. Setting values of a trend representation to a predetermined value in an episode of poor data quality 38. Interpolation of values from a trend representation with the last value of the trend representation before the episode of poor data quality 39. Asymmetric probability distribution for an eα channel property, for example, reciprocity and common mode voltages (see above) with cutoff in case of too large values 40. Asymmetric probability distribution for a channel property and α, for example, real plots, of the four lowest stresses per patient (see above) with cutoff in case of values that are too small 41. Symmetric probability distribution for a channel property and α, for example, phases of the stresses with deducted mean value or distributions of the f- (doubles) of the modulation with cuts in very large values presented.
    权利要求:
    Claims (13)
    [0001]
    Electro-impedance tomography (EIT) apparatus comprising: a variety of electrodes applicable to a body; control and measurement circuits to supply alternating current or alternating voltage to the electrodes and receive voltage or current signals accepted by the electrodes as measurement signals; a control unit that is connected with the control and measurement circuit configured to control an alternating current supply or alternating voltage to a pair of electrodes as a pair of supply electrodes and configured to receive the measured voltage signal, or current signal measured from each pair of electrodes of all other pairs of electrodes as measurement signals, and exchange the pair of electrodes fed successively by the plurality of electrodes to receive and process measurement signals (U1, ..., One) of a plurality of (M) individual measurement channels (K1, ..., Km) to reconstruct from there with a reconstruction algorithm the body impedance distribution, characterized by the fact that the control unit is further configured to determine continuously at least one specificity (ea1, ..., eaM) of a set (α) of specificities to determine channel-specific quality parameters (q1, ..., qM) by comparing at least one specificity of each channel with predetermined desired values, specificities comprising signal-to-noise ratio of measurement signals, abnormal value of measurement signals, average value of measurement signals, real or imaginary phase or portion of the measurement signal, signal crossstalk measurement, common mode of measurement signals, reciprocity of measurement signals, deviation of measurement signals, fluctuation of current supply and epidermal contact electrode impedance value and phase, each of said measurement signals (U1, ..., One) of all measurement channels and configured to correct measurement signals of said measurement channels on the basis of said at least one specificity by subtracting certain systemic errors and adapting the reconstruction algorithm on the basis of at least minus one property including the channel-specific quality specificities (q1, ..., qM) among the channel-specific specificities in the reconstruction algorithm in a mat riz that comprises a weighting matrix W (q1, ..., qM) that comprises the specific specificities of channel quality (q1, ..., qM), in which the control unit determines yet another specificity in order to determine N properties in α (UM) (a = 1, ..., N) of the set (α) of specificities in all measurement channels for each signal of measurement (U1, ..., UM) and compares the N properties with desired values or with desired ranges and soll m α previously determined or with both the desired values and desired ranges previously determined, to provide results of a comparison, and corrects the measured signals from the measurement channels based on the results of the comparison based on the specifics or adjust the reconstruction algorithm on the basis of the specifics; where the control unit determines, by comparing the specificities determined in α for each channel m = 1, ..., M with previously determined desired values or reaching desired values and soll m α, quality parameters
    [0002]
    Electro-impedance tomography (EIT) apparatus according to claim 1, characterized by the fact that the control unit continuously updates a determination of α specificities or specific specificity parameters derived therefrom or channel specific quality parameters combined or any combination of the specifics, the specific quality parameters of specificities derived therefrom and the specific quality parameters of the channel, especially with the determination being made through an accompanying time window
    [0003]
    Electro-impedance tomography (EIT) apparatus according to claim 1, characterized by the fact that the control unit continuously determines several global specificities Eß, ß = 1 ... G of the measurement signals of the measurement channels or properties or technical operational quantities of the electro-impedance tomography device or any combination of the measurement signals of the measurement channels, its specificities and technical operational variables of the electro-impedance tomography device, with the global specificities being at least one of the selected specificities of the specificity group including maximum, minimum or average values or combinations of α specificities and channel-specific qm quality parameters and operating current intensities, reinforcement factors, dynamic range of measurement signals, operating frequencies and the difference standard of EIT images with and without adaptation of the reconstruction algorithm, than, in addition, the control unit further compares the global specificities E β with expected desired values or ranges of desired values E soll β or with both the expected desired values and ranges of desired values, to provide results of a comparison and based in the results of this comparison, determine global quality parameters Qβ (Eβ).
    [0004]
    Electro-impedance tomography (EIT) apparatus according to claim 3, characterized by the fact that the control unit combines the global quality parameters Qß (Eß) into a global quality index Q (Q1, ... HQ), by forming an arithmetic or geometric mean value of the global quality parameters, the control unit standardizing a global quality index in an interval and using the global quality index to adjust the quality of EIT measurements.
    [0005]
    Apparatus for electro-impedance tomography (EIT) according to claim 4, characterized by the fact that the control unit displays the global quality index in a graphical or alphanumeric form on a display screen.
    [0006]
    Apparatus for electro-impedance tomography (EIT) according to claim 4, characterized by the fact that the control unit marks time intervals separately in which the quality index is located below a predetermined minimum criterion for derived variables, whose variables are derived from the measured impedance distribution and which develop over time displayed on a display screen, and substitute values for the temporal analysis of values with values derived from adjacent intervals, for example, by interpolation or averaging or by default values to provide substituted time slots, with replaced time slots marked separately.
    [0007]
    Apparatus for electro-impedance tomography (EIT) according to claim 1, characterized by the fact that adapting the reconstruction algorithm comprises forming an adaptation of the reconstruction matrix A with the integrated weighting matrix W (q1, ..., qM) , on what: a Newton-Raphson method based on a sensitivity matrix is used to reconstruct a vector Δρn of the relative impedance change of the relative voltage change Δun, with Δρn (t) = A x Δn (t); the adaptation of the reconstruction matrix A is in the form: A = R (STWS + ALTL) -1STW, and the sensitivity matrix S is determined from a finite element model (FEM) using the linearized Geselowits relationship, the matrix L designates a regularization matrix, the scalar variable λ designates a smoothing parameter, and matrix R represents a filtered registration matrix from the FEM system to the pixel system of the EIT image.
    [0008]
    Process for evaluating measurement signals from an electro-impedance tomography (EIT) device, the process comprising: provide a variety of electrodes that can be applied to a body, command and measurement circuits to supply alternating current or alternating voltage to the electrodes and to receive voltage or current signals received by the electrodes; connect a control unit to the control and measurement circuits; supply a pair of electrodes, such as a pair of supply electrodes, with alternating current or alternating voltage with the control unit; receiving the measured voltage signal or measured current signal, as a measurement signal for each pair of electrodes of all other pairs of electrodes as measurement signals; alternate the pair of supply electrodes successively to pass through the variety of electrodes and then record measurement signals (U1, ..., Um) in a number of M measurement channels (K1, ..., Km); process the measurement signals (U1,…, UM) received in the number of M measurement channels (K1,…, KM), including reconstructing the impedance distribution of the body in an electrode plane of the electrode variety, with an algorithm of reconstruction with the control unit; characterized by the fact that the control unit is further configured to continuously determine at least one specificity (ea 1, ..., and M) of a set (α) of specificities comprising signal / noise ratio of measurement signals, abnormal value of measurement signals, average value of measurement signals, phase or real or imaginary portion of the measurement signal, measurement signal crossstalk, measurement signal common mode, measurement signal reciprocity, deviation of measurement signals measurement, fluctuation of current supply and value and phase of the epidermal contact electrode impedances of all measurement signals (U1,…, UM) of all measurement channels; determine, with the control unit, systemic errors of said at least one specificity of the signals and to determine channel-specific quality parameters (q1, ..., qM) by comparing at least one specificity of each channel with predetermined desired values ; and correct measurement signals from said measurement channels on the basis of said at least one specificity by subtracting certain systemic errors and adapt the reconstruction algorithm on the basis of at least one property including the specific quality specificities of the channel (q1, ..., qM) among the specific channel specificities in the reconstruction algorithm in a matrix comprising a W weighting matrix (q1, ..., qM) comprising the specific channel quality specificities (q1, ..., qM), on what the control unit determines yet another specificity in order to determine N esoll properties m α (UM) (α = 1, ..., N) of the set (α) of specificities in all measurement channels for each measurement signal (U1, ..., UM) and compares the N properties with desired values or desired ranges esoll m α previously determined or with both desired values and desired ranges previously determined, to provide results of a comparison, and corrects the measured signals the measurement channels based on the results of the comparison based on the specificities or adjust the reconstruction algorithm based on the specificities; where the control unit determines, from the comparison of the specificities determined in each channel m = 1, ..., M with previously determined desired values or the achievement of desired values in esoll, quality parameters
    [0009]
    Process for evaluating measurement signals from an electro-impedance tomography (EIT) device according to claim 8, characterized by the fact that the control unit continuously updates a determination of the specificities of EM or of the specific quality parameters of specificity derived therefrom or the combined channel-specific quality parameters or any combination of the specifics, the specific quality parameters of specificities derived therefrom and the channel specific quality parameters, especially with the determination being made through an accompanying time window.
    [0010]
    Process for evaluating measurement signals from an electro-impedance tomography (EIT) device according to claim 8, characterized by the fact that the control unit continuously determines several global specificities Eβ = 1 ... G of the measurement signals of the measurement channels, whose technical operational properties or quantities of the electro-impedance tomography device or any combination of the measurement signals of the measurement channels, its specificities and the technical operational variables of the electro-impedance tomography device, with the properties Global values are at least one of the properties selected from the property group that includes maximum, minimum or average values or combinations of the properties and specific qma parameters per channel and operating current intensities, boost factors, dynamic range of measurement signals, operating frequencies and the norm of the difference in EIT images with and without adequacy of the reconstruction algorithm, in addition, the control unit is programmatically prepared to compare the global properties Eß with expected desired values or ranges of desired values Esoll ß, or with both expected values and ranges of values to provide results of a comparison and based on the results of this comparison, determine global quality parameters Q ß (Eß).
    [0011]
    Process for evaluating measurement signals from an electro-impedance tomography (EIT) device according to claim 10, characterized by the fact that the control unit meets the global quality parameters Qß (Eß) in a global quality index Q (Q1, ... HQ), by forming an arithmetic or geometric mean value of the global quality parameters, and the control unit standardizes a global quality index in the interval and employs the global quality index to adjust the quality of the EIT measurements.
    [0012]
    Process for evaluating measurement signals from an electro-impedance tomography (EIT) device according to claim 11, characterized by the fact that the control unit displays the overall quality index in a graphical or alphanumeric form.
    [0013]
    Process for evaluating measurement signals from an electro-impedance tomography (EIT) device according to claim 11, characterized by the fact that the control unit marks time intervals separately for derived quantities, of the measured impedance distribution and its development time, represented in an indication, separately characterizing those time intervals in which the quality index is below a predetermined minimum criterion, or in the representation, and for the temporal analysis of the values making the substitution by values derived from the boundary intervals, by for example, by interpolating or averaging or predetermined values to provide substituted time slots, with replaced time slots being marked separately.
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    同族专利:
    公开号 | 公开日
    GB2492619B|2015-09-16|
    DE102011106405B4|2021-08-12|
    DE102011106405A1|2013-01-03|
    US20130002264A1|2013-01-03|
    GB201207734D0|2012-06-13|
    JP2013013734A|2013-01-24|
    JP5653393B2|2015-01-14|
    US9730607B2|2017-08-15|
    BR102012016380A2|2013-12-03|
    GB2492619A|2013-01-09|
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    法律状态:
    2013-12-03| B03A| Publication of a patent application or of a certificate of addition of invention [chapter 3.1 patent gazette]|
    2018-12-11| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2020-09-29| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2021-02-23| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-04-06| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 02/07/2012, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    DE1020111064056|2011-07-02|
    DE102011106405.6A|DE102011106405B4|2011-07-02|2011-07-02|Electro-impedance tomography device|
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