A method for eliminating respiratory interference in catheter position detection during three-dimensional model reconstruction

Abstract

A method for eliminating respiratory interference in catheter position detection in three-dimensional model reconstruction includes: receiving position data of an electrode or a magnetic pole on a target catheter; receiving position data of a reference electrode or a magnetic pole; extracting the amplitude and periodic phase of respiratory interference from the reference electrode or the magnetic pole; extracting the amplitude and periodic phase of respiratory interference from the target catheter electrode or the magnetic pole, and comparing them with a legal threshold; calculating the ratio and reference difference of respiratory disturbance data detected by the reference electrode or the magnetic pole and the target catheter electrode or the magnetic pole, and removing the reference difference at the same time; fitting the reference electrode or the magnetic pole position data with an equation, calculating the parameters of the influence of respiratory disturbance on the spatial position coordinates; using the reference electrode or the magnetic pole fitting to obtain the parameters to perform interference elimination calculation on the three-dimensional spatial position of the catheter electrode or the magnetic pole, and obtaining the final catheter position data. The present invention improves the accuracy and stability of the relative position of the catheter.

Description

Technical Field

[0001] The invention relates to the field of electrosurgery, and in particular to a method for eliminating respiratory interference in catheter position detection in three-dimensional model reconstruction. Background Art

[0002] In the field of electrosurgery, the catheter carries one or more electrodes or magnetic poles, which can be used for cardiac three-dimensional image reconstruction, catheter position display, etc., and cardiac three-dimensional reconstruction and catheter position display are important tools. Accurate cardiac models and catheter navigation are highly intuitive, and can determine the electrophysiological position information and scar tissue in the heart, etc., which is convenient for the surgeon to ablate the lesions of arrhythmias, avoid risky positions during surgery, or accurately evaluate the ablation process. By detecting the external field strength and its changes on the electrodes or magnetic pole sensors on the catheter, the position and direction of the catheter in the heart cavity can be determined, thereby further determining the three-dimensional structure of the heart cavity and displaying the real-time position information of the catheter in the endocardium of the heart cavity. However, breathing, as a dynamic physiological process, will continuously affect the spatial distribution of organs in the body, and may bring changes to the distribution of the external field, thereby affecting the position detection results of the catheter in the heart cavity, so that even if the relative position of the catheter in the heart cavity is stationary, the detected spatial position of the catheter is always changing. Therefore, the three-dimensional reconstruction of the heart cavity based on the catheter position is always disturbed by the patient's breathing, which may reduce the accuracy of the catheter position.

[0003] In the existing disclosed technologies, some adopt the method of collecting respiratory signals for a period of time in advance, and establish a model of the influence of respiratory amplitude and phase on the movement of the catheter, and use it as a basis in the subsequent operation process to decompose the detected catheter movement into two parts: the movement of the catheter itself and the respiratory interference. This method assumes that the influence of the respiratory signal on the movement of the catheter is consistent in the previous and subsequent processes, and the movement of the catheter itself needs to have strong continuity. However, in actual situations, it is difficult to collect the data of the respiratory signal on the movement of the catheter in various situations in advance to fully model the respiratory model. In addition, the rate of change of the catheter movement itself has certain mutation factors, and the amplitude and phase of the breathing are also affected by many irregular sudden situations. In addition, there are also some existing systems that directly eliminate the corresponding influence of the preset or previous measurement ratio from the catheter movement trajectory by measuring the phase of breathing. However, when the catheter movement speed is fast, it is difficult to continuously measure the influence of the respiratory signal on the catheter movement. In this case, directly deducting the respiratory component of the estimated ratio from the catheter movement sometimes causes overcompensation or amplification of the effect of respiratory influence. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a method for eliminating respiratory interference in catheter position detection during three-dimensional model reconstruction.

[0005] A method for detecting the position of a catheter in three-dimensional model reconstruction comprises:

[0006] S1, receiving position data of electrodes or magnetic poles on a target catheter;

[0007] S2, receiving position data of a reference electrode or a magnetic pole;

[0008] S3, extracting the respiratory interference amplitude and cycle phase from the reference electrode or magnetic pole;

[0009] S4, extracting the amplitude and cycle phase of respiratory disturbances from the target catheter electrode or magnetic pole and comparing them with legal thresholds;

[0010] S5, calculating the ratio and baseline difference of the respiratory disturbance data detected by the reference electrode or magnetic pole and the target catheter electrode or magnetic pole, and removing the baseline difference at the same time;

[0011] S6. Fitting the reference electrode or magnetic pole position data with an equation to calculate the parameters of the effect of respiratory disturbance on the spatial position coordinates;

[0012] S7, performing interference elimination calculation on the three-dimensional spatial position of the catheter electrode or magnetic pole using the parameters obtained by fitting the reference electrode or magnetic pole;

[0013] S8. Extract the spatial interference value that conforms to the law of previous respiratory cycles from the processed target catheter position data, and make a comprehensive judgment with the legal threshold to obtain the final catheter position data.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention effectively reduces the three-dimensional modeling deviation caused by respiratory disturbance, greatly improving the accuracy and stability of the real-time relative position of the catheter. By eliminating the interference of breathing on the real-time position detection result of the catheter in a multi-level progressive manner, it not only achieves the processing of different interference amplitudes between the reference magnetic pole or electrode and the catheter due to breathing, but also avoids the problem of inadequate position or unreasonable position distribution space caused by underfitting or overfitting, and detects the catheter position detection data and the three-dimensional space coordinate data in the final space coordinate system respectively.

[0016] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments: BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of a method for eliminating respiratory interference in catheter position detection in three-dimensional model reconstruction of the present invention;

[0018] Figure 2 A diagram showing the spatial variation of the reference electrode or magnetic pole and catheter position affected by respiratory disturbance;

[0019] Figure 3 A system diagram used in an embodiment of the present invention;

[0020] Figure 4 A diagram of a three-dimensional heart model constructed according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The embodiments of the technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and the protection scope of the present invention cannot be limited thereto. It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should be the common meanings understood by those skilled in the art to which the present invention belongs.

[0022] like Figure 1 As shown, a method for eliminating respiratory interference in catheter position detection in three-dimensional model reconstruction in this embodiment includes:

[0023] S1, receiving position data of electrodes or magnetic poles on a target catheter;

[0024] S2, receiving position data of a reference electrode or a magnetic pole;

[0025] S3, extracting the respiratory interference amplitude and cycle phase from the reference electrode or magnetic pole;

[0026] S4, extracting the amplitude and cycle phase of respiratory disturbances from the target catheter electrode or magnetic pole and comparing them with legal thresholds;

[0027] S5, calculating the ratio and baseline difference of the respiratory disturbance data detected by the reference electrode or magnetic pole and the target catheter electrode or magnetic pole, and removing the baseline difference at the same time;

[0028] S6. Fitting the reference electrode or magnetic pole position data with an equation to calculate the parameters of the effect of respiratory disturbance on the spatial position coordinates;

[0029] S7, performing interference elimination calculation on the three-dimensional spatial position of the catheter electrode or magnetic pole using the parameters obtained by fitting the reference electrode or magnetic pole;

[0030] S8. Extract the spatial interference value that conforms to the law of previous respiratory cycles from the processed target catheter position data, and make a comprehensive judgment with the legal threshold to obtain the final catheter position data.

[0031] In step S1 and step S2, the information acquisition device receives data of electrodes or magnetic poles on the target catheter to obtain the position data of the catheter in space. This data can be obtained by appropriate calculation means, such as by measuring and analyzing the electric field or magnetic field strength. In S2, the position data of reference electrodes or magnetic poles whose relative positions to the patient's heart chamber remain unchanged are received and detected, and these reference electrodes or magnetic poles are located at an external position.

[0032] In step S3, the interference amplitude and period of the reference electrode or magnetic pole position data due to breathing are determined and evaluated through relevant algorithms. For example, the amplitude and period of the interference introduced by breathing can be determined by analyzing and extracting using mathematical methods such as fast Fourier transform (FFT).

[0033] In step S5, the position change value introduced by the respiratory disturbance of the reference electrode or magnetic pole detected each time and the position change value introduced by the respiratory disturbance obtained by the preliminary prediction of the target catheter fitting calculation are calculated continuously to determine the multiple and difference between the two. The position deviation introduced by the respiratory disturbance of the target catheter calculated by the reference electrode or magnetic pole and the difference between the two is adjusted on the target catheter position data, so that the influence amplitude of the respiratory disturbance in the target catheter position data is reduced.

[0034] In step S6, parameter fitting is performed on the reference electrode or magnetic pole position change information detected in multiple respiratory cycles. The purpose of fitting is to ensure that the same parameter function is used to calculate the position change amplitude of the reference electrode or magnetic pole under different respiratory phases, so as to obtain as consistent spatial coordinate data as possible. The calculated parameters obtained by fitting are used as the influence coefficient of the data disturbance detected by the electrode or magnetic pole sensor on the reference electrode or magnetic pole and the target catheter on its spatial position.

[0035] In step S7, the respiratory disturbance amplitude of the target catheter obtained in step 5 and the fitting parameters obtained in step 6 are substituted into the position calculation function in step 6 to calculate the motion trajectory data of the target catheter. Thus, the respiratory signal disturbance component is deducted from the motion trajectory data of the target catheter to obtain the catheter space coordinate data after the removal.

[0036] In step 8, the continuous position data of the target catheter obtained in step 7 is filtered with the amplitude of synchronous change with the respiratory cycle to extract the target catheter position disturbance data. Then the extracted catheter position disturbance data is judged for rationality, and a mutation detection is performed with the disturbance data determined to be valid in the previous cycle to ensure the validity of the data, determine the amplitude of the remaining respiratory interference, and obtain the final catheter position data. After the above processing, the influence of respiratory interference on the data is eliminated to the greatest extent, the position data of the target catheter is more accurate, and can more accurately reflect the movement trajectory of the catheter.

[0037] The detected catheter and reference magnetic pole and electrode position data are continuously calculated in real time. The above steps S1 to S8 are repeated continuously. Each calculation result refers to the previous calculation result (filtering and mutation detection) and provides a benchmark for the next calculation, thereby eliminating the interference of breathing on the real-time position of the catheter.

[0038] In the above implementation scheme, in step 4, it is first determined whether the position of the catheter undergoes a large mutation, and the catheter disturbance amplitude is extracted when the change speed and amplitude are relatively stable. Otherwise, a reasonable estimation should be made based on the existing change amplitude and reference respiratory phase.

[0039] In step 8, it is first determined whether the position of the catheter has undergone a large mutation. When the change speed and amplitude are relatively stable, the catheter disturbance amplitude is extracted. Otherwise, a reasonable estimation should be made based on the existing change amplitude and reference respiratory phase.

[0040] The fitting function of the equation fitting in step 6 is a first-order or multi-order polynomial or a B-spline function.

[0041] The present invention will be further described below with examples:

[0042] The positioning data of the target catheter electrode or magnetic pole and the reference electrode or magnetic pole received in step 1 and step 2 are represented by X and X0, respectively. The amplitude and period of the respiratory disturbance of the reference electrode or magnetic pole in step S3 and step S4 are represented by Xa0 and T, respectively. The target catheter position data and the respiratory disturbance amplitude are compared with the legal threshold value, so that the amplitude of the respiratory disturbance received by the target catheter does not exceed the predefined threshold value, and the amplitude of the respiratory disturbance of the target catheter position is obtained as X a .

[0043] The calculation process of step 5 is: Xa0 = Xa 01 +Xa 02 , X a =c*Xa 01 +Xa 02 , according to the continuous calculation and fitting, Xa 02 The value is between 0.6 and 0.8 times of Xa0, and Xa is removed from the position data of the reference magnetic pole or electrode and the target catheter magnetic pole or electrode. 02 , but retain the same 01 The relevant interference amplitude is used for subsequent fitting input. The proportion of the remaining interference amplitude is represented by c, and the remaining interference amplitude of the reference pole or electrode is Xa. 01 , position detection data is adjusted to X0-Xa 02 =X 01 , the residual interference amplitude at the target catheter position is X a -Xa 02=Xa1, the adjusted catheter position data is X-Xa 02 =X1, expressed as X1.

[0044] In step 6, the reference position data X detected multiple times in one or more breathing cycles is 01 The remaining part of the reference breathing interference amplitude Xa 01 The set is substituted into the conversion equation of the three-dimensional space coordinate data for conversion, and the three-dimensional space coordinate data of the reference magnetic pole or electrode is obtained, which is expressed as the set of Y0. The conversion process is F(X 01 , Xa 01 )=Y0, and we get Xa 01 All coefficients C in the F conversion equation;

[0045] In step S7, the position data of the target catheter and the obtained fitting parameter C are substituted into the same three-dimensional space conversion equation F(C)(X1, Xa1) to calculate and obtain the position coordinate Y1 of the catheter in the three-dimensional space;

[0046] In step S8, the spatial position coordinate Y1 of the catheter is extracted according to the respiratory disturbance period T of the reference magnetic pole or electrode, and compared with the legality threshold and the periodic change law obtained by previous calculations, so that the calculated target catheter respiratory disturbance data does not exceed the legal threshold and is consistent with the corresponding respiratory disturbance results in previous respiratory cycles. The obtained respiratory disturbance result is expressed as Y a , subtract the position deviation caused by respiratory disturbance from the three-dimensional spatial coordinate result of the target catheter to obtain the final spatial position data Y1-Y a =Y. According to the above processing, the three-dimensional spatial position coordinate value of the target catheter magnetic pole or electrode is finally obtained after removing the disturbance caused by breathing.

[0047] Figure 3 The structure diagram of the cardiac three-dimensional mapping system is illustrated. The position signal of the catheter on the endocardium can be used to construct a three-dimensional cardiac cavity model. The signal is processed by the signal processing module 102 to generate a three-dimensional cardiac graphic and an activation signal combined graphic representation, which is displayed on the display device 103 (usually a display); Figure 4 An exemplary three-dimensional image of a heart and one or more catheters 201 therein is displayed on a display device.

[0048] The present invention has been disclosed as above with preferred implementation cases, but it is not used to limit the present invention. Any technician familiar with the profession can make slight changes or modifications to equivalent implementation cases with equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention, which still fall within the scope of the technical solution of the present invention.

Claims

1. A method for eliminating respiratory interference in catheter position detection during three-dimensional model reconstruction, characterized in that: Include: S1, receiving position data of electrodes or magnetic poles on a target catheter; S2, receiving position data of a reference electrode or a magnetic pole; S3, extracting interference amplitude and periodic phase from the reference electrode or magnetic pole; The positioning data of the target catheter electrode or magnetic pole and the reference electrode or magnetic pole received in step 1 and step 2 are represented by X and X0, respectively. The amplitude and period of the respiratory disturbance of the reference electrode or magnetic pole in step S3 are represented by Xa0 and T, respectively. The target catheter position data and the respiratory disturbance amplitude are compared with the legal threshold value, so that the amplitude of the respiratory disturbance received by the target catheter does not exceed the predefined threshold value, and the amplitude of the respiratory disturbance of the target catheter position is obtained as X a ; S4, extracting the amplitude and cycle phase of respiratory disturbances from the target catheter electrode or magnetic pole and comparing them with legal thresholds; S5, calculating the ratio and baseline difference of the respiratory disturbance data detected by the reference electrode or magnetic pole and the target catheter electrode or magnetic pole, and removing the baseline difference at the same time; The calculation process of step 5 is: Xa0 = Xa 01 +Xa 02 ,X a =c*Xa 01 +Xa 02 , according to the continuous calculation and fitting, Xa 02 The value is between 0.6 and 0.8 times of Xa0, and Xa is removed from the position data of the reference magnetic pole or electrode and the target catheter magnetic pole or electrode. 02 , but retain the same 01 The relevant interference amplitude is used for subsequent fitting input. The proportion of the remaining interference amplitude is represented by c, and the remaining interference amplitude of the reference pole or electrode is Xa. 01 , position detection data is adjusted to X0-Xa 02 =X 01 , the residual interference amplitude at the target catheter position is X a -Xa 02 =Xa1, the adjusted catheter position data is X-Xa 02 =X1, expressed as X1; S6. Fitting the reference electrode or magnetic pole position data with an equation to calculate the parameters of the effect of respiratory disturbance on the spatial position coordinates; S7, performing interference elimination calculation on the three-dimensional spatial position of the catheter electrode or magnetic pole using the parameters obtained by fitting the reference electrode or magnetic pole; S8. Extract the spatial interference value that conforms to the law of previous respiratory cycles from the processed target catheter position data, and make a comprehensive judgment with the legal threshold to obtain the final catheter position data.

2. According to the method for eliminating respiratory interference in catheter position detection in three-dimensional model reconstruction according to claim 1, it is characterized by: In step 4, it is first determined whether the position of the catheter has undergone a large mutation. When the change speed and amplitude are relatively stable, the catheter disturbance amplitude is extracted. Otherwise, a reasonable estimation should be made based on the existing change amplitude and reference respiratory phase.

3. The method for eliminating respiratory interference in catheter position detection during three-dimensional model reconstruction according to claim 1, characterized in that: In step 8, it is first determined whether the position of the catheter has undergone a large mutation. When the change speed and amplitude are relatively stable, the catheter disturbance amplitude is extracted. Otherwise, a reasonable estimation should be made based on the existing change amplitude and reference respiratory phase.

4. The method for eliminating respiratory interference in catheter position detection during three-dimensional model reconstruction according to claim 1, characterized in that: The fitting function of the equation fitting in step 6 is a first-order or multi-order polynomial or a B-spline function.

5. The method for eliminating respiratory interference in catheter position detection in three-dimensional model reconstruction according to claim 1, characterized in that: In step 6, the reference position data X detected multiple times in one or more breathing cycles is 01 The remaining part of the reference breathing interference amplitude Xa 01 The set is substituted into the conversion equation of the three-dimensional space coordinate data for conversion, and the three-dimensional space coordinate data of the reference magnetic pole or electrode is obtained, which is expressed as the set of Y0. The conversion process is F(X 01 , Xa 01 )=Y0, and we get Xa 01 All coefficients in the F conversion equation are C.

6. The method for eliminating respiratory interference in catheter position detection in three-dimensional model reconstruction according to claim 5, characterized in that: In step S7, the position data of the target catheter and the obtained fitting parameter C are substituted into the same three-dimensional space conversion equation F(C)(X1, Xa1) for calculation to obtain the position coordinate Y1 of the catheter in the three-dimensional space.

7. The method for eliminating respiratory interference in catheter position detection in three-dimensional model reconstruction according to claim 6, characterized in that: In step S8, the spatial position coordinate Y1 of the catheter is extracted according to the respiratory disturbance period T of the reference magnetic pole or electrode, and compared with the legality threshold and the periodic change law obtained by previous calculations, so that the calculated target catheter respiratory disturbance data does not exceed the legal threshold and is consistent with the corresponding respiratory disturbance results in previous respiratory cycles. The obtained respiratory disturbance result is expressed as Y a , subtract the position deviation caused by respiratory disturbance from the three-dimensional spatial coordinate result of the target catheter to obtain the final spatial position data Y1-Y a =Y.

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