WO2003055395A1 - Analysis of acoustic medical signals - Google Patents
Analysis of acoustic medical signals Download PDFInfo
- Publication number
- WO2003055395A1 WO2003055395A1 PCT/GB2002/005922 GB0205922W WO03055395A1 WO 2003055395 A1 WO2003055395 A1 WO 2003055395A1 GB 0205922 W GB0205922 W GB 0205922W WO 03055395 A1 WO03055395 A1 WO 03055395A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- signal
- wavelet
- respiration
- wavelet transform
- pulse
- Prior art date
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Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B7/00—Instruments for auscultation
- A61B7/02—Stethoscopes
- A61B7/04—Electric stethoscopes
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B7/00—Instruments for auscultation
- A61B7/003—Detecting lung or respiration noise
Definitions
- the present invention relates to a method of analysis of medical signals, and in particular to a method of decomposition and analysis of signals used in phonocardiography. Specifically the invention relates to an improved method of denoising acoustic cardiac signals and in the extraction of clinically useful information from such signals including the location of relevant cardiac sounds in the signal and the monitoring and analysis of patient respiration including the determination of breathing rate.
- the denoising of acoustic cardiac signals is essential in order to facilitate their clinical evaluation.
- the removal of noise including movement artefact is the main goal of current signal analysis methods.
- Our method allows for clinically relevant information to be extracted from acoustic cardiac waveforms even when a high level of noise is present in the signal .
- Wavelet transforms allow a signal to be decomposed such that both the frequency characteristics and the temporal location of particular features in a time series may be highlighted simultaneously.
- This feature localisation property overcomes the basic shortcoming of Fourier analysis, where the spectrum only contains globally averaged information which leads to location specific features in the signal being lost.
- STFT short time Fourier transform
- the wavelet-based method cannot resolve to an arbitrarily small scale due to the variable window width associated with the wavelet function.
- the wavelet transform of a continuous time signal, x (t) is defined as:
- a is the wavelet scale parameter
- b is the wavelet location parameter
- g (t) is the analysing wavelet function
- g * (t) its complex conjugate.
- the present invention provides a method of measuring physiological parameters, comprising processing a phonocardiogram signal using wavelet transform methods; and also provides a system suitable for carrying out the method.
- the invention is a wavelet transform-based method for the elucidation of pertinent features from noisy acoustic cardiac waveforms associated with both cardiac and respiratory activity.
- These techniques will be used within phonocardiographic signal acquisition and analysis devices (including remote devices used, for example, to monitor neonates) to monitor cardiac or respiratory activity, and preferably both, and provide information concerning these activities including pulse rate and respiration rate.
- the methodology can facilitate the clinical interpretation of acoustic cardiac waveforms which suffer from excessive noise, including noise from movement artefact and poor coupling between microphone and patient. Poor coupling may arise from the lack of a rigid connection of the microphone and the patient skin or the placement of the microphone within the patient clothes. This document describes the methodology and its incorporation within a medical device.
- Figure 2 (a) Wavelet Analysis of an Acoustic Cardiac Signal - Original Acoustic Cardiac Waveform.
- Figure 2 (b) Wavelet Analysis of an Acoustic Cardiac Signal - the Wavelet Scalogram Corresponding to the signal in figure 2 (a)
- Figure 2 (c) Wavelet Analysis of an Acoustic Cardiac Signal - The scalogram values from the selected band-pass centre frequency of the wavelet showing alternate large and small amplitude maxima (marked a and b in the figure) .
- Figure 3 A detailed block diagram of a preferred embodiment of the wavelet-based pulse rate determination.
- Figure 4 (b) Wavelet Transform Phase Plot corresponding to the Signal in Figure 4 (a)
- Figure 5 (a) Wavelet Transform Modulus Plot of the signal shown in Figure 4 (a) .
- Figure 5 (b) Wavelet Transform Modulus Plot of the signal in Figure 4 (a) with possible routes of pulse and breathing ridges shown schematically.
- Figure 6 A detailed block diagram of a preferred embodiment of the wavelet-based respiration and pulse rate determination.
- Figure 1 shows an artefact free acoustic cardiac waveform.
- the two adjacent wavetrain pulses corresponding to a single heartbeat (Si and S 2 sounds) are evident in the middle of the plot.
- the time trace in Figure 2 (a) contains an acoustic cardiac waveform collected from a young baby where very poor coupling between the microphone and patient was present. As well as this poor coupling, the signal suffers from breathing and movement artefact, signal drop-outs and undersampling. (The difference in the quality from the trace in figure 1 is obvious.)
- the wavelet scalogram derived from the signal in Figure 2(a) is shown in Figure 2b.
- the bottom trace ( Figure 2 (c) ) contains the wavelet transform values across the scalogram corresponding to a selected band-pass frequency centre of the wavelet.
- Figure 3 contains a block diagram of a preferred embodiment of the pulse detection and rate determination algorithm as incorporated within a medical device.
- the digitised acoustic cardiac signal 10 is sent to a wavelet transformer 11.
- a frequency level 12 is selected in wavelet space - either automatically or, as in this case, manually.
- the wavelet transform values across this level are interrogated 13 and the occurrence of the alternate large and small peaks ( Figure 2(c)) used to determine the pulse frequency.
- Figure 4 (a) contains a longer segment of the signal shown in Figure 2.
- Figure 4(b) the wavelet transform phase is plotted, derived using a complex wavelet analysing function. At this resolution, new, regular structure can be observed at frequencies at, around, and below 1Hz . This corresponds to patient breathing.
- Figure 5(a) contains a three dimensional, modulus plot of the (wavelet) transformed signal of Figure 4(a). Two ridges appear in the transform surface of Figure 5 (a) corresponding to the breathing and pulse signals. The pulse and breathing rate can be obtained directly from these ridges in the time frequency plane .
- Figure 5 (b) shows the same scalogram as Figure 5 (a) .
- a schematic of the loci of the breathing and respiration ridges is plotted as black broken lines above the wavelet transform surface.
- the breathing and respiration ridges may be tracked across the wavelet transform surface using a suitable ridge following algorithm as is currently available. Using both phase and modulus information both breathing and pulse signals can be monitored to provide the clinically useful information (e.g. the breathing and/or pulse rate, significant changes in breathing and/or pulse pattern, etc.) hidden within signals containing high degrees of noise and artefact .
- FIG. 6 contains a block diagram of a preferred embodiment of the pulse and respiration detection and rate determination algorithm.
- the digitised acoustic cardiac signal 20 is sent to a wavelet transformer 21.
- a representation of the transform is made in the time frequency domain as a surface 22. This can be, for example, the scalogram or rescaled scalogram as described above.
- the dominant ridges associated with the manifestation of respiration in the signal are determined 23. This is used to provide a respiration frequency through time directly from the time-frequency representation 24.
- the dominant ridges associated with the manifestation of pulse in the signal may also be determined 25. This is used to provide a pulse frequency through time directly from the time- frequency representation 26. This may also be used as a check of the pulse rate determination described above and in Figure 3.
- the resulting breathing rate and pulse rate may then be displayed on the device.
- the method may be similarly employed to analyse other acoustic medical signals and so determine pertinent clinical information.
- the method may be further employed to detect and identify motion artefact within signals of medical relevance.
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2002356324A AU2002356324A1 (en) | 2001-12-28 | 2002-12-24 | Analysis of acoustic medical signals |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0131024A GB0131024D0 (en) | 2001-12-28 | 2001-12-28 | Analysis of acoustic medical signals |
GB0131024.2 | 2001-12-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2003055395A1 true WO2003055395A1 (en) | 2003-07-10 |
Family
ID=9928445
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB2002/005922 WO2003055395A1 (en) | 2001-12-28 | 2002-12-24 | Analysis of acoustic medical signals |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU2002356324A1 (en) |
GB (1) | GB0131024D0 (en) |
WO (1) | WO2003055395A1 (en) |
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Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4289141A (en) * | 1976-08-19 | 1981-09-15 | Cormier Cardiac Systems, Inc. | Method and apparatus for extracting systolic valvular events from heart sounds |
WO1996008992A2 (en) * | 1994-09-14 | 1996-03-28 | Ramot University Authority For Applied Research & Industrial Development Ltd. | Apparatus and method for time dependent power spectrum analysis of physiological signals |
US5590650A (en) * | 1994-11-16 | 1997-01-07 | Raven, Inc. | Non-invasive medical monitor system |
US5957866A (en) * | 1995-07-03 | 1999-09-28 | University Technology Corporation | Apparatus and methods for analyzing body sounds |
WO2001062152A1 (en) * | 2000-02-23 | 2001-08-30 | The Johns Hopkins University | System and method for diagnosing pathologic heart conditions |
WO2001082099A1 (en) * | 1999-05-01 | 2001-11-01 | The Court Of Napier University | Method of analysis of medical signals |
-
2001
- 2001-12-28 GB GB0131024A patent/GB0131024D0/en not_active Ceased
-
2002
- 2002-12-24 AU AU2002356324A patent/AU2002356324A1/en not_active Abandoned
- 2002-12-24 WO PCT/GB2002/005922 patent/WO2003055395A1/en not_active Application Discontinuation
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4289141A (en) * | 1976-08-19 | 1981-09-15 | Cormier Cardiac Systems, Inc. | Method and apparatus for extracting systolic valvular events from heart sounds |
WO1996008992A2 (en) * | 1994-09-14 | 1996-03-28 | Ramot University Authority For Applied Research & Industrial Development Ltd. | Apparatus and method for time dependent power spectrum analysis of physiological signals |
US5590650A (en) * | 1994-11-16 | 1997-01-07 | Raven, Inc. | Non-invasive medical monitor system |
US5957866A (en) * | 1995-07-03 | 1999-09-28 | University Technology Corporation | Apparatus and methods for analyzing body sounds |
WO2001082099A1 (en) * | 1999-05-01 | 2001-11-01 | The Court Of Napier University | Method of analysis of medical signals |
WO2001062152A1 (en) * | 2000-02-23 | 2001-08-30 | The Johns Hopkins University | System and method for diagnosing pathologic heart conditions |
Non-Patent Citations (2)
Title |
---|
J ET AL: "A wavelet-based reduction of heart sound noise from lung sounds", INTERNATIONAL JOURNAL OF MEDICAL INFORMATICS, ELSEVIER SCIENTIFIC PUBLISHERS, SHANNON, IR, vol. 52, no. 1-3, 1 October 1998 (1998-10-01), pages 183 - 190, XP004153683, ISSN: 1386-5056 * |
SARKADY A A ET AL: "COMPUTER ANALYSIS TECHNIQUES FOR PHONOCARDIOGRAM DIAGNOSIS", COMPUTERS AND BIOMEDICAL RESEARCH, ACADEMIC PRESS, LONDON, GB, vol. 9, August 1976 (1976-08-01), pages 349 - 363, XP008005662, ISSN: 0010-4809 * |
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US9974468B2 (en) | 2013-03-15 | 2018-05-22 | Covidien Lp | Systems and methods for identifying a medically monitored patient |
US10022068B2 (en) | 2013-10-28 | 2018-07-17 | Covidien Lp | Systems and methods for detecting held breath events |
US9848820B2 (en) | 2014-01-07 | 2017-12-26 | Covidien Lp | Apnea analysis system and method |
US9955894B2 (en) | 2014-01-28 | 2018-05-01 | Covidien Lp | Non-stationary feature relationship parameters for awareness monitoring |
US10786198B2 (en) | 2014-01-28 | 2020-09-29 | Covidien Lp | Non-stationary feature relationship parameters for awareness monitoring |
US9901308B2 (en) | 2014-02-20 | 2018-02-27 | Covidien Lp | Systems and methods for filtering autocorrelation peaks and detecting harmonics |
US10537289B2 (en) | 2014-02-20 | 2020-01-21 | Covidien Lp | Systems and methods for filtering autocorrelation peaks and detecting harmonics |
US11284827B2 (en) | 2017-10-21 | 2022-03-29 | Ausculsciences, Inc. | Medical decision support system |
CN109567856A (en) * | 2018-11-23 | 2019-04-05 | 四川长虹电器股份有限公司 | A kind of auscultation position intelligent prompt method based on intelligent platform |
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AU2002356324A1 (en) | 2003-07-15 |
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