WO2009124369A1 - Electrical impedance tomography employing additional sources of information - Google Patents
Electrical impedance tomography employing additional sources of information Download PDFInfo
- Publication number
- WO2009124369A1 WO2009124369A1 PCT/BR2009/000095 BR2009000095W WO2009124369A1 WO 2009124369 A1 WO2009124369 A1 WO 2009124369A1 BR 2009000095 W BR2009000095 W BR 2009000095W WO 2009124369 A1 WO2009124369 A1 WO 2009124369A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- tomography
- electrical impedance
- signals
- patient
- information
- Prior art date
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Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/053—Measuring electrical impedance or conductance of a portion of the body
- A61B5/0536—Impedance imaging, e.g. by tomography
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow
- A61B5/0205—Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/316—Modalities, i.e. specific diagnostic methods
- A61B5/318—Heart-related electrical modalities, e.g. electrocardiography [ECG]
- A61B5/346—Analysis of electrocardiograms
- A61B5/349—Detecting specific parameters of the electrocardiograph cycle
- A61B5/352—Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
Definitions
- This invention relates to the tomography field and, more specifically, to the use of data, signals, events and information acquired by different means and equipments for improving the functioning of an electrical impedance tomograph.
- Electrical impedance tomography is a known and broadly used technique consisting of positioning a plurality of electrodes in a region of a patient, injecting electrical excitation signals between at least two of these electrodes followed by the reception of the signals induced in the remaining electrodes, and processing these signals in order to generate an indicative map of the impedance in the region of interest.
- the excitation electrodes are sequenced so as to include all electrodes installed in the patient, the typical duration of each cycle being of about 0.1 second for a 32- electrodes system.
- This period is sufficiently long for the electric signals, received in successive cycles, to be modified in view of factors derived from the functioning of the human body.
- the signals received by the electrodes in each measurement cycle will suffer distortions due to the influence of electrical and mechanical signals originated from the cardiac activity, impairing the reconstitution of indicative images of the impedance in the patient's organism.
- the reconstitution of tomograms can be influenced, by variations in the respiratory cycle, blood oxygenation level, cardiac output and, in the case of cranial tomography, by the electrical currents generated by normal cerebral activity.
- the characterization of factors derived from the physiological activity is particularly used to improve the tomogram itself.
- said information comprise, among others parameters, the electrical signals generated by cardiac activity.
- said information comprise, among others parameters, the variations of electrical impedance resulting from the mechanical ventilation and the blood oxygenation level.
- the nonelectrical values such as those related to blood pressure, mechanical ventilation, blood oxygenation level, etc., are converted into electrical signals and forwarded to the processing unit which generates the tomography image.
- the information related to physiological activities are subjected to pre-processing in one or more independent units, transformed into digital signals and forwarded to the processing unit which generates the tomography image.
- the units that perform said pre-processing are incorporated into the electrical impedance tomograph.
- Figure 1 illustrates a first arrangement of the equipments related to the invention.
- Figure 2 illustrates a second arrangement of the equipments related to the invention.
- the first embodiment of the invention comprises a tomograph consisting of a tomography signal generating and processing unit 12, connected to the patient 10 by means of a set of cables 11 and of an electrode belt (not shown), as well as of a screen 13, whereon the tomography image is displayed by known means, said tomograph receiving information related to other parameters derived from the physiological activity of the patient.
- This information is collected by auxiliary equipments, exemplified in Figure 1 by an electrocardiograph 14, a mechanical ventilation monitor 15, a pressure sensor 16, a blood oxygenation measurer 17, etc.
- the signals provided by said auxiliary equipments are directed to a signal compatibilizing unit 18 provided with processing means and software that transform these signals into a digital format compatible with the tomograph.
- the compatibilizing unit can be a physical or a logical block, being part of the electrical impedance tomograph itself.
- the electrocardiograph can integrate means for analyzing the events associated with heart beat, allowing the detection of arrhythmias, frequencies above or below predefined limits, etc., and forwarding the results of this analysis to the tomograph 12 via the compatibilizing unit 18.
- such analysis can be made by means of said compatibilizing unit, allowing the use of lower costs electrocardiographs.
- the signals associated with mechanical ventilation can be analyzed by the breath monitor or the compatibilizing unit, the result of this analysis being forwarded to the tomograph 12.
- the cardiac output data is normally processed in conjunction with pressure data, the latter can be measured by means of invasive methods
- the information obtained upon monitoring one or more parameters provided by the auxiliary equipments will allow the assessment of the evolution of the patient's conditions, by comparing the current state, defined by the info ⁇ nation resulting from one or more auxiliary equipment, with future states defined by future information, allowing the assessment of the variation of any of the monitored parameters comprising hemodynamic, respiratory, cerebral, cardiac parameters, among others.
- the additional information sources are composed of functional blocks (19a, 19b, ... 19n) inside the tomograph 19.
- Such blocks consist of electronic circuits and storage means recordable with software for the acquisition, conditioning and/or analysis of the signals received by the transducers or electrodes connected to the patient.
- Said functional blocks can be integrated into the tomography boards responsible for the acquisition and treatment of the electrical impedance signals or, in an alternative embodiment, be integrated into dedicated boards, separated from those that carry out the acquisition and treatment of electrical impedance signals.
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- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Biomedical Technology (AREA)
- Medical Informatics (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Radiology & Medical Imaging (AREA)
- Heart & Thoracic Surgery (AREA)
- Physics & Mathematics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
Electrical impedance tomography employing additional sources of information using, in the tomography signal processing and image generating unit, information received by auxiliary equipments concerning the monitoring of one or more parameters related to the physiological activity of a patient comprising, among others, electrical signals generated by cardiac and cerebral activity, electrical impedance variations derived from mechanical ventilation and blood oxygenation level, etc.
Description
ELECTRICAL IMPEDANCE TOMOGRAPHY EMPLOYING ADDITIONAL SOURCES OF INFORMATION
Field of the Invention This invention relates to the tomography field and, more specifically, to the use of data, signals, events and information acquired by different means and equipments for improving the functioning of an electrical impedance tomograph.
Description of the State of the Art
Electrical impedance tomography is a known and broadly used technique consisting of positioning a plurality of electrodes in a region of a patient, injecting electrical excitation signals between at least two of these electrodes followed by the reception of the signals induced in the remaining electrodes, and processing these signals in order to generate an indicative map of the impedance in the region of interest. In each measurement cycle, the excitation electrodes are sequenced so as to include all electrodes installed in the patient, the typical duration of each cycle being of about 0.1 second for a 32- electrodes system.
This period is sufficiently long for the electric signals, received in successive cycles, to be modified in view of factors derived from the functioning of the human body. For example, the signals received by the electrodes in each measurement cycle will suffer distortions due to the influence of electrical and mechanical signals originated from the cardiac activity, impairing the reconstitution of indicative images of the impedance in the
patient's organism.
Similarly, the reconstitution of tomograms can be influenced, by variations in the respiratory cycle, blood oxygenation level, cardiac output and, in the case of cranial tomography, by the electrical currents generated by normal cerebral activity.
Objectives of the Invention
In view of what has been exposed, it is an objective of the invention to provide a method to identify, characterize, quantify, reduce or eliminate the influence of factors derived from the normal physiological activity in the electrical impedance tomogram. The characterization of factors derived from the physiological activity is particularly used to improve the tomogram itself.
It is another object of the present invention to implement an arrangement of equipments that allows the achievement of the objective above.
Brief description of the invention
The objectives above, as well as other objectives, are achieved by the invention by means of forwarding, to the tomography signal processing and image generating unit, the information received by auxiliary equipments concerning the monitoring of one or more parameters related to the physiological activity of the patient.
In accordance with another aspect of the invention, said information
comprise, among others parameters, the electrical signals generated by cardiac activity.
In accordance with another aspect of the invention, said information comprise, among others parameters, the variations of electrical impedance resulting from the mechanical ventilation and the blood oxygenation level.
In accordance with another aspect of the invention, the nonelectrical values, such as those related to blood pressure, mechanical ventilation, blood oxygenation level, etc., are converted into electrical signals and forwarded to the processing unit which generates the tomography image.
In accordance with another aspect of the invention, the information related to physiological activities are subjected to pre-processing in one or more independent units, transformed into digital signals and forwarded to the processing unit which generates the tomography image.
In accordance with another aspect of the invention, the units that perform said pre-processing are incorporated into the electrical impedance tomograph.
Description of the Figures
The other aspects and advantages of the invention will become more evident from the description of the preferred embodiments of the invention and the referred figures, in which:
Figure 1 illustrates a first arrangement of the equipments related to the invention.
Figure 2 illustrates a second arrangement of the equipments related to the invention.
Detailed description of the invention
Referring to Fig. 1, the first embodiment of the invention comprises a tomograph consisting of a tomography signal generating and processing unit 12, connected to the patient 10 by means of a set of cables 11 and of an electrode belt (not shown), as well as of a screen 13, whereon the tomography image is displayed by known means, said tomograph receiving information related to other parameters derived from the physiological activity of the patient. This information is collected by auxiliary equipments, exemplified in Figure 1 by an electrocardiograph 14, a mechanical ventilation monitor 15, a pressure sensor 16, a blood oxygenation measurer 17, etc.
The signals provided by said auxiliary equipments are directed to a signal compatibilizing unit 18 provided with processing means and software that transform these signals into a digital format compatible with the tomograph. The compatibilizing unit can be a physical or a logical block, being part of the electrical impedance tomograph itself.
In accordance with the principles of the invention, the electrocardiograph can integrate means for analyzing the events associated with heart beat, allowing the detection of arrhythmias, frequencies above or below
predefined limits, etc., and forwarding the results of this analysis to the tomograph 12 via the compatibilizing unit 18. Likewise, such analysis can be made by means of said compatibilizing unit, allowing the use of lower costs electrocardiographs. Similarly, the signals associated with mechanical ventilation (airways pressure, breath flow) can be analyzed by the breath monitor or the compatibilizing unit, the result of this analysis being forwarded to the tomograph 12.
The cardiac output data is normally processed in conjunction with pressure data, the latter can be measured by means of invasive methods
(transducer inserted by means of a catheter in the patient vascular system) or by non-invasive methods (sphygmomanometer), by means of a specific auxiliary equipment and of a compatibilizer 18.
The information obtained upon monitoring one or more parameters provided by the auxiliary equipments will allow the assessment of the evolution of the patient's conditions, by comparing the current state, defined by the infoπnation resulting from one or more auxiliary equipment, with future states defined by future information, allowing the assessment of the variation of any of the monitored parameters comprising hemodynamic, respiratory, cerebral, cardiac parameters, among others.
According to the embodiment illustrated in Fig. 2, the additional information sources are composed of functional blocks (19a, 19b, ... 19n) inside the tomograph 19. Such blocks consist of electronic circuits and storage means recordable with software for the acquisition, conditioning and/or analysis of the
signals received by the transducers or electrodes connected to the patient. Said functional blocks can be integrated into the tomography boards responsible for the acquisition and treatment of the electrical impedance signals or, in an alternative embodiment, be integrated into dedicated boards, separated from those that carry out the acquisition and treatment of electrical impedance signals.
Although the invention has been described based on specific exemplificative embodiments, it is understood that modifications can be performed by one skilled in the art, provided that they are comprised within the scope of the claims. For example, the connections between the auxiliary equipments and the tomograph or the compatibilizing unit, or between this unit and the tomograph, could be made without the need of cables, but rather by means of wireless links, in accordance with known techniques, such as radiofrequency loop, infrared or the like.
Accordingly, the invention is defined by the following set of claims.
Claims
1. Electrical impedance tomography employing additional sources of information, characterized by using, in the tomography signal processing and image generating unit, information received by auxiliary equipments, related to the monitoring of one or more parameters concerning the physiological activity of a patient.
2. Tomography, according to Claim 1, characterized in that said parameters comprise the events related to cardiac activity.
3. Tomography, according to Claim 2, characterized in that said events comprise one or more set of signals related to electrocardiogram, cardiac output and blood pressure.
4. Tomography, according to Claim 3, characterized in that blood pressure is measured by invasive methods.
5. Tomography, according to Claim 3, characterized in that blood pressure is measured by non-invasive methods.
6. Tomography, according to Claim 1, characterized in that said parameters comprise the events related to mechanical ventilation of the patient.
7. Tomography, according to Claim 1, characterized in that said parameters comprise the events related to brain activity of the patient.
8. Tomography, according to Claim 1, characterized in that said parameters comprise blood oxygenation values of the patient.
9. Tomography, according to any of the preceding claims, characterized by providing the assessment of the variation of the monitored parameters by means of a comparison between a state defined by said information and subsequent states defined by subsequent information.
10. Tomography, according to Claim 1, characterized in that said auxiliary equipments are connected to the tomography signal processing unit by means of cables.
11. Tomography, according to Claim 1, characterized in that said auxiliary equipments are connected to the tomography signal processing unit by means of wireless links.
12. Tomography, according to Claim 1, characterized in that said auxiliary equipments are integrated into the tomography signal processing unit by means of functional blocks.
13. Tomography, according to Claim 12, characterized in that said functional blocks comprise electronic circuits and storage means recorded with software for the acquisition, conditioning and/or analysis of signals acquired by means of transducers or electrodes connected to the patient.
14. Tomography, according to Claims 10, 11 or 12, characterized in that the signals derived from said auxiliary equipments are forwarded to a signal compatibilizing unit provided with processing means and software that transform these signals into a digital format compatible with the tomograph.
15. Tomography, according to Claim 14, characterized in that said compatibilizing unit is a physical block.
16. Tomography, according to Claim 14, characterized in that said compatibilizing unit is a logical block, being part of the electrical impedance tomograph itself.
17. Tomography, according to Claims 12 or 13, characterized in that said functional blocks are integrated into the tomograph boards responsible for the acquisition and treatment of electrical impedance signals.
18. Tomography, according to Claims 12 or 13, characterized in that said functional blocks are contained in dedicated boards, separated from those that carry the acquisition and treatment of electrical impedance signals out.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BRPI0801014-5 | 2008-04-09 | ||
| BRPI0801014A BRPI0801014A8 (en) | 2008-04-09 | 2008-04-09 | ELECTRICAL IMPEDANCE TOMOGRAPHY USING INFORMATION FROM ADDITIONAL SOURCES |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2009124369A1 true WO2009124369A1 (en) | 2009-10-15 |
Family
ID=40810797
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/BR2009/000095 WO2009124369A1 (en) | 2008-04-09 | 2009-04-08 | Electrical impedance tomography employing additional sources of information |
Country Status (2)
| Country | Link |
|---|---|
| BR (1) | BRPI0801014A8 (en) |
| WO (1) | WO2009124369A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2590321C2 (en) * | 2011-06-30 | 2016-07-10 | Дженерал Электрик Компани | System and method for reconstruction with "soft field" |
| EP3150118A4 (en) * | 2014-05-30 | 2018-01-17 | Rafael Holzhacker | Module for detecting bodily signals |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5311878A (en) * | 1990-06-13 | 1994-05-17 | British Technology Group Limited | Real-time electrical impedance tomography system |
| US20040006279A1 (en) * | 2002-07-03 | 2004-01-08 | Shimon Arad (Abboud) | Apparatus for monitoring CHF patients using bio-impedance technique |
| US20040073130A1 (en) * | 1998-12-10 | 2004-04-15 | Stephan Bohm | Method and apparatus for determining alveolar opening and closing |
| WO2005022138A1 (en) * | 2003-08-28 | 2005-03-10 | University Of Leeds | Eit data processing system and method |
| US20060122523A1 (en) * | 2002-10-17 | 2006-06-08 | Giorgio Bonmassar | Arrangement and method for detecting abnormalities and inconsistencies in a body |
| US20060260611A1 (en) * | 2005-05-18 | 2006-11-23 | Drager Medical Ag & Co. Kg | Device and process for controlling a respirator |
-
2008
- 2008-04-09 BR BRPI0801014A patent/BRPI0801014A8/en not_active Application Discontinuation
-
2009
- 2009-04-08 WO PCT/BR2009/000095 patent/WO2009124369A1/en active Application Filing
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5311878A (en) * | 1990-06-13 | 1994-05-17 | British Technology Group Limited | Real-time electrical impedance tomography system |
| US20040073130A1 (en) * | 1998-12-10 | 2004-04-15 | Stephan Bohm | Method and apparatus for determining alveolar opening and closing |
| US20040006279A1 (en) * | 2002-07-03 | 2004-01-08 | Shimon Arad (Abboud) | Apparatus for monitoring CHF patients using bio-impedance technique |
| US20060122523A1 (en) * | 2002-10-17 | 2006-06-08 | Giorgio Bonmassar | Arrangement and method for detecting abnormalities and inconsistencies in a body |
| WO2005022138A1 (en) * | 2003-08-28 | 2005-03-10 | University Of Leeds | Eit data processing system and method |
| US20060260611A1 (en) * | 2005-05-18 | 2006-11-23 | Drager Medical Ag & Co. Kg | Device and process for controlling a respirator |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2590321C2 (en) * | 2011-06-30 | 2016-07-10 | Дженерал Электрик Компани | System and method for reconstruction with "soft field" |
| EP3150118A4 (en) * | 2014-05-30 | 2018-01-17 | Rafael Holzhacker | Module for detecting bodily signals |
Also Published As
| Publication number | Publication date |
|---|---|
| BRPI0801014A2 (en) | 2010-08-31 |
| BRPI0801014A8 (en) | 2015-09-29 |
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