Calculation method of uterine contraction consistency based on uterine myoelectric signals

Abstract

A method for calculating uterine contraction consistency based on uterine myoelectric signals, comprising: step S1, collecting multi-channel uterine myoelectric signals and converting them into digital signals; step S2, band-pass filtering the uterine myoelectric signals to remove interference noise; step S3, confirming the uterine contraction position according to TOCO or uterine contraction detection algorithm, and intercepting the EHG uterine contraction segment according to the start and end time of the uterine contraction. Step S4, for multi-channel EHG uterine contraction segments, calculating the Pearson correlation coefficient COR of each channel to form a connectivity matrix; step S5, treating the connectivity matrix as an adjacency matrix in graph theory, setting a threshold T, and setting it to 0 when the value in the adjacency matrix is ​​less than the threshold, otherwise setting it to 1, thereby establishing an association between different electrode nodes. Step S6, calculating the local efficiency E of each electrode node i The consistency E of the entire uterine contraction is calculated based on the local efficiency, thereby characterizing the degree to which the pregnant woman is close to delivery.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological signal processing, and in particular relates to a method for calculating uterine contraction consistency based on uterine myoelectric signals. Background Art

[0002] Premature birth (delivery before 37 weeks of gestation) is the main risk of pregnancy for both mother and baby. If a baby is born prematurely, he or she may suffer serious complications or even die.

[0003] Obstetricians generally determine whether a pregnant woman is experiencing premature birth by analyzing the degree of her uterine contractions. The commonly used uterine contraction detection device in clinical practice is the tocograph (TOCO), which indirectly analyzes the presence of uterine contractions by measuring the pressure exerted by uterine contractions on the abdominal wall. However, the TOCO cannot analyze the consistency of uterine contractions, which is closely related to premature birth: uterine contractions in early and mid-pregnancy are usually localized and disordered, while during labor, uterine contractions usually start from the top two uterine horns and spread to the midline of the uterine fundus, symmetrically on both sides, and then spread to the lower uterine segment at a speed of about 2 cm / s. After about 15 seconds, they evenly and harmoniously spread throughout the entire uterus.

[0004] The relationship between uterine contractions and action potentials in uterine muscle cells offers new insights into characterizing uterine contractions. These action potentials can be measured using electrodes placed on the patient's abdomen to generate uterine electromyogram (EHG). Using multiple electrodes to collect EHG signals from different locations on the abdomen creates a multi-channel EHG signal, and characterizing the consistency of uterine contractions is crucial for diagnosing premature birth. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art and provide a method for characterizing uterine contraction consistency based on uterine myoelectric signals to determine whether uterine contractions are close to the onset of labor. The specific steps implemented by the present invention to solve the technical problem are as follows:

[0006] Step S1, collecting multi-channel uterine electromyographic signals and converting them into digital signals;

[0007] Step S2, performing bandpass filtering on the uterine myoelectric signal to remove interference noise;

[0008] Step S3: Confirm the uterine contraction position according to TOCO or the uterine contraction detection algorithm, and intercept the EHG uterine contraction segment according to the start and end time of the uterine contraction.

[0009] Step S4: for the multi-channel EHG uterine contraction segment, calculate the Pearson correlation coefficient COR of each channel to form a connectivity matrix;

[0010] Step S5: The connectivity matrix is ​​regarded as an adjacency matrix in graph theory, and a threshold T is set. When the value in the adjacency matrix is ​​less than the threshold, it is set to 0, otherwise it is set to 1, thereby establishing the association between different electrode nodes.

[0011] Step S6: Calculate the local efficiency E of each electrode node i The consistency E of the entire uterine contraction is calculated based on the local efficiency, thereby characterizing the degree to which the pregnant woman is close to delivery.

[0012] The benefit of the present invention lies in that it depicts the consistency of uterine contractions based on uterine myoelectric signals, analyzes the degree of labor of pregnant women according to the degree of consistency, and provides a reference for doctors to analyze whether pregnant women will have premature birth. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Flowchart of the present invention.

[0014] Figure 2a-2c This is an example of establishing a graph network based on the adjacency matrix of the present invention, where Figure 2a It is a 16-channel uterine myoelectric signal collected. Figure 2b is the connectivity matrix established by calculating the Pearson correlation coefficient between channels, Figure 2c It is a graph network formed based on the connectivity matrix.

[0015] Figure 3 This is an example of the electrode positions for collecting 16-channel uterine myoelectric signals in the present invention. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0018] The technical solution of the present invention will be described below with reference to the accompanying drawings.

[0019] The specific steps implemented by the present invention to solve the technical problem are as follows:

[0020] Step S1: Figure 3 As shown, uterine myoelectric signals are collected through 16 electrodes and converted into digital signals;

[0021] Step S2, performing a 0.1 to 3 Hz bandpass filter on the uterine myoelectric signal to remove interference noise;

[0022] Step S3: confirm all uterine contraction positions according to TOCO or uterine contraction detection algorithm, and intercept EHG uterine contraction segments according to the start and end times of the uterine contraction.

[0023] Step S4: for the multi-channel EHG uterine contraction segment, calculate the Pearson correlation coefficient COR of each channel to form a connectivity matrix;

[0024] Step S5: Treat the connectivity matrix as an adjacency matrix. Its network topology can be analyzed using graph theory. A threshold, T, is set. When the value in the adjacency matrix is ​​less than the threshold, it is set to 0; otherwise, it is set to 1. This establishes the association between different electrode nodes. T is empirically set to 0.8.

[0025] Step S6: Calculate the local efficiency E of each electrode node i The consistency E of the entire uterine contraction is calculated based on the local efficiency, thereby characterizing the degree to which the pregnant woman is close to delivery.

[0026] The above step S4 specifically includes: calculating the Pearson correlation coefficient between each channel, and the calculation method is as follows:

[0027]

[0028] Where L is the length of the contraction segment, and are the mean of the signal segments of channels x and y, respectively. The COR values ​​between all channels form the connectivity matrix.

[0029] The above step S6 specifically includes: calculating the local efficiency of each electrode node, and the calculation formula is as follows:

[0030]

[0031] Where n is the number of nodes, S is the set of all nodes in the graph, and d ij is the shortest distance between nodes i and j, which is calculated as follows:

[0032]

[0033] When nodes i and j are connected, a uv =1, otherwise 0. Represents the shortest path between i and j in the graph network.

[0034] E i The value range is [0,1]. When there is a connecting edge between each vertex, E iReach the maximum value. According to the local efficiency E of each node i The global efficiency of uterine contraction is obtained, which is regarded as the consistency of the entire uterine contraction. The calculation formula is as follows:

[0035]

[0036] The value range of uterine contraction consistency E is [0,1], and the closer the pregnant woman is to delivery, the higher the value.

[0037] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0038] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for analyzing uterine contraction consistency based on uterine myoelectric signals, comprising the following steps: Step S1, collecting multi-channel uterine electromyographic signals and converting them into digital signals; Step S2, performing bandpass filtering on the uterine myoelectric signal to remove interference noise; Step S3: confirm the location of the uterine contraction according to the TOCO or uterine contraction detection algorithm, and intercept the EHG uterine contraction segment according to the start and end time of the uterine contraction; Step S4: for the multi-channel EHG uterine contraction segment, calculate the Pearson correlation coefficient COR of each channel to form a connectivity matrix; Step S5: The connectivity matrix is ​​regarded as an adjacency matrix in graph theory, and a threshold T is set. When the value in the adjacency matrix is ​​less than the threshold, it is set to 0, otherwise it is set to 1, thereby establishing the association between different electrode nodes; Step S6: Calculate the local efficiency E of each electrode node i ; and calculate the consistency E of the entire uterine contraction based on the local efficiency, thereby characterizing the degree to which the pregnant woman is close to delivery; specifically, it includes: calculating the local efficiency of each electrode node, and the calculation formula is as follows: Where n is the number of nodes, S is the set of all nodes in the graph, and d ij is the shortest distance between nodes i and j, which is calculated as follows: When nodes i and j are connected, a uv =1, otherwise 0; Represents the shortest path between i and j in the graph network; E i The value range is [0,1]. When there is a connecting edge between each vertex, E i Reach the maximum value; according to the local efficiency E of each node i The global efficiency of uterine contraction is obtained, which is regarded as the consistency of the entire uterine contraction. The calculation formula is as follows: The value range of uterine contraction consistency E is [0,1], and the closer the pregnant woman is to delivery, the higher the value.

2. The method for analyzing uterine contraction consistency based on uterine myoelectric signals according to claim 1, wherein step S4 specifically comprises: Calculate the Pearson correlation coefficient between each channel as follows: Where L is the length of the contraction segment, and are the means of the signal segments of channels x and y, respectively; the COR values ​​between all channels form the connectivity matrix.

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