Method for monitoring operative pulmonary hemorrhage and pneumothorax in real time based on electrical impedance tomography

Abstract

The invention relates to a method for monitoring operative pulmonary hemorrhage and pneumothorax in real time based on electrical impedance tomography. The method comprises the following steps that 1, monitoring equipment is worn around a lung area; 2, constructing an image of the lung in real time by adopting electrical impedance tomography; 3, comparing the size of the electrical impedance tomography image with the size of the electrical impedance tomography image at the CT imaging time point in real time; when the image constructed by the electrical impedance tomography is close to the electrical impedance tomography image at the CT imaging time point, judging that the state of the lung of the patient at the moment is the same as the state during CT imaging; and 4, puncturing is carried out. According to the invention, the puncture accuracy can be improved.

Description

Technical Field

[0001] This invention relates to a method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography, and more particularly to a method for real-time monitoring of changes in lung volume and the status of surgical pulmonary hemorrhage and pneumothorax using electrical impedance tomography. Background Technology

[0002] CT-guided percutaneous lung and liver puncture is commonly used for biopsies, drainage, and interventional treatments. The procedure mainly involves determining the size, depth, puncture point, and angle of the lesion based on CT images. The doctor then performs the puncture based on the data provided by the CT images and their experience. However, the patient's respiratory movements can cause displacement of the lesion in the lung or liver (up to 5-10 cm), making it difficult for the doctor to accurately puncture the lesion (especially smaller lesions). Furthermore, due to differences in individual experience, the doctor needs to repeatedly perform puncture-CT scan confirmation-adjustment-CT scan confirmation-adjustment-CT scan confirmation, which greatly increases the risk of complications such as pulmonary hemorrhage and pneumothorax, and also exposes the patient to more X-ray radiation.

[0003] Currently, an increasing number of optical navigation, electromagnetic navigation, laser navigation, and puncture robots are being used to assist percutaneous punctures. These technologies use patient CT scan images as a basis to determine the puncture path through three-dimensional reconstruction. However, none of these puncture navigation devices can currently monitor the occurrence of pulmonary hemorrhage and pneumothorax during the puncture process in real time. Because the tidal volume of each inhalation varies from patient to patient, the gas volume in the lungs also varies. Especially when the patient is in a prone position, it is difficult to monitor changes in lung volume on the back surface, which can easily lead to puncture errors and puncture failure. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this invention is to provide a method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography includes the following steps: Step 1: Wear the monitoring device around the lung area; Step 2: Construct lung images in real time using electrical impedance tomography; Step 3: Compare the size of the impedance tomographic image with the size at the same CT imaging time point in real time; When the image constructed by electrical impedance tomography is close to the electrical impedance tomography image at the same time point as the CT imaging, it is determined that the condition of the patient's lungs at this time is the same as that at the time of CT imaging. Step 4: Perform the puncture.

[0006] Preferably, in the method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography, the width of the monitoring device is about 4cm, the width of the monitoring plane is ≥4cm, and the monitoring device with electrodes is arranged around the chest cavity to form an electrode plane, with the electrodes occupying 20%~30% of the total lung volume.

[0007] Preferably, in the method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography, the electrode distribution on the patient includes partial coverage and full coverage.

[0008] Preferably, in the method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography, the algorithm for image-based formation in step 2 is as follows: Functional imaging techniques based on bioelectrical impedance analysis utilize Ohm's law, R=U / I, to determine the distribution of thoracic bioelectrical impedance between the injected electrode pair and the measured electrode pair by using known measured values ​​of applied current and voltage. During lung inflation and deflation, the amount of gas also leads to differences in resistance. Then, by analyzing impedance, image reconstruction, and image processing, a relative value of lung volume equivalent to a baseline is obtained.

[0009] Preferably, the method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography displays images constructed by electrical impedance tomography in real time.

[0010] Preferably, in the method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography, when the electrical impedance tomography image at the same time point as the CT imaging time point is close to 70%, it is determined that the condition of the patient's lungs at this time is the same as the condition at the time of CT imaging.

[0011] Preferably, in the method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography, if the condition of the patient's lungs is the same as that during CT imaging, then it is the optimal time window for puncture in step 4.

[0012] Preferably, in the method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography, an alarm is triggered in step 4 if the puncture time window is missed.

[0013] Preferably, the method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography determines the status of surgical pulmonary hemorrhage and pneumothorax based on the image comparison in step 3.

[0014] Preferably, the method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography includes image reconstruction and image processing. Step 21: Data Acquisition 1) Several electrodes are arranged in a ring on the surface of the patient's chest, and each electrode is connected to the multiple acquisition module of the electrical impedance tomography system through wires. 2) According to the set excitation mode, select a number of electrode pairs as current injection terminals and the remaining electrodes as voltage measurement terminals. 3) Multi-frequency excitation is used to distinguish the impedance characteristics of blood and gas; 4) Synchronously acquire the voltage distribution signal under each set of excitations, and record the injected current amplitude, phase, and sampling timestamp. Step 22: Impedance measurement, 1) Demodulate the amplitude and phase of the acquired multi-channel voltage signals to obtain the complex impedance distribution matrix between each electrode. 2) Using models to estimate impedance changes, including: Complex impedance model: Where R is the real part of the impedance and X is the imaginary part; Differential impedance variation model: ΔZ(t) = Z(t) − Zref in, This is the reference impedance used during CT imaging; Step 23: Imaging and Reconstruction By comparing the sensitivity matrix S of each pixel in the reference model, the conductivity change of each pixel is calculated, and the corresponding image is generated. Δσ=S−1.ΔV Where ΔV is the displacement increment (the increment of position change) and Δσ is the strain increment (the increment of the degree of deformation).

[0015] Preferably, in the method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography, when the electrical impedance tomography image at the same time point as the CT imaging time point is close to 70%, it is determined that the condition of the patient's lungs at this time is the same as the condition at the time of CT imaging. The method of judgment is as follows: In step 3, if the image constructed by electrical impedance tomography is close to the electrical impedance tomography image at the same time point as the CT imaging, then it is determined that the condition of the patient's lungs at this time is the same as the condition at the time of CT imaging. The method of judgment is as follows: 1) Image registration and normalization Ensure real-time acquisition of electrical impedance tomography images Reference impedance tomographic images at CT imaging time points Direct comparison is possible, and spatial and brightness normalization can be performed. 2) Impedance difference calculation In the registered coordinate system, calculate the average impedance difference between the two images. :when hour, The custom threshold indicates that the overall electrical impedance distribution is similar; 3) Structural similarity determination To further assess the consistency of lung structural regions, a structural similarity index (SSIM) is introduced: SSIM hour, A custom threshold is used to assume that the structural distributions of the two images are consistent.

[0016] By means of the above-described solution, the present invention has at least the following advantages: This invention utilizes electrical impedance tomography (EIT) technology to monitor changes in lung volume in real time, providing an optimal puncture time window for lung or liver punctures guided by artificial, optical, electromagnetic, or robotic methods, thereby improving puncture accuracy.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of the present invention; Figure 2a This is a schematic diagram of the electrode of the present invention partially covering the patient during installation; Figure 2b This is a schematic diagram of the electrode fully covering the patient during installation according to the present invention; Figure 3 This is a schematic diagram of the electrode current direction of the present invention; Figure 4 This is a flowchart of the image reconstruction and image processing of the present invention; Figure 5 This is a schematic diagram of the ROI partitioning for local lung ventilation imaging of the present invention; Figure 6 This is a schematic diagram of the local lung ventilation imaging—gravity gradient stratification of the present invention. Figure 7a This is a schematic diagram of lung recruitment before lung re-expansion in local lung ventilation imaging of the present invention; Figure 7bThis is a schematic diagram of lung recruitment in local lung ventilation imaging according to the present invention; Figure 7c This is a schematic diagram of lung recruitment after local lung ventilation imaging according to the present invention; Figure 8 This is a schematic diagram illustrating the impedance variation trend of the present invention; Figure 9 This is a schematic diagram of the lung compliance of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] Example like Figures 1 to 4 As shown, a method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography includes the following steps: Step 1: Wear the monitoring device around the lung area; Step 2: Construct lung images in real time using electrical impedance tomography; Step 3: Compare the size of the impedance tomographic image with the size at the same CT imaging time point in real time; When the image constructed by electrical impedance tomography is close to the electrical impedance tomography image at the same time point as the CT imaging, it is determined that the condition of the patient's lungs at this time is the same as that at the time of CT imaging. Step 4: Perform the puncture.

[0023] In this embodiment, the width of the monitoring device is about 4cm, the width of the monitoring plane is ≥4cm, and the monitoring device with electrodes is arranged around the chest cavity to form an electrode plane, with the electrodes occupying 20% ​​to 30% of the total lung volume.

[0024] The electrode plane is formed around the chest cavity, accounting for 20% to 30% of the total lung volume. The recommended position for the chest band is between the 4th and 5th ribs.

[0025] The higher the placement position, the smaller the monitored lung volume, and the more difficult it is to distinguish between the left and right lungs; The lower the position, the closer it is to the diaphragm, and the more likely it is to produce artifacts.

[0026] In this invention, the distribution of electrodes on the patient includes partial coverage and full coverage.

[0027] The algorithm for image correspondence in step 2 of this invention is based on functional imaging technology using bioelectrical impedance analysis. It applies Ohm's law, R=U / I, and determines the distribution of thoracic bioelectrical impedance between the injected electrode pair and the measured electrode pair by using known measured values ​​of applied current and voltage. During the inflation and deflation of the lungs, the amount of gas also leads to a difference in resistance. Then, by analyzing the impedance, image reconstruction, and image processing, a relative value of the lung volume equivalent to a baseline is obtained.

[0028] The specific image reconstruction and image processing are as follows: Step 21: Data Acquisition 1) Several electrodes are arranged in a ring on the surface of the patient's chest, and each electrode is connected to the multiple acquisition module of the electrical impedance tomography system through wires. 2) According to the set excitation mode, select a number of electrode pairs as current injection terminals and the remaining electrodes as voltage measurement terminals. 3) Multi-frequency excitation is used to distinguish the impedance characteristics of blood and gas; 4) Synchronously acquire the voltage distribution signal under each set of excitations, and record the injected current amplitude, phase, and sampling timestamp. Step 22: Impedance measurement, 1) Demodulate the amplitude and phase of the acquired multi-channel voltage signals to obtain the complex impedance distribution matrix between each electrode. 2) Using models to estimate impedance changes, including: Complex impedance model: Where R is the real part of the impedance and X is the imaginary part; Differential impedance variation model: ΔZ(t) = Z(t) − Zref in, This is the reference impedance used during CT imaging; Step 23: Imaging and Reconstruction By comparing the sensitivity matrix S of each pixel in the reference model, the conductivity change of each pixel is calculated, and the corresponding image is generated. Δσ=S−1.ΔV Where ΔV is the displacement increment (the increment of position change) and Δσ is the strain increment (the increment of the degree of deformation).

[0029] Preferably, in the method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography, when the electrical impedance tomography image at the same time point as the CT imaging time point is close to 70%, it is determined that the condition of the patient's lungs at this time is the same as the condition at the time of CT imaging. The method of judgment is as follows: In step 3, if the image constructed by electrical impedance tomography is close to the electrical impedance tomography image at the same time point as the CT imaging, then it is determined that the condition of the patient's lungs at this time is the same as the condition at the time of CT imaging. The method of judgment is as follows: 1) Image registration and normalization Ensure real-time acquisition of electrical impedance tomography images Reference impedance tomographic images at CT imaging time points Direct comparison is possible, and spatial and brightness normalization can be performed. 2) Impedance difference calculation In the registered coordinate system, calculate the average impedance difference between the two images. :when hour, The custom threshold indicates that the overall electrical impedance distribution is similar; 3) Structural similarity determination To further assess the consistency of lung structural regions, a structural similarity index (SSIM) is introduced: SSIM hour, A custom threshold is used to assume that the structural distributions of the two images are consistent.

[0030] When the electrical impedance tomography image at the same time point as the CT imaging is close to or exceeds 70%, it is determined that the condition of the patient's lungs at this time is the same as that at the time of CT imaging. At the same time, if the condition of the patient's lungs is the same as that at the time of CT imaging, it is the optimal time window for puncture in step 4.

[0031] This invention displays images constructed using electrical impedance tomography in real time.

[0032] In step 4 of this invention, an alarm will be triggered if the puncture time window is missed.

[0033] In this invention, the status of surgical pulmonary hemorrhage and pneumothorax is determined based on the image comparison in step 3.

[0034] Example 1 The actual clinical operation based on the operating method of the embodiment is as follows: like Figure 5 As shown, regional lung ventilation imaging – ROI partitioning In actual clinical applications, EIT lung ventilation images can be artificially divided into several parallel regions or quadrants, i.e., customized regions of interest (ROIs). When ROI is partitioned by quadrant: Normally, the right lung (3 lobes) is ventilated slightly more than the left lung (2 lobes); Among them, when comparing the difference in ventilation between the left and right lungs, or when the lesion only affects one lung, the reference range is: right side: 50-55%, left side: 45-50%.

[0035] like Figure 6 As shown, local lung ventilation imaging—gravity gradient stratification. When ROIs are stratified according to gravity gradients: Under normal circumstances, the ratio of the ventral to the dorsal side is close to 1:1. Depending on the patient's position and the location of the electrode straps, lesions may be present in both lung lobes, especially those that change with gravity gradients (e.g., ARDS). The following markings can be used as a reference: ventral 10-15%; ventral mid-region: 35-40%; dorsal 10-15%; dorsal mid-region: 35-40%.

[0036] like Figure 7a , 7b As shown in Figure 7c, localized lung ventilation imaging—lung recruitment. Determine the current state based on the parameters indicated in the attached diagram (the corresponding question can be found using the following references), including... Before lung re-expansion, as Figure 7a , ROI1: 28%, ROI2: 50%, ROI3: 15%, ROI4: 7%; During lung re-expansion, as Figure 7b , ROI1: 4%, ROI2: 30%, ROI3: 51%, ROI4: 15%; After lung re-expansion, such as Figure 7c , ROI1: 10%, ROI2: 47%, ROI3: 32%, ROI4: 11%.

[0037] like Figure 8 As shown, the present invention uses EIT to provide an end-expiratory lung impedance (EELI) trend view, which can compare the gas distribution in different respiratory cycles. The EELI trend view shows the change in end-expiratory lung volume in the electrode plane, providing information on the change in end-expiratory lung impedance caused by the change in end-expiratory lung volume.

[0038] Based on the EIT trend view, such as Figure 9As shown, EIT can reconstruct lung compliance images through impedance differential, assess regional lung function, aid in clinical diagnosis and treatment, and even prevent atelectasis and overinflation.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of this application, it should be noted that the terms "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0041] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or vertical, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0042] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography, characterized in that, Includes the following steps: Step 1: Wear the monitoring device around the lung area; Step 2: Construct lung images in real time using electrical impedance tomography; Step 3: Compare the size of the impedance tomographic image with the size at the same CT imaging time point in real time; When the image constructed by electrical impedance tomography is close to the electrical impedance tomography image at the same time point as the CT imaging, it is determined that the condition of the patient's lungs at this time is the same as that at the time of CT imaging. Step 4: Perform the puncture.

2. The method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography according to claim 1, characterized in that: The monitoring device is approximately 4cm wide, and the monitoring plane is ≥4cm wide. The monitoring device with electrodes is arranged around the chest cavity to form an electrode plane, with the electrodes occupying 20% ​​to 30% of the total lung volume.

3. The method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography according to claim 1, characterized in that: Electrode distribution in the patient can be either partial or full coverage.

4. The method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography according to claim 1, characterized in that: The algorithm for image correspondence in step 2: Functional imaging techniques based on bioelectrical impedance analysis utilize Ohm's law, R=U / I, to determine the distribution of thoracic bioelectrical impedance between the injected electrode pair and the measured electrode pair by using known measured values ​​of applied current and voltage. During lung inflation and deflation, the amount of gas also leads to differences in resistance. Then, by analyzing impedance, image reconstruction, and image processing, a relative value of lung volume equivalent to a baseline is obtained.

5. The method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography according to claim 4, characterized in that: Image reconstruction and image processing Step 21: Data Acquisition 1) Several electrodes are arranged in a ring on the surface of the patient's chest, and each electrode is connected to the multiple acquisition module of the electrical impedance tomography system through wires. 2) According to the set excitation mode, select a number of electrode pairs as current injection terminals and the remaining electrodes as voltage measurement terminals. 3) Multi-frequency excitation is used to distinguish the impedance characteristics of blood and gas; 4) Synchronously acquire the voltage distribution signal under each set of excitations, and record the injected current amplitude, phase, and sampling timestamp. Step 22: Impedance measurement, 1) Demodulate the amplitude and phase of the acquired multi-channel voltage signals to obtain the complex impedance distribution matrix between each electrode. 2) Using models to estimate impedance changes, including: Complex impedance model: Where R is the real part of the impedance and X is the imaginary part; Differential impedance variation model: ΔZ(t)=Z(t)−Zref in, This is the reference impedance used during CT imaging; Step 23: Imaging and Reconstruction By comparing the sensitivity matrix S of each pixel in the reference model, the conductivity change of each pixel is calculated, and the corresponding image is generated. Δσ=S−1.ΔV Where ΔV is the displacement increment (the increment of position change) and Δσ is the strain increment (the increment of the degree of deformation).

6. The method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography according to claim 1, characterized in that: Real-time display of images constructed by electrical impedance tomography.

7. The method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography according to claim 6, characterized in that: When the electrical impedance tomography image at the same time point as the CT imaging is close to or exceeds 70%, it is determined that the condition of the patient's lungs at this time is the same as that at the time of CT imaging. The method of judgment is as follows: In step 3, if the image constructed by electrical impedance tomography is close to the electrical impedance tomography image at the same time point as the CT imaging, then it is determined that the condition of the patient's lungs at this time is the same as the condition at the time of CT imaging. The method of judgment is as follows: 1) Image registration and normalization Ensure real-time acquisition of electrical impedance tomography images Reference impedance tomographic images at CT imaging time points Direct comparison is possible, and spatial and brightness normalization can be performed. 2) Impedance difference calculation In the registered coordinate system, calculate the average impedance difference between the two images. :when hour, The custom threshold indicates that the overall electrical impedance distribution is similar; 3) Structural similarity determination To further assess the consistency of lung structural regions, a structural similarity index (SSIM) is introduced: SSIM hour, A custom threshold is used to assume that the structural distributions of the two images are consistent.

8. A method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography according to claim 6, characterized in that: If the condition of the patient's lungs is the same as that observed during CT imaging, then this is the optimal time window for puncture in step 4.

9. The method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography according to claim 1, characterized in that: In step 4, an alarm will sound if the puncture time window is missed.

10. A method for real-time monitoring of surgical pulmonary hemorrhage and pneumothorax based on electrical impedance tomography according to claim 1, characterized in that: Based on the image comparison in step 3, determine the status of surgical pulmonary hemorrhage and pneumothorax.

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