Title of Invention	A METHOD OF HYSTERO ELECTRICAL ACTIVING MAPPING
Abstract	In this work, a method to record the multichannel Electro Hysterographic (EHG) signal and foetal electrocardiographic (FECG) signal non invasively and present the information in image form has been developed. Activities taking place in the entire uterus have been computed from the EHG signal acquired from 8 locations using the dedicated hardware and software by this method. Output is displayed as a colour coded image known as Hystero Electrical Activity Mapping (HEAM). Sequential display of HEAM patterns will provide clear information of functioning of uterus during labour. This method acquires FECG signals and extracts and enhances only FECG signals and displays Foetal Heart Rate (FHR) variability. Further, this method gives the FHR variability and the EHG signals in a single image.The method has immense application in the area of obstetrics.

Title of Invention

A METHOD OF HYSTERO ELECTRICAL ACTIVING MAPPING

Abstract

In this work, a method to record the multichannel Electro Hysterographic (EHG) signal and foetal electrocardiographic (FECG) signal non invasively and present the information in image form has been developed. Activities taking place in the entire uterus have been computed from the EHG signal acquired from 8 locations using the dedicated hardware and software by this method. Output is displayed as a colour coded image known as Hystero Electrical Activity Mapping (HEAM). Sequential display of HEAM patterns will provide clear information of functioning of uterus during labour. This method acquires FECG signals and extracts and enhances only FECG signals and displays Foetal Heart Rate (FHR) variability. Further, this method gives the FHR variability and the EHG signals in a single image.The method has immense application in the area of obstetrics.

Full Text	FIELD OF INVENTION : Biomedical Engineering BACKGROUND OF INVENTION : To develop a low cost non invasive device for monitoring of uterine and foetal electrical activities and presenting the information in a colour coded image by which the obstetrician can get diagnostic information easily. EXISTING EQUIPMENT For recording the uterine activity, either invasive technique or non invasive technique is applied. In the invasive method the pressure transducer is applied directly to the uterus and the uterine activity is recorded. In the non invasive technique the pressure transducer in a belt is to be tied around the abdomen of the patient and the pressure variations due to the uterine activity are recorded. For recording the foetal electro cardiographic signals, an ultrasonic Doppler transducer is applied and the foetal heart rate is calculated from the mechanical action of the foetal heart. Nowadays cardiotocograph(CTG) is an equipment being used to record uterine activity and foetal heart rate simultaneously. One of its two channels will record the uterine activity and the other channel records the foetal heart rate in a non invasive manner as discussed above. But the existing units have the following drawbacks. The invasive technique has the possibility of causing infection to the patient and the measurement can be done only if the membrane is ruptured. The above said non invasive technique of belt transducer for uterine activity has the drawbacks that if the belt is too tight, the measurement error will be there and the patient will feel much discomfort. If the belt is loosely wound, then the uterine activity will not measured properly. Above all, the measurement is limited to area under the transducer alone. The Doppler transducer technique of recording the foetal heart rate shows only the mechanical action of the heart and it does not give any information about the electrical activity of the foetal heart. But in the device presented here, both the uterine activity and the foetal electrocardiograhic signals are recorded either simultaneously or individually with entirely in a non invasive manner. The device uses only adhesive electrodes fixed on the abdomen and hence there is no possibility of causing any discomfort or infection to the patient. Since it is non invasive, the signals can be recorded from the onset of labour till delivery without any discomfort to the patient. Also the processed information by the device is given in a manner such that the obstetrician can get information about the progress of labour and about the foetal distress if any. BRIEF STATEMENT OF THE INVENTION The device being discussed here is applied to record uterine activity in the form of multichannel Electro Hysterographic (EHG) signal and the foetal electrocardiographic signals and presenting the information in a manner by which the obstetrician can get diagnostic information easily. The main advantage of the device is that it is entirely non invasive. S"HE OBJECTS OF THE INVENTION main object of the invention is to develop an acceptable device which will help the obstetrician to know the exact condition of the uterine activity taking place at different regions of uterus in different phases of delivery and also the condition of the foetus. BASIC PARTICULARS OF THE INVENTION The device has two parts in it namely the one which is acquiring, processing and displaying the Electro Hysterographic signal and the other to acquire foetal electrocardiographic signal, to process and to display the variation of foetal heart rate along with the uterine activity. In the device presented here, 8 electrode positions on the abdomen are selected to cover the activity of the entire uterus. From these locations, the electrical signal due to uterine contraction which is EHG signal is acquired simultaneously by 8 identical amplifier sections. The amplifiers are designed to have a gain of 3000 with the low pass filter having a pass band upto 1 GHz. These parameters are selected because the EHG potential is having an amplitude of 50 to 5 mV and frequency band of 0.03 to 2Hz. The signal can be acquired from patients till the last stage of pregnancy since the electrodes or the measurement system is totally noninvasive and will not cause any discomfort to the patient or to the obstetrician. The signal is then digitised by 8 bit analog to digital converter. After digitisation, these 8 channels of information are processed as below by the device to show the uterine activity in a manner acceptable to the obstetrician.. The level of the electrical signal on every point of the uterus is calculated from the information available on the 8 electrode locations, using 4 nearest neighbourhood method. These digital values thus calculated have been divided into 8 levels according to their magnitudes and each level has been assigned a specific colour. This colour coded information is displayed as an image on the monitor. This colour coded image of the EHG is named as Hysteric Electrical Activity Mapping (HEAM). Sequentially displaying these HEAM patterns at regular intervals of time will give a clear picture of uterine activity taking place during the entire process of labour. The colour pattern of the HEAM will indicate the direction of uterine muscle contraction. The recording can be done till delivery. The sequential HEAM pattern is shown in Sheet No. 1. In the HEAM pattern shown in Sheet Nol, the uterine contractile potential acquired by the 8 electrodes ( shown as 8 white dots in the HEAM pattern) on the abdomen is shown as a colour coded image giving indication about the uterine activity and the single column display on the right indicates the set of 8 colours and the pixel values corresponding to each of these colours. This will help the obstetrician to know the level of contraction taking place at every section of the uterus and the complete picture of the contractile activities over the entire uterus at the same time. The second part of the work deals with acquisition of foetal electrocardiographic (FECG) signal. In this work a pair of electrodes are fixed on the abdomen from which the FECG is picked up. Since this is non invasive, the recording can be carried over till the labour is over. The block diagram of the circuit to acquire FECG is given in Sheet No. 2. The FECG is picked up and preamplified using the first two stages of signal is passed through a band pass filter having pass band from 15 Hz to 35Hz to remove noise. This filtered signal is amplified by another set of two stages of amplifier. The total gain of the amplifiers is 10^. The salient aspect of the unit is that same pair of adhesive electrodes are used for picking up EHG and FECG. This FECG and the EHG potential are recorded simultaneously and digitized. The FECG signal is extracted food the background noise by wavelet transform technique and foetal heart rate (FHR) is calculated. Then the device generates a picture in which the EHG potential, the FHR and the extracted FECG are displayed as one frame as shown in Sheet No.3. In Sheet No. 3, the first waveform shows the EHG potential developed due to uterine activity, the second recording shows the variation of the foetal heart rate (FHR) and the last one shows the extracted and enhanced foetal electrocardiographic signal. From this the obstetrician can identify the variation of FHR as a response to uterine contraction. This is an integration of uterine activity and FHR variability. When both the displays are there, the presence of any compression on the foetus is indicated by the HEAM pattern and the corresponding FHR variability will be given by the other display. These two displays will indicate the obstetrician whether the foetus is in distress or not. We claim, 1. A method of invasive Hystero Electrical Activity Mapping Linear wherein the multichannel Electro Hysterographic signal ),%acquired , Electro Hysterographic signal recessed , colour coded image of Electro Hysterographic signal, produced, the foetal electrocardiographic signal non invasively acquired simultaneously with Electro Hysterographic signal, fontal electrocardiographic signal processed, foetal heart rate computed. Electro Hysterographic signal displayed along with foetal heart rate variability as one image. 2. A method as set forth in Claim 1, wherein non invasive indicates the use of adhesive electrodes on the abdomen, 3. A method as set forth in Claim 1, wherein Electro Hysterographic signal indicates the electrical signal produced by the uterine activity 4. A method as set forth in Claim 1, wherein the multichannel indicates the acquisition of Electro Hysterographic signal in a non invasive manner by adhesive electrodes. 5. A method as set forth in Claim 1, wherein the multi channel Electro Hysterographic signal acquired indicates that the Electro Hysterographic signal is acquired simultaneously from 8 different locations on the abdomen covering the entire uterus 6. A method as set forth in Claim I wherein the multi channel Electro Hysterographic signal acquired indicates that the Electro Hysterographic signal is acquired from identical amplifier systems with amplifiers, filters as 8 channels of Electro Hysterographic signals, 7. A method as set forth in Claim 1, wherein the multi channel Electro Hysterographic signal is processed indicates the Electro Hysterographic signal as acquired digitized. 8. A method as set forth in Claim 1, wherein the colour coded image of Electro Hysterographic signal is produced indicates that the digital values of Electro Hysterographic signal on every point of the uterus acquired are calculated by 4 nearest neighborhood method. 9. A method as set forth in Claim $^ wherein the colour coded image of Electro Hysterographic signal is produced indicates that the calculated digital values \|^-G4aifn-8^ are divided into 8 levels. ^ 10. A method as set forth in Claim 1, wherein the colour coded image of Electro Hysterographic signal is produced indicates that the 8 levels of Electro Hysterographic signal allotted 8 specific colors. 13. A method set forth in Claim 1, wherein the foetal electrocardiographic signal non invasively acquired simultaneously with Electro Hysterographic signal indicates that the foetal electrocardiographic signal along with Electro Hysterographic signal is acquired from the abdomen simultaneously from the same pair of electrodes 14. A method set forth in Claim 1, wherein the foetal electrocardiographic signal processed indicates that the foetal electrocardiographic signal is digitized, processed by wavelet transform technique to extract the foetal electrocardiographic alone. 15. A method set forth in Claim 1, wherein the foetal electrocardiographic signal processed indicates that from the foetal electrocardiographic signal extracted foetal heart rate variability is calculated. 16. A method set forth in Claim 1, wherein the Electro Hysterographic signal displayed along with foetal heart rate as one image indicates that the calculated foetal heart rate variability CilninT4y, is displayed with Electro Hysterographic signal as one image.

Full Text

FIELD OF INVENTION : Biomedical Engineering
BACKGROUND OF INVENTION :
To develop a low cost non invasive device for monitoring of uterine and foetal electrical activities and presenting the information in a colour coded image by which the obstetrician can get diagnostic information easily.
EXISTING EQUIPMENT
For recording the uterine activity, either invasive technique or non invasive technique is applied. In the invasive method the pressure transducer is applied directly to the uterus and the uterine activity is recorded. In the non invasive technique the pressure transducer in a belt is to be tied around the abdomen of the patient and the pressure variations due to the uterine activity are recorded. For recording the foetal electro cardiographic signals, an ultrasonic Doppler transducer is applied and the foetal heart rate is calculated from the mechanical action of the foetal heart.
Nowadays cardiotocograph(CTG) is an equipment being used to record uterine activity and foetal heart rate simultaneously. One of its two channels will record the uterine activity and the other channel records the foetal heart rate in a non invasive manner as discussed above.
But the existing units have the following drawbacks. The invasive technique has the possibility of causing infection to the patient and the measurement can be done only if the membrane is ruptured. The above said non invasive technique of belt transducer for uterine activity has the drawbacks that if the belt is too tight, the measurement error will be there and the patient will feel much discomfort. If the belt is loosely wound, then the uterine activity will not measured properly. Above all, the measurement is limited to area under the transducer alone.

The Doppler transducer technique of recording the foetal heart rate shows only the mechanical action of the heart and it does not give any information about the electrical activity of the foetal heart.
But in the device presented here, both the uterine activity and the foetal electrocardiograhic signals are recorded either simultaneously or individually with entirely in a non invasive manner. The device uses only adhesive electrodes fixed on the abdomen and hence there is no possibility of causing any discomfort or infection to the patient. Since it is non invasive, the signals can be recorded from the onset of labour till delivery without any discomfort to the patient. Also the processed information by the device is given in a manner such that the obstetrician can get information about the progress of labour and about the foetal distress if any.
BRIEF STATEMENT OF THE INVENTION
The device being discussed here is applied to record uterine activity in the form of multichannel Electro Hysterographic (EHG) signal and the foetal electrocardiographic signals and presenting the information in a manner by which the obstetrician can get diagnostic information easily.
The main advantage of the device is that it is entirely non invasive.
S"HE OBJECTS OF THE INVENTION
main object of the invention is to develop an acceptable device which will help the obstetrician to know the exact condition of the uterine activity taking place at different regions of uterus in different phases of delivery and also the condition of the foetus.
BASIC PARTICULARS OF THE INVENTION
The device has two parts in it namely the one which is acquiring, processing and displaying the Electro Hysterographic signal and the other to acquire foetal electrocardiographic signal, to process and to display the variation of foetal heart rate along with the uterine activity.

In the device presented here, 8 electrode positions on the abdomen are selected to cover the activity of the entire uterus. From these locations, the electrical signal due to uterine contraction which is EHG signal is acquired simultaneously by 8 identical amplifier sections. The amplifiers are designed to have a gain of 3000 with the low pass filter having a pass band upto 1 GHz. These parameters are selected because the EHG potential is having an amplitude of 50 to 5 mV and frequency band of 0.03 to 2Hz. The signal can be acquired from patients till the last stage of pregnancy since the electrodes or the measurement system is totally noninvasive and will not cause any discomfort to the patient or to the obstetrician. The signal is then digitised by 8 bit analog to digital converter. After digitisation, these 8 channels of information are processed as below by the device to show the uterine activity in a manner acceptable to the obstetrician.. The level of the electrical signal on every point of the uterus is calculated from the information available on the 8 electrode locations, using 4 nearest neighbourhood method. These digital values thus calculated have been divided into 8 levels according to their magnitudes and each level has been assigned a specific colour. This colour coded information is displayed as an image on the monitor. This colour coded image of the EHG is named as Hysteric Electrical Activity Mapping (HEAM). Sequentially displaying these HEAM patterns at regular intervals of time will give a clear picture of uterine activity taking place during the entire process of labour. The colour pattern of the HEAM will indicate the direction of uterine muscle contraction. The recording can be done till delivery. The sequential HEAM pattern is shown in Sheet No. 1. In the HEAM pattern shown in Sheet Nol, the uterine contractile potential acquired by the 8 electrodes ( shown as 8 white dots in the HEAM pattern) on the abdomen is shown as a colour coded image giving indication about the uterine activity and the single column display on the right indicates the set of 8 colours and the pixel values corresponding to each of these colours. This will help the obstetrician to know the level of contraction taking place at every section of the uterus and the complete picture of the contractile activities over the entire uterus at the same time.
The second part of the work deals with acquisition of foetal electrocardiographic (FECG) signal.

In this work a pair of electrodes are fixed on the abdomen from which the FECG is picked up. Since this is non invasive, the recording can be carried over till the labour is over. The block diagram of the circuit to acquire FECG is given in Sheet No. 2. The FECG is picked up and preamplified using the first two stages of signal is passed through a band pass filter having pass band from 15 Hz to 35Hz to remove noise. This filtered signal is amplified by another set of two stages of amplifier. The total gain of the amplifiers is 10^. The salient aspect of the unit is that same pair of adhesive electrodes are used for picking up EHG and FECG. This FECG and the EHG potential are recorded simultaneously and digitized. The FECG signal is extracted food the background noise by wavelet transform technique and foetal heart rate (FHR) is calculated. Then the device generates a picture in which the EHG potential, the FHR and the extracted FECG are displayed as one frame as shown in Sheet No.3. In Sheet No. 3, the first waveform shows the EHG potential developed due to uterine activity, the second recording shows the variation of the foetal heart rate (FHR) and the last one shows the extracted and enhanced foetal electrocardiographic signal. From this the obstetrician can identify the variation of FHR as a response to uterine contraction. This is an integration of uterine activity and FHR variability. When both the displays are there, the presence of any compression on the foetus is indicated by the HEAM pattern and the corresponding FHR variability will be given by the other display. These two displays will indicate the obstetrician whether the foetus is in distress or not.

We claim,
1. A method of invasive Hystero Electrical Activity Mapping Linear wherein the multichannel Electro Hysterographic signal ),%acquired , Electro Hysterographic signal recessed , colour coded image of Electro Hysterographic signal, produced, the foetal electrocardiographic signal non invasively acquired simultaneously with Electro Hysterographic signal, fontal electrocardiographic signal processed, foetal heart rate computed. Electro Hysterographic signal displayed along with foetal heart rate variability as one image.
2. A method as set forth in Claim 1, wherein non invasive indicates the use of adhesive electrodes on the abdomen,
3. A method as set forth in Claim 1, wherein Electro Hysterographic signal indicates the electrical signal produced by the uterine activity
4. A method as set forth in Claim 1, wherein the multichannel indicates the acquisition of Electro Hysterographic signal in a non invasive manner by adhesive electrodes.
5. A method as set forth in Claim 1, wherein the multi channel Electro Hysterographic signal acquired indicates that the Electro Hysterographic signal is acquired simultaneously from 8 different locations on the abdomen covering the entire uterus
6. A method as set forth in Claim I wherein the multi channel Electro Hysterographic signal acquired indicates that the Electro Hysterographic signal is acquired from identical amplifier systems with amplifiers, filters as 8 channels of Electro Hysterographic signals,
7. A method as set forth in Claim 1, wherein the multi channel Electro Hysterographic signal is processed indicates the Electro Hysterographic signal as acquired digitized.

8. A method as set forth in Claim 1, wherein the colour coded image of Electro Hysterographic signal is produced indicates that the digital values of Electro Hysterographic signal on every point of the uterus acquired are calculated by 4 nearest neighborhood method.
9. A method as set forth in Claim $^ wherein the colour coded image of Electro Hysterographic signal is produced indicates that the calculated digital values |^-G4aifn-8^ are divided into 8 levels. ^
10. A method as set forth in Claim 1, wherein the colour coded image of Electro
Hysterographic signal is produced indicates that the 8 levels of Electro Hysterographic
signal allotted 8 specific colors.

13. A method set forth in Claim 1, wherein the foetal electrocardiographic signal non
invasively acquired simultaneously with Electro Hysterographic signal indicates that the
foetal electrocardiographic signal along with Electro Hysterographic signal is acquired
from the abdomen simultaneously from the same pair of electrodes
14. A method set forth in Claim 1, wherein the foetal electrocardiographic signal
processed indicates that the foetal electrocardiographic signal is digitized, processed by
wavelet transform technique to extract the foetal electrocardiographic alone.
15. A method set forth in Claim 1, wherein the foetal electrocardiographic signal
processed indicates that from the foetal electrocardiographic signal extracted foetal heart rate variability is calculated.
16. A method set forth in Claim 1, wherein the Electro Hysterographic signal displayed
along with foetal heart rate as one image indicates that the calculated foetal heart rate
variability CilninT4y, is displayed with Electro Hysterographic signal as one image.

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Patent Number

200703

Indian Patent Application Number

60/MAS/2001

PG Journal Number

8/2007

Publication Date

23-Feb-2007

Grant Date

30-May-2006

Date of Filing

23-Jan-2001

Name of Patentee

DR. G. RAVINDRAN

Applicant Address

DIRECTOR, CENTRE FOR MEDICAL ELECTRONICS, ANNA UNIVERSITY, GUINDY, CHENNAI 600 025

Inventors:

#	Inventor's Name	Inventor's Address
1	DR. G. RAVINDRAN	DIRECTOR, CENTRE FOR MEDICAL ELECTRONICS, ANNA UNIVERSITY, GUINDY, CHENNAI 600 025
2	MIS. S. SHENBAGA DEVI	LECTURER(SENIOR), CENTRE FOR MEDICAL ELECTRONICS, ANNA UNIVERSITY, GUINDY, CHENNAI 600 025

PCT International Classification Number

A61B 5/044

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA