CN100546540C

Movatterモバイル変換

Info

Publication number: CN100546540C
Application number: CNB2006101161773A
Authority: CN
Inventors: 张勇; 沈海东; 徐丹红; 叶有利
Original assignee: SHANGHAI HONGTONG INDUSTRY Co Ltd
Current assignee: SHANGHAI HONGTONG INDUSTRY Co Ltd
Priority date: 2006-09-19
Filing date: 2006-09-19
Publication date: 2009-10-07
Anticipated expiration: 2026-09-19
Also published as: CN101147676A

Abstract

本发明公开了一种心内膜三维导航系统和导航方法，它改进了腔内的导管定位技术，使得结构简单、导航精度高。其技术方案为：系统包括：激励装置、三对激励电极、导管位置信号获取装置、呼吸阻抗调整装置、心腔机械外形同步装置，其中激励装置中的数字控制逻辑和恒流发生模块，同时产生三个低于10KHz的不同的连续正弦波，导管位置信号获取装置包括导管、定位放大器、模数转换器、数字解调器和坐标转换模块，呼吸阻抗调整装置包括体表电场信号采集电极、定位放大器、模数转换器、呼吸数据提取模块、呼吸校准模块。本发明应用于心内科导管介入手术的领域。

The invention discloses an endocardial three-dimensional navigation system and a navigation method, which improves the intracavity catheter positioning technology, makes the structure simple and the navigation precision is high. Its technical solution is: the system includes: an excitation device, three pairs of excitation electrodes, a catheter position signal acquisition device, a breathing impedance adjustment device, and a heart cavity mechanical shape synchronization device, wherein the digital control logic and the constant current generation module in the excitation device simultaneously generate Three different continuous sine waves below 10KHz. The catheter position signal acquisition device includes a catheter, a positioning amplifier, an analog-to-digital converter, a digital demodulator, and a coordinate conversion module. The respiratory impedance adjustment device includes a body surface electric field signal acquisition electrode, a positioning Amplifier, analog-to-digital converter, respiration data extraction module, respiration calibration module. The invention is applied to the field of catheter intervention operation in the department of cardiology.

Description

Translated fromChinese

心内膜三维导航系统Endocardial three-dimensional navigation system

技术领域technical field

本发明涉及一种手术导航系统，尤其涉及一种在心内科的导管介入手术中进行导管导航的系统。The invention relates to an operation navigation system, in particular to a catheter navigation system in the catheter intervention operation of the Department of Cardiology.

背景技术Background technique

在心内科导管介入手术中，需要通过导航技术对导管进行导航。导管的导航技术简述如下：通过取得导管在心内膜上的位置信号来构建一个三维的心腔模型，在三维心腔模型上观察导管信号位置，以获得导管在心内膜上的实际位置，便于医生在手术中的操作。In cardiology catheter interventional surgery, it is necessary to navigate the catheter through navigation technology. The catheter navigation technology is briefly described as follows: a three-dimensional cardiac cavity model is constructed by obtaining the position signal of the catheter on the endocardium, and the signal position of the catheter is observed on the three-dimensional cardiac cavity model to obtain the actual position of the catheter on the endocardium. The doctor's operation during the operation.

现有的心内膜三维导航方法一般包括以下几个步骤：用三对空间位置正交的激励电极放置在体表上，对激励电极加电以形成三维电场；导管电极采集导管所处位置在三维电场中的电场信号，根据电场信号计算出导管的位置信息；考虑到呼吸引起的形变对电场的影响，还需要对导管的位置信息作一个校正；将校正后的导管位置信息在某一特定时刻作一个同步；根据同步后的导管位置信息形成一个三维心腔模型。The existing three-dimensional endocardial navigation method generally includes the following steps: three pairs of excitation electrodes with orthogonal spatial positions are placed on the body surface, and the excitation electrodes are powered to form a three-dimensional electric field; the catheter electrode collection catheter is located at The electric field signal in the three-dimensional electric field, the position information of the catheter is calculated according to the electric field signal; considering the influence of the deformation caused by breathing on the electric field, a correction is also required for the position information of the catheter; the corrected catheter position information is in a specific Synchronize at all times; form a three-dimensional cardiac chamber model based on the synchronized position information of the catheter.

公开号为US2004/0254437的美国专利申请“METHOD AND APPARATUS FORCATHETER NAVIGATION AND LOCATION AND MAPPING IN THE HEART”公开了一种导航定位系统，该导航定位系统通过分时方式驱动激励电极获得携带呼吸信息的数据，并将这些数据线性加权后从获得导管位置数据中减去这些数据。该申请的缺点在于：(a)针对呼吸波的处理技术，采用时分系统采集呼吸波形数据，由于激励和采集必须在同一平面内的相互不正交的电极对之间进行，所以能够采集的电极组合模式有限，从而提取的呼吸相关信息也不够丰富，电路结构复杂；(b)采用了一种线性加权的方法补偿呼吸波形的影响，模型简单，计算误差大；(c)采用电流脉冲的形式产生外部激励，易受电极系统接触电容的影响，而且采集的呼吸波数据处理算法精度有限。The U.S. patent application "METHOD AND APPARATUS FORCATHETER NAVIGATION AND LOCATION AND MAPPING IN THE HEART" with the publication number US2004/0254437 discloses a navigation and positioning system, which drives the excitation electrodes in a time-sharing manner to obtain data carrying respiratory information. These data are linearly weighted and subtracted from the obtained catheter position data. The disadvantages of this application are: (a) for the processing technology of respiratory waves, a time-division system is used to collect respiratory waveform data. Since the excitation and collection must be carried out between mutually non-orthogonal electrode pairs in the same plane, the electrodes that can be collected The combination mode is limited, so the extracted breathing-related information is not rich enough, and the circuit structure is complicated; (b) a linear weighting method is used to compensate the influence of the breathing waveform, the model is simple, and the calculation error is large; (c) the form of current pulse is used The external excitation is easily affected by the contact capacitance of the electrode system, and the accuracy of the collected respiratory wave data processing algorithm is limited.

发明内容Contents of the invention

本发明的目的在于解决上述问题，提供了一种心内膜三维导航系统，它改进了腔内的导管定位技术，使得结构简单、导航精度高。The purpose of the present invention is to solve the above problems, and provides a three-dimensional endocardial navigation system, which improves the catheter positioning technology in the cavity, and makes the structure simple and the navigation precision high.

本发明的技术方案为：一种心内膜三维导航系统，用于心内膜上导管的导航，所述系统包括：The technical solution of the present invention is: a three-dimensional endocardial navigation system for navigating a supraendocardial catheter, the system comprising:

一激励装置，包括：An incentive device comprising:

数字控制逻辑和恒流发生模块，同时产生三个低于10KHz的不同的连续正弦波；和Digital control logic and constant current generation module, simultaneously generating three different continuous sine waves below 10KHz; and

三对激励电极，位于体表且在空间位置上相互正交，与所述数字控制逻辑和恒流发生模块连接，所述三个连续正弦波分别加载在该三对激励电极上，在体内形成三维的低频稳恒电场；Three pairs of excitation electrodes are located on the body surface and are orthogonal to each other in spatial position, connected with the digital control logic and the constant current generation module, and the three continuous sine waves are respectively loaded on the three pairs of excitation electrodes to form a Three-dimensional low-frequency steady electric field;

一导管位置信号获取装置，包括：A catheter position signal acquisition device, comprising:

导管，位于心内膜上，所述导管上附有电极，用于提取所述导管在所述激励电极形成的三维电场中的电场信号；a catheter, located on the endocardium, with electrodes attached to the catheter for extracting the electric field signal of the catheter in the three-dimensional electric field formed by the excitation electrodes;

第一定位放大器，连接所述导管电极，用于对提取的电场信号进行放大；a first positioning amplifier, connected to the catheter electrode, for amplifying the extracted electric field signal;

第一模数转换器，连接所述第一定位放大器，用于将放大后的电场信号转换成数字信号；A first analog-to-digital converter, connected to the first positioning amplifier, for converting the amplified electric field signal into a digital signal;

数字解调器，连接所述第一模数转换器，用于在转换后的数字信号中提取导管位置的电场信号强度信息；和a digital demodulator, connected to the first analog-to-digital converter, for extracting the electric field signal strength information of the catheter position from the converted digital signal; and

坐标转换模块，将导管位置的电场信号强度信息转换成导管位置信号；A coordinate transformation module, which converts the electric field signal intensity information of the catheter position into a catheter position signal;

一呼吸阻抗调整装置，包括：A breathing impedance adjustment device, comprising:

体表电场信号采集电极，采集的体表电场信号包含肺部体积变化的信息；Electrodes for collecting body surface electric field signals, and the collected body surface electric field signals include information on changes in lung volume;

第二定位放大器，连接所述体表电场信号采集电极，用于对采集到的体表电场信号进行放大；The second positioning amplifier is connected to the body surface electric field signal acquisition electrode, and is used to amplify the collected body surface electric field signal;

第二模数转换器，连接所述第二定位放大器，用于将放大后的体表电场信号转换成数字信号；A second analog-to-digital converter, connected to the second positioning amplifier, for converting the amplified body surface electric field signal into a digital signal;

呼吸数据提取模块，连接所述第二模数转换器，用于提取呼吸阻抗的变化信息；和A respiratory data extraction module, connected to the second analog-to-digital converter, for extracting change information of respiratory impedance; and

呼吸校准模块，输入端连接所述呼吸数据提取模块和所述导管位置信号获取装置中的数字解调器，输出端连接导管位置信号获取装置中的坐标转换模块的输入端，从导管位置的电场信号强度信息中剔除呼吸阻抗的变化信息造成的伪差，输出得到校准的导管位置的电场信号强度信息；Respiration calibration module, the input end is connected to the digital demodulator in the respiration data extraction module and the catheter position signal acquisition device, the output end is connected to the input end of the coordinate conversion module in the catheter position signal acquisition device, and the electric field from the catheter position In the signal strength information, the artifact caused by the change information of the respiratory impedance is eliminated, and the electric field signal strength information of the calibrated catheter position is output;

一心腔机械外形同步装置，包括：A cardiac cavity mechanical shape synchronization device, including:

心脏同步信号提取模块，采集包含心脏搏动周期信息的电生理信号；和A cardiac synchronous signal extraction module, which collects electrophysiological signals containing cardiac cycle information; and

同步处理模块，输入端连接所述心脏同步信号提取模块的输出端和坐标转换模块的输出端，将导管位置信号的更新与心内膜外形的周期性变化进行同步处理。Synchronization processing module, the input end of which is connected to the output end of the cardiac synchronous signal extraction module and the output end of the coordinate conversion module, and performs synchronous processing on the update of the catheter position signal and the periodic change of the endocardial shape.

上述的心内膜三维导航系统，其中，所述数字控制逻辑和恒流发生模块产生的三个低于10KHz的不同的连续正弦波的频率范围是4～6KHz；所述第一模数转换器和第二模数转换器是高分辨率音频模数转换器。The above three-dimensional endocardial navigation system, wherein the frequency range of the three different continuous sine waves lower than 10KHz generated by the digital control logic and the constant current generation module is 4-6KHz; the first analog-to-digital converter and the second analog-to-digital converter is a high-resolution audio analog-to-digital converter.

上述的心内膜三维导航系统，其中，所述呼吸阻抗调整装置中体表电场信号采集电极包括所述激励电极和体表ECG电极。In the above three-dimensional endocardial navigation system, wherein the body surface electric field signal acquisition electrodes in the respiratory impedance adjustment device include the excitation electrodes and body surface ECG electrodes.

上述的心内膜三维导航系统，其中，所述心腔机械外形同步装置中心脏同步信号提取模块的信号源包括血液动力学指标、生物化学指标。In the above-mentioned three-dimensional endocardial navigation system, the signal source of the cardiac synchronization signal extraction module in the cardiac cavity mechanical shape synchronization device includes hemodynamic indicators and biochemical indicators.

上述的心内膜三维导航系统，其中，所述第一定位放大器和/或第二定位放大器还设有一自动校准装置，所述自动校准装置包括：In the above-mentioned three-dimensional endocardial navigation system, wherein, the first positioning amplifier and/or the second positioning amplifier are also provided with an automatic calibration device, and the automatic calibration device includes:

温度探测器，用于探测环境温度是否发生改变；A temperature detector, used to detect whether the ambient temperature has changed;

校准控制模块，连接所述温度探测器，在温度探测器探测到温度发生改变后启动校准过程，控制所述第一定位放大器和/或第二定位放大器进入校准模式；A calibration control module, connected to the temperature detector, starts the calibration process after the temperature detector detects that the temperature has changed, and controls the first positioning amplifier and/or the second positioning amplifier to enter the calibration mode;

校准信号发生器，连接所述校准控制模块，在校准控制模块启动校准过程后产生一初始校准信号；A calibration signal generator, connected to the calibration control module, generates an initial calibration signal after the calibration control module starts the calibration process;

幅度提取模块，输入端连接所述数字解调器，输出端连接所述校准控制模块，所述幅度提取模块输出带有误差的校准信号强度至所述校准控制模块，所述校准控制模块根据初始校准信号的强度与带有误差校准信号的强度计算出放大误差，所述误差作为补偿控制该第一定位放大器和/或第二定位放大器的放大增益。Amplitude extraction module, the input end is connected to the digital demodulator, the output end is connected to the calibration control module, the amplitude extraction module outputs the calibration signal strength with error to the calibration control module, and the calibration control module is based on the initial The magnitude of the calibration signal and the magnitude of the calibration signal with error calculate an amplification error which controls the amplification gain of the first positioning amplifier and/or of the second positioning amplifier as compensation.

上述的心内膜三维导航系统，其中，所述呼吸校准模块进一步包括：The above three-dimensional endocardial navigation system, wherein the breathing calibration module further includes:

滤波单元，输入端接收导管电极的固定位置信号以及体表电场信号采集电极采集到的阻抗变化信息，输出导管电极的阻抗变化信息和体表电场信号采集电极的阻抗变化信息；The filter unit receives the fixed position signal of the catheter electrode and the impedance change information collected by the body surface electric field signal acquisition electrode at the input end, and outputs the impedance change information of the catheter electrode and the impedance change information of the body surface electric field signal acquisition electrode;

呼吸模型参数提取单元，输入端连接所述滤波单元的输出端，以体表电场信号采集电极的阻抗变化信息作为输入信号，通过标准最小均方算法变换组合输入信号以使其逼近导管电极的固定位置信号，达到最优逼近后呼吸模型的参数被输出，其中变换组合输入信号的结果逼近导管电极的固定位置信号的误差小于等于0.2mm即为最优逼近；Breathing model parameter extraction unit, the input end is connected to the output end of the filter unit, the impedance change information of the body surface electric field signal acquisition electrode is used as the input signal, and the combined input signal is transformed through the standard least mean square algorithm to make it approach the fixed position of the catheter electrode. The position signal, the parameters of the respiratory model are output after the optimal approximation is reached, and the error of the result of transforming the combined input signal to the fixed position signal of the catheter electrode is less than or equal to 0.2mm is the optimal approximation;

参数应用单元，输入端连接所述滤波单元和呼吸模型参数提取单元，根据呼吸模型的参数对体表电场信号采集电极的阻抗变化信息按照该呼吸模型参数提取单元所提取的呼吸模型进行变换组合，输出一个校准波形信号；A parameter application unit, the input end of which is connected to the filter unit and the respiratory model parameter extraction unit, and according to the parameters of the respiratory model, the impedance change information of the body surface electric field signal acquisition electrode is transformed and combined according to the respiratory model extracted by the respiratory model parameter extraction unit, Output a calibration waveform signal;

减法单元，输入端连接所述数字解调器和所述参数应用单元，从导管电极位置信号中减去校准波形信号，输出得到校准的导管位置的电场信号强度信息。A subtraction unit, the input end of which is connected to the digital demodulator and the parameter application unit, subtracts the calibration waveform signal from the catheter electrode position signal, and outputs the calibrated electric field signal intensity information at the catheter position.

上述的心内膜三维导航系统，其中，所述系统还包括图形显示装置，输入端连接所述同步处理模块，用于根据同步后的导管位置信号建立心腔的三维模型。In the above-mentioned three-dimensional endocardial navigation system, the system further includes a graphic display device, the input end of which is connected to the synchronization processing module, and is used to establish a three-dimensional model of the heart chamber according to the synchronized catheter position signal.

上述的心内膜三维导航系统，其中，所述系统还包括电生理信号标测装置，所述电生理信号标测装置包括：The above three-dimensional endocardial navigation system, wherein the system further includes an electrophysiological signal mapping device, and the electrophysiological signal mapping device includes:

电生理信号采集电极，包括ECG电极和导管电极，采集人体的电生理信号；Electrophysiological signal acquisition electrodes, including ECG electrodes and catheter electrodes, collect electrophysiological signals of the human body;

电生理信号放大器，连接所述电生理信号采集电极，将采集到的人体电生理信号进行放大；An electrophysiological signal amplifier, connected to the electrophysiological signal acquisition electrodes, amplifies the collected human electrophysiological signals;

模数转换器，连接所述电生理信号放大器，将放大后的人体电生理信号转换成数字信号；An analog-to-digital converter, connected to the electrophysiological signal amplifier, converts the amplified human electrophysiological signal into a digital signal;

电生理信号提取模块，连接所述模数转换器，从数字信号中提取心腔内特定位置的电生理活动信息并作为输出。The electrophysiological signal extraction module is connected to the analog-to-digital converter, and extracts the electrophysiological activity information of a specific position in the heart cavity from the digital signal as an output.

本发明对比现有技术有如下的有益效果：本发明有区别现有技术的如下特征：以分频率正弦波的激励技术以及多体表电极的呼吸数据的收集技术，驱动电极同时是采样电极。对采集到的电场信号先进行模数转换再进行数字解调。在呼吸信号的处理方面用ECG电极和激励电极共同获取电场信号。利用血液的动力学或者生物化学指标作为同步信号的输入，以确定导管在心脏搏动周期某个时刻的位置。自动校准定位放大器。本发明具有结构简单、校准简便、处理算法先进、导航精度高等优点。Compared with the prior art, the present invention has the following beneficial effects: the present invention has the following characteristics different from the prior art: the excitation technology of frequency division sine wave and the collection technology of respiratory data of multiple body surface electrodes, and the driving electrodes are sampling electrodes at the same time. The collected electric field signal is first converted to analog and then digitally demodulated. In the processing of respiratory signals, ECG electrodes and excitation electrodes are used to jointly acquire electric field signals. The blood dynamics or biochemical indicators are used as the input of the synchronous signal to determine the position of the catheter at a certain moment in the cardiac beating cycle. Automatically calibrates the positioning amplifier. The invention has the advantages of simple structure, convenient calibration, advanced processing algorithm, high navigation precision and the like.

附图说明Description of drawings

图1是本发明的心内膜三维导航系统的一个较佳实施例的框图。Fig. 1 is a block diagram of a preferred embodiment of the endocardial three-dimensional navigation system of the present invention.

图2是本发明的激励电极实施例的示意图。Fig. 2 is a schematic diagram of an embodiment of an excitation electrode of the present invention.

图3是本发明的呼吸校准模块的实施例的框图。Figure 3 is a block diagram of an embodiment of the breath calibration module of the present invention.

具体实施方式Detailed ways

下面结合附图和实施例对本发明作进一步的描述。The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

图1示出了本发明的心内膜三维导航系统的一个较佳实施例。请参见图1，心内膜三维导航系统10包括以下几个部分：激励装置、导管位置信号获取装置、呼吸阻抗调整装置、心腔机械外形同步装置、图形显示装置、电生理信号标测装置。Fig. 1 shows a preferred embodiment of the three-dimensional endocardial navigation system of the present invention. Please refer to FIG. 1 , the endocardial three-dimensional navigation system 10 includes the following parts: an excitation device, a catheter position signal acquisition device, a respiratory impedance adjustment device, a cardiac cavity mechanical shape synchronization device, a graphic display device, and an electrophysiological signal mapping device.

激励装置由数字控制逻辑和恒流发生模块11和与之连接的激励电极组12组成。请同时参见图2，激励电极组12位于体表，包括三对空间位置上正交的激励电极：X方向激励电极121、Y方向激励电极122和Z方向激励电极123。数字控制逻辑和恒流发生模块11产生三个低于10KHz的不同的连续正弦波，分别加载在这三对激励电极121～123上，在体内形成一个三维的低频稳恒电场。较佳地，正弦波的频率控制在4～6KHz。The excitation device is composed of a digital control logic and a constant current generation module 11 and an excitation electrode group 12 connected thereto. Please also refer to FIG. 2 , the excitation electrode group 12 is located on the body surface, and includes three pairs of excitation electrodes orthogonal to each other in space: anX-direction excitation electrode 121 , a Y-direction excitation electrode 122 and a Z-direction excitation electrode 123 . The digital control logic and constant current generation module 11 generates three different continuous sine waves below 10KHz, which are respectively loaded on the three pairs of excitation electrodes 121-123, forming a three-dimensional low-frequency stable electric field in the body. Preferably, the frequency of the sine wave is controlled at 4-6KHz.

本发明的发明点之一在于：加载在激励电极上的信号是数KHz的不同的连续正弦波。主要基于如下考虑：由于电极与人体之间，人体内部存在许多非线性的效应。对一些谐波丰富的激励方式，如采用高频脉冲激励的方式或者正弦波分时激励的方式，容易造成较大的误差，比较而言唯有采用连续的单频率的正弦波才能将这种非线性导致的测量误差减小到最低。其次，由于在临床应用中一些产品需要借助电脉冲激励来获取病人的呼吸、心跳的每搏输出量等生理参数相关的等阻抗信息，这些测试设备一般采用的激励信号为几十KHz，所以本申请选用的数KHz的激励频率可以有效避开这些设备的工作频率范围从而提高设备在使用上的兼容性。One of the inventive points of the present invention is that the signals loaded on the excitation electrodes are different continuous sine waves of several KHz. It is mainly based on the following considerations: due to the connection between the electrode and the human body, there are many nonlinear effects inside the human body. For some excitation methods rich in harmonics, such as the use of high-frequency pulse excitation or sine wave time-sharing excitation, it is easy to cause large errors. In comparison, only continuous single-frequency sine waves can Measurement errors caused by non-linearities are minimized. Secondly, because some products in clinical applications need to use electric pulse excitation to obtain the equal impedance information related to physiological parameters such as the patient's respiration and heartbeat output per stroke, these test equipment generally use excitation signals of tens of KHz, so this The excitation frequency of a few KHz applied for selection can effectively avoid the operating frequency range of these devices and thus improve the compatibility of the devices in use.

导管位置信号获取装置包括位于心内膜13上的导管、定位放大器15、模数转换器16、数字解调器17和坐标转换模块18。呼吸阻抗调整装置包括用于采集体表电场信号的激励电极组12和体表ECG电极19、定位放大器15、模数转换器16、呼吸数据提取模块20和呼吸校准模块21。另外，在这些电极与定位放大器15之间还设有一个缓冲器22。在本实施例中，呼吸阻抗调整装置和导管位置信号获取装置的定位放大器和模数转换器是同一个，本实施例仅作为示例，两者的定位放大器和模数转换器也可以分开设置。The catheter position signal acquisition device includes a catheter located on the endocardium 13 , a positioning amplifier 15 , an analog-to-digital converter 16 , a digital demodulator 17 and a coordinate conversion module 18 . The breathing impedance adjustment device includes an excitation electrode group 12 and a body surface ECG electrode 19 for collecting body surface electric field signals, a positioning amplifier 15 , an analog-to-digital converter 16 , a breathing data extraction module 20 and a breathing calibration module 21 . In addition, a buffer 22 is provided between these electrodes and the positioning amplifier 15 . In this embodiment, the positioning amplifier and analog-to-digital converter of the respiratory impedance adjustment device and the catheter position signal acquisition device are the same, this embodiment is only an example, and the positioning amplifier and analog-to-digital converter of the two can also be set separately.

在导管位置信号获取装置中，导管上安装有导管电极14，采集导管在三维电场中的电场信号，经缓冲器22在定位放大器15中被放大，再经模数转换器16转换成数字信号，由数字解调器17从数字信号中提取导管位置的电场信号强度信息。本实施例，正弦波的频率降低到数KHz，处于典型的音频范围内，因此可以用高分辨率音频模数转换器作为模数转换器16。音频模数转换器的使用可以提高系统的信噪比，进一步降低放大器设计复杂度，而且接口也具有成熟的工业标准。In the catheter position signal acquisition device, the catheter electrode 14 is installed on the catheter, and the electric field signal of the catheter in the three-dimensional electric field is collected, amplified by the buffer 22 in the positioning amplifier 15, and then converted into a digital signal by the analog-to-digital converter 16, The electric field signal strength information at the catheter position is extracted from the digital signal by the digital demodulator 17 . In this embodiment, the frequency of the sine wave is reduced to several KHz, which is within the typical audio range, so a high-resolution audio analog-to-digital converter can be used as the analog-to-digital converter 16 . The use of audio analog-to-digital converters can improve the signal-to-noise ratio of the system, further reduce the complexity of amplifier design, and the interface also has a mature industry standard.

在数字解调器17中，可以采用常见的信号处理方法来提取此刻代表导管位置的正弦信号的幅度。针对本实施例中单频率正弦信号的幅度提取，有许多可以使用的处理算法，DFT算法是一种常见的高效的处理算法。DFT的典型算式如下： $X (k) = Σ_{n = 0}^{N - 1} x (n) [\cos \frac{2 πnk}{N} - j \sin \frac{2 πnk}{N}],$ X(k)为规一化后的采样信号的DFT的某个频率的值，取激励的三个频率信号为Fx，Fy，Fz，以求取Fx频率的信号幅度为例，为了防止频谱泄漏，要求算式中长度为N的x(j)序列中包含整数个频率为Fx以及(Fx-Fy)，(Fx-Fz)的完整的波形周期。而为了确保算法实现的效率则要求X，Y，Z三个频率的计算采用相同的序列长度，同时如果在50Hz电源的工作环境中则期望进行解调的算法周期为20ms。采样率Fs和Fx，Fy，Fz之间需要均衡以满足这些条件。In the digital demodulator 17, common signal processing methods can be used to extract the amplitude of the sinusoidal signal representing the position of the catheter at that moment. For the amplitude extraction of the single-frequency sinusoidal signal in this embodiment, there are many processing algorithms that can be used, and the DFT algorithm is a common and efficient processing algorithm. The typical calculation formula of DFT is as follows: $x (k) = Σ_{no = 0}^{N - 1} x (no) [\cos \frac{2 πnk}{N} - j \sin \frac{2 πnk}{N}],$ X(k) is the value of a certain frequency of the DFT of the normalized sampling signal. The three frequency signals of the excitation are Fx, Fy, and Fz. Taking the signal amplitude of the Fx frequency as an example, in order to prevent spectrum leakage , it is required that the x(j) sequence with length N in the formula contains an integer number of complete waveform periods with frequencies Fx and (Fx-Fy), (Fx-Fz). In order to ensure the efficiency of the algorithm implementation, it is required that the calculation of the three frequencies of X, Y, and Z adopts the same sequence length, and at the same time, if the working environment of the 50Hz power supply is used, the algorithm period for demodulation is expected to be 20ms. A balance is required between the sampling rate Fs and Fx, Fy, Fz to satisfy these conditions.

DFT变换的结果包含的复数信息提示了经过人体调制后的信号中的相位信息，即本地的正弦信号与激励源的信号的相位差，而有用的信息却是最后结果的模，由于本发明的ADC转换和激励信号的发生都是在同一颗数字芯片中完成的，激励和采样的信号可以严格的同步，所以通过调节数字解调时，本振的相位可以把解调后的相位差控制在0度附近，进而可以使得最后的DFT结果的虚部始终为零，从而可以将DFT模的求取简化为仅仅是实部的计算，这样可以将DFT的计算开销减少50％。The complex number information contained in the result of DFT transformation suggests the phase information in the signal modulated by the human body, that is, the phase difference between the local sinusoidal signal and the signal of the excitation source, but the useful information is the modulus of the final result, because the present invention ADC conversion and excitation signal generation are completed in the same digital chip, and the excitation and sampling signals can be strictly synchronized, so by adjusting the digital demodulation, the phase of the local oscillator can control the phase difference after demodulation. Near 0 degrees, so that the imaginary part of the final DFT result is always zero, so that the calculation of the DFT modulus can be simplified to only the calculation of the real part, which can reduce the calculation cost of DFT by 50%.

本发明的另一个发明点在于：对采集到的电场信号先进行模数转换，再进行数字解调处理。这也是基于激励信号是数KHz正弦波，低频率提高了数字解调的精度，使提取到的电场信号强度更为准确。Another inventive point of the present invention is that the collected electric field signal is firstly converted into analog to digital, and then digitally demodulated. This is also based on the fact that the excitation signal is a sine wave of several KHz, and the low frequency improves the accuracy of digital demodulation, making the extracted electric field signal strength more accurate.

考虑到呼吸形变引起电场的变化，即使导管被固定，在呼吸形变的影响下腔内电场发生轻微的改变，导管所处位置的电场信号也会随之发生变化。导管在固定的位置，其电场信号也将发生变化，显然会导致后续的推导位置信号的误差。上述的呼吸阻抗调整装置就起到了调整呼吸形变误差的作用。激励电极组12在腔内形成三维电场的同时也会在体表形成一个电场，呼吸导致的肺阻抗的变化可以在体表电场的变化上予以体现，所以本系统从体表直接使用电极获取阻抗相关的数据。位于体表的激励电极组12和多个ECG电极19(图中仅示出一个)采集自身所处位置的体表电场信号，这些信号包换了肺部体积变化的信息。体表电场信号经定位放大器15放大，模数转换器16转换成数字信号后，在呼吸数据提取模块20中提取呼吸阻抗的变化信息。呼吸校准模块21接收呼吸提取模块20的呼吸阻抗变化信息以及数字解调器17的导管位置电场信号强度信息，从导管位置电场信号强度信息中剔除呼吸阻抗变化信息造成的伪差，输出经过校准的导管位置信号。Considering the change of electric field caused by respiratory deformation, even if the catheter is fixed, the electric field in the cavity changes slightly under the influence of respiratory deformation, and the electric field signal at the position of the catheter will also change accordingly. When the catheter is at a fixed position, its electric field signal will also change, which will obviously lead to errors in the subsequent position signal derivation. The above-mentioned breathing impedance adjustment device has the function of adjusting the breathing deformation error. The excitation electrode group 12 forms a three-dimensional electric field in the cavity and also forms an electric field on the body surface, and the change of lung impedance caused by breathing can be reflected in the change of the body surface electric field, so this system directly uses electrodes from the body surface to obtain impedance related data. The excitation electrode group 12 and a plurality of ECG electrodes 19 (only one is shown in the figure) located on the body surface collect body surface electric field signals at their own positions, and these signals contain information on changes in lung volume. The body surface electric field signal is amplified by the positioning amplifier 15 , converted into a digital signal by the analog-to-digital converter 16 , and the respiratory impedance change information is extracted in the respiratory data extraction module 20 . The respiratory calibration module 21 receives the respiratory impedance change information of the respiratory extraction module 20 and the electric field signal strength information of the catheter position from the digital demodulator 17, removes the artifact caused by the respiratory impedance change information from the electric field signal strength information of the catheter position, and outputs the calibrated Catheter position signal.

请参见图3，呼吸校准模块21由滤波单元211、呼吸模型参数提取单元212、参数应用单元213和减法单元214组成。呼吸校准模块21的工作流程可以分为两个步骤：模型参数提取和数据应用。Please refer to FIG. 3 , the breathing calibration module 21 is composed of a filtering unit 211 , a breathing model parameter extraction unit 212 , a parameter application unit 213 and a subtraction unit 214 . The workflow of the breathing calibration module 21 can be divided into two steps: model parameter extraction and data application.

导管电极需要被暂时固定，随后从导管电极14收集到的定位信号被用作一个校准输入信号Xc，如果仪器使用过程中某个导管一直处于固定位置(如冠状窦电极导管上一般都静止在冠状窦中)，则校准过程可以被省略，而直接以该固定电极的位置信号作为校准输入信号。The catheter electrode needs to be temporarily fixed, and then the positioning signal collected from the catheter electrode 14 is used as a calibration input signal Xc. sinus), the calibration process can be omitted, and the position signal of the fixed electrode is directly used as the calibration input signal.

Xc带有人体阻抗的数据，和心脏本身搏动导致的导管的瞬态位移以及导管本身所在的空间的静态位置。这三种信号在频域上是分开的，而校准只针对人体阻抗数据进行，所以可以通过滤波单元211将人体阻抗的低频率的变化的信息提取出来，滤波单元可以是0.01～0.5Hz的带通滤波器。从体表ECG电极19和激励电极组12上收集的阻抗信息Yi，同时也经过滤波单元211后，送入呼吸模型参数提取单元212。呼吸模型参数提取单元212的用途是接收阻抗信息Yi作为输入，通过某种数学方法，如标准LMS最小均方算法，变换组合Yi信号，以使变化组合后的结果逼近Xc，达到最优逼近后(如以逼近后的误差作为评判条件，误差小于等效的0.2mm的精度即为最优逼近)，最优数学模型的参数被输出，模型参数提取过程结束，进入数据应用步骤。Xc has the data of human body impedance, the transient displacement of the catheter caused by the beating of the heart itself, and the static position of the space where the catheter itself is located. These three signals are separated in the frequency domain, and the calibration is only performed on the body impedance data, so the information of the low-frequency change of the body impedance can be extracted through the filtering unit 211, and the filtering unit can be 0.01-0.5Hz band pass filter. The impedance information Yi collected from the body surface ECG electrodes 19 and the excitation electrode group 12 is also sent to the respiratory model parameter extraction unit 212 after passing through the filtering unit 211 . The purpose of the breathing model parameter extraction unit 212 is to receive the impedance information Yi as input, and transform and combine the Yi signal through a certain mathematical method, such as the standard LMS least mean square algorithm, so that the result after changing the combination is close to Xc, and after reaching the optimal approximation (For example, the error after the approximation is used as the judgment condition, and the accuracy of the error is less than the equivalent 0.2mm is the optimal approximation), the parameters of the optimal mathematical model are output, the model parameter extraction process ends, and the data application step is entered.

在数据应用过程中，Yi信号经过滤波后持续进入参数应用单元213，该单元213按照上一步骤提取的数学模型来对Yi信号进行变换组合，其输出为一个与Xc经滤波后接近的波形Oc，随后在正常的电场强度信号Mi中与这个波形Oc相关的数据使用减法即可剔除，从而可以得到校准后的导管电场强度信号Ni。During the data application process, the Yi signal continues to enter the parameter application unit 213 after being filtered, and the unit 213 transforms and combines the Yi signal according to the mathematical model extracted in the previous step, and the output is a waveform Oc close to Xc after filtering , then the data related to this waveform Oc in the normal electric field strength signal Mi can be eliminated by subtraction, so that the calibrated catheter electric field strength signal Ni can be obtained.

本发明的又一发明点在于：在本系统的使用环境中，病人身体上一般都连接体表ECG电极，在仅增加很少成本的基础之上，我们利用现有的设计结构，通过ECG电极收集人体的阻抗变化信息，从而可以为针对呼吸的校准措施提供更多的信息。这个信息采集要比背景技术部分介绍的专利申请在实现上要简单很多，而且由于使用分频的方式进行连续激励，对肺部阻抗的检测在时间和空间上也是连续的。更重要的是这样ECG电极兼容阻抗电极的提供呼吸数据的方式可以获取更多的校准信息，从而可以进一步提高校准精度。Another inventive point of the present invention is: in the use environment of this system, the patient's body is generally connected to the ECG electrode on the body surface. On the basis of only adding a small cost, we use the existing design structure to pass the ECG electrode Information on impedance changes in the human body is collected, which can provide more information for calibration measures against respiration. This information collection is much simpler to implement than the patent application introduced in the background technology section, and since the frequency division method is used for continuous excitation, the detection of lung impedance is also continuous in time and space. More importantly, more calibration information can be obtained in such a way that the ECG electrode is compatible with the impedance electrode to provide the respiratory data, thereby further improving the calibration accuracy.

经校准的导管位置的电场信号强度信息在坐标转换模块18中变换成导管位置信号。由于导管在人体的内部是随着心脏跳动的，这里的导管位置信号对应着不同的时刻，所以还是无法确定心脏的实际形状。为了准确获取导管相对心脏的准确位置，需要让导管的位置数据的更新同步于心腔外形的周期性变化。The calibrated electric field signal strength information at the catheter position is transformed into a catheter position signal in the coordinate transformation module 18 . Since the catheter is beating with the heart inside the human body, the catheter position signal here corresponds to different moments, so it is still impossible to determine the actual shape of the heart. In order to accurately obtain the exact position of the catheter relative to the heart, it is necessary to synchronize the update of the position data of the catheter with the periodic change of the shape of the heart chamber.

心内膜机械外形同步装置包括心脏同步信号提取模块22和同步处理模块23。除了采用如体表心电图、腔内心电图等常规电生理信号作为心脏的同步信号外，还采用了其它更符合心腔机械外形结构的同步方式进行同步，如血液的动力学或者生物化学指标作为同步信号源35以供输入，这些同步信号源35中的信号可以是腔内血压信号、无创的血压信号以及血氧饱和度信号等，这些信号的测量技术非常成熟，且与心腔的机械外形周期更具有相关性。电生理信号直接通过本发明中的心内导管和体表电极(如ECG电极19、激励电极组12等)采集后进入心脏同步信号提取模块22，同时同步信号接口可以从其它装置接收诸如血压、血氧饱和度等生理信号。这些信号进入心脏同步信号提取模块22，可选择一种或多种进行同步信息提取，提取方式可以是选择信号波形周期中的某个时刻，如瞬间血压变化最快的时刻、血样浓度最低的时刻或者这些时刻之前的一定时刻作为输出，送入同步处理模块23中以确定导管在心脏搏动周期某个时刻的位置。The endocardial mechanical shape synchronization device includes a cardiac synchronization signal extraction module 22 and a synchronization processing module 23 . In addition to using conventional electrophysiological signals such as body surface electrocardiogram and intracavity electrophysiological signal as the synchronization signal of the heart, other synchronization methods that are more in line with the mechanical shape and structure of the heart chamber are used for synchronization, such as blood dynamics or biochemical indicators as synchronization signals. Signal sources 35 are used for input, and the signals in these synchronous signal sources 35 can be intracavity blood pressure signals, non-invasive blood pressure signals and blood oxygen saturation signals, etc., the measurement technology of these signals is very mature, and the mechanical shape cycle of the heart chamber more relevant. The electrophysiological signal directly enters the cardiac synchronous signal extraction module 22 after being collected by the intracardiac catheter and body surface electrodes (such as ECG electrode 19, excitation electrode group 12, etc.) in the present invention, and the synchronous signal interface can receive data such as blood pressure, Physiological signals such as blood oxygen saturation. These signals enter the cardiac synchronous signal extraction module 22, and one or more can be selected for synchronous information extraction. The extraction method can be to select a certain moment in the signal waveform cycle, such as the moment when the instantaneous blood pressure changes the fastest, and the moment when the blood sample concentration is the lowest Or a certain moment before these moments is used as an output, which is sent to the synchronization processing module 23 to determine the position of the catheter at a certain moment in the heartbeat cycle.

此外，由于单一一种生理信号在采集处理的过程中经常会不可避免的产生伪迹，比如有创血压信号有可能会因为导管的抖动，造成测量结果的抖动，从而引入测量误差，而时电生理信号同时产生伪差的可能性很小，所以多种代表心脏搏动周期的生理信号之间相互比对，以确保同步信号的准确性。In addition, because a single physiological signal often inevitably produces artifacts during the acquisition and processing process, for example, the invasive blood pressure signal may cause the measurement results to jitter due to the jitter of the catheter, thereby introducing measurement errors, and sometimes The possibility of artifacts generated by the electrophysiological signals at the same time is very small, so a variety of physiological signals representing the heartbeat cycle are compared with each other to ensure the accuracy of the synchronous signals.

本发明的又一发明点在于：传统技术只是以体表心电图、腔内心电图等常规电生理信号作为心脏的同步信号，本发明采用了其它更符合心腔机械外形结构的同步方式进行同步，如血液的动力学或者生物化学指标作为同步信号的输入，这些信号可以是腔内血压信号、无创的血压信号以及血氧饱和度信号等，使得同步精度更高。Yet another inventive point of the present invention is: the conventional technology only uses conventional electrophysiological signals such as body surface electrocardiogram and intracavity electrophysiological signal as the synchronous signal of the heart. Blood dynamics or biochemical indicators are used as the input of synchronization signals, and these signals can be intracavitary blood pressure signals, non-invasive blood pressure signals, and blood oxygen saturation signals, etc., so that the synchronization accuracy is higher.

同步处理模块23将导管在心脏搏动周期某时刻的位置信号传输给图形显示装置25，建立心腔的三维图像模型，导管当前位置标识在该模型上。The synchronization processing module 23 transmits the position signal of the catheter at a certain moment in the heartbeat cycle to the graphic display device 25, and establishes a three-dimensional image model of the heart chamber, and the current position of the catheter is marked on the model.

电生理标测装置包括用于采集人体电生理信号的ECG电极19和导管电极14、与ECG电极19连接的ECG放大器27、与导管电极14连接的EP信号放大器26、模数转换器28、29以及电生理信号提取模块30。ECG放大器27和EP信号放大器26将采集到的人体电生理信号放大，然后经模数转换器28、29转换成数字信号。电生理信号提取模块30连接模数转换器28、29，从数字信号中提取心腔内特定位置的电生理活动信息并输出至图形显示装置25，将电生理活动信息标记在心腔的三维图形模型上。The electrophysiological mapping device includes an ECG electrode 19 and a catheter electrode 14 for collecting human body electrophysiological signals, an ECG amplifier 27 connected to the ECG electrode 19, an EP signal amplifier 26 connected to the catheter electrode 14, and analog-to-digital converters 28, 29 And the electrophysiological signal extraction module 30. ECG amplifier 27 and EP signal amplifier 26 amplify the collected human electrophysiological signals, and then convert them into digital signals through analog-to-digital converters 28 and 29 . The electrophysiological signal extraction module 30 is connected to the analog-to-digital converters 28 and 29, extracts the electrophysiological activity information at a specific position in the heart chamber from the digital signal and outputs it to the graphic display device 25, and marks the electrophysiological activity information on the three-dimensional graphic model of the heart chamber superior.

放大器增益的精度对系统的定位性能有至关重要的影响，尤其是在多路的导管同时使用的定位系统中每个通道之间的放大参数匹配对于系统的精度非常重要。尽管本发明采用了简化、优质的模拟放大系统，由于电容、电阻等无源器件的制造误差以及环境温度的变化，放大器的通道之间的误差存在失调，即使采用优质元件这种误差也是无法忍受的。为此必须在数字系统中对这种误差进行补偿。本系统在定位放大器15上还设置自动校准装置，采用全自动补偿，可以在开机以及工作温度明显变化后不需要人工参与自动校准放大器系统。该装置包括温度探测器31、校准控制模块32、校准信号发生器33和幅度提取模块34。The accuracy of the amplifier gain has a crucial impact on the positioning performance of the system, especially in the positioning system where multiple catheters are used at the same time, the matching of the amplification parameters between each channel is very important for the accuracy of the system. Although the present invention adopts a simplified and high-quality analog amplification system, due to the manufacturing error of passive components such as capacitors and resistors and the change of ambient temperature, the error between the channels of the amplifier is misaligned, and this error is unbearable even if high-quality components are used. of. For this reason, this error must be compensated in the digital system. This system is also equipped with an automatic calibration device on the positioning amplifier 15, and adopts full-automatic compensation, which can automatically calibrate the amplifier system without manual participation after starting up and working temperature changes significantly. The device includes a temperature detector 31 , a calibration control module 32 , a calibration signal generator 33 and an amplitude extraction module 34 .

在温度探测器31探测到环境温度发生改变后，校准控制模块32启动校准信号发生器33，产生校准信号，并控制定位放大器15进入校准模式，此时所有定位放大器输入通路被切换到校准信号上。经过数十ms的时间后，定位放大器15和幅度提取模块34进入稳定状态，此时幅度提取模块34的输出为实际测得的携带误差信息的校准信号的强度Y。由于校准信号的幅度X是已知的，所以在校准控制模块32中计算出放大误差a＝Y/X，该误差结果被校准控制模块32保留。在退出校准模式后，以放大误差a作为补偿控制定位放大器15的放大增益，从而实现放大系统的校准。After the temperature detector 31 detects that the ambient temperature has changed, the calibration control module 32 starts the calibration signal generator 33 to generate a calibration signal, and controls the positioning amplifier 15 to enter the calibration mode. At this time, all positioning amplifier input channels are switched to the calibration signal. . After tens of ms, the positioning amplifier 15 and the amplitude extraction module 34 enter a stable state, and the output of the amplitude extraction module 34 is the actually measured strength Y of the calibration signal carrying error information. Since the amplitude X of the calibration signal is known, the amplification error a=Y/X is calculated in the calibration control module 32 , and the error result is retained by the calibration control module 32 . After exiting the calibration mode, the amplification gain of the positioning amplifier 15 is controlled with the amplification error a as compensation, so as to realize the calibration of the amplification system.

由于放大器系统是采用的高频窄带结构，所以放大器的可以在数十ms内进入稳定状态，从而使得校准工作可以在一个定位信号输出的采样周期内完成，这样一个快速的校准过程保证了正常信号的放大处理几乎不受影响，所以系统可以在温度探测装置检测到信号有明显变化时，如1摄氏度，自动启动校准过程，从而最终使放大器处在最佳的工作状态，并且不影响系统的正常工作。Since the amplifier system adopts a high-frequency narrow-band structure, the amplifier can enter a stable state within tens of milliseconds, so that the calibration work can be completed within a sampling period of the positioning signal output. Such a fast calibration process ensures normal signals. The amplification process is almost unaffected, so the system can automatically start the calibration process when the temperature detection device detects a significant change in the signal, such as 1 degree Celsius, so that the amplifier is in the best working state and does not affect the normal operation of the system Work.

另一方面，采用心内膜三维导航系统的导航方法如下：On the other hand, the navigation method using the endocardial three-dimensional navigation system is as follows:

(1)在体表上放置三对在空间位置上正交的激励电极，使用三个频率互不相同的低于10KHz的连续正弦波稳恒电流对三对激励电极加电，形成三维的低频稳恒电场。(1) Place three pairs of excitation electrodes orthogonal in spatial position on the body surface, and use three continuous sine wave constant currents with different frequencies below 10KHz to power the three pairs of excitation electrodes to form a three-dimensional low frequency steady electric field.

(2)导管电极采集导管在三维电场中的电场信号，经信号放大、模数转换以及数字解调后提取导管位置的电场信号强度信息。(2) The catheter electrode collects the electric field signal of the catheter in the three-dimensional electric field, and extracts the electric field signal intensity information of the catheter position after signal amplification, analog-to-digital conversion and digital demodulation.

(3)体表电极和ECG电极采集体表电场信号，经信号放大、模数转换后提取呼吸阻抗的变化信息。(3) Body surface electrodes and ECG electrodes collect body surface electric field signals, and extract changes in respiratory impedance after signal amplification and analog-to-digital conversion.

(4)从电场信号强度信息中剔除呼吸阻抗变化信息造成的误差，输出经校准的导管位置信号。(4) Eliminate the error caused by the respiratory impedance change information from the electric field signal strength information, and output the calibrated catheter position signal.

(5)采集包含心脏搏动周期信息的电生理信号，将经校准的导管位置信号与心脏外形的周期性变化进行同步处理。(5) Acquisition of electrophysiological signals including cardiac cycle information, and synchronously processing the calibrated catheter position signal and the periodic changes of the heart shape.

(6)根据同步处理后的导管位置信号建立心腔的三维模型。(6) Establishing a three-dimensional model of the heart chamber according to the synchronously processed catheter position signal.

应理解，上述实施例是提供给本领域普通技术人员来实现或使用本发明的，本领域普通技术人员可在不脱离本发明的发明思想的情况下，对上述实施例做出种种修改或变化，因而本发明的保护范围并不被上述实施例所限，而应该是符合权利要求书提到的创新性特征的最大范围。It should be understood that the above-mentioned embodiments are provided for those of ordinary skill in the art to implement or use the present invention, and those of ordinary skill in the art can make various modifications or changes to the above-mentioned embodiments without departing from the inventive idea of the present invention , so the scope of protection of the present invention is not limited by the above-mentioned embodiments, but should be the maximum scope consistent with the innovative features mentioned in the claims.