CN111449657B

CN111449657B - Image Monitoring System and Pulmonary Embolism Diagnosis System

Info

Publication number: CN111449657B
Application number: CN202010296273.0A
Authority: CN
Inventors: 何怀武; 隆云; 招展奇; 池熠; 袁思依
Original assignee: Peking Union Medical College Hospital Chinese Academy of Medical Sciences
Current assignee: Peking Union Medical College Hospital Chinese Academy of Medical Sciences
Priority date: 2020-04-15
Filing date: 2020-04-15
Publication date: 2021-05-18
Anticipated expiration: 2040-04-15
Also published as: CN111449657A

Abstract

The invention discloses a bedside lung ventilation-blood flow perfusion electrical impedance tomography imaging method based on saline contrast. In addition, the present invention also discloses an image monitoring device, an image monitoring system and a pulmonary embolism diagnosis system based on the above method. The method of the invention improves the imaging quality of blood perfusion, and calculates the dead space ventilation %, the intrapulmonary shunt %, and the regional ventilation-blood flow matching %, which is more practical. The method of the present invention can diagnose pulmonary embolism with a sensitivity of 90.9% and a specificity of 98.6%, and has high clinical application value.

Description

Image monitoring system and pulmonary embolism diagnosis system

Technical Field

The invention belongs to the field of clinical medicine, and particularly relates to a bedside pulmonary ventilation-blood perfusion electrical impedance tomography method based on saline contrast.

Background

Electrical Impedance Tomography (EIT) is a non-invasive imaging technique used to study and detect regional lung ventilation and perfusion (blood flow) in humans and animals. In contrast to conventional methods, EIT does not require the patient to breathe through a tube or sensor, does not apply ionizing X-rays, and can be used for long periods of time, such as 24 hours or even longer. Thus, EIT can be used continuously and is therefore suitable for real-time and long-term monitoring of the effect of therapy. EIT was first used in 1983 to monitor respiratory function and maintain the only bedside method that allows continuous, non-invasive detection of regional changes in lung volume, blood flow, and heart activity. More details of this technology can be found in "electric impedance biology" by Costa e.l., Lima r.g., and Amato m.b.in Cur oper Crit Care, feb.2009,15(1), p.18-24.

In EIT, as disclosed in US patent US5626146, a plurality of electrodes, typically from 8 to 32, are arranged on the surface of the body to be examined. The control unit ensures that an electrical signal, e.g. an electrical current, is applied to one or more pairs of electrodes on the skin to create an electric field, which in turn is detected by the other electrodes. The electrodes used to apply the current are referred to as "current injection electrodes", although one of them may serve as a reference potential, such as ground. Typically, 3 to 10mARMS are injected in the frequency range of 0.1-1000 kHz. With the remaining electrodes, the resulting voltage is detected (forming an "EIT data vector" or "scan frame") and then used to estimate the distribution of electrical impedance in the body. Specific algorithms are developed to convert a set of voltages into an image.

At present, the bedside pulmonary vessel perfusion imaging quality based on an Electrical Impedance Tomography (EIT) is poor, and the bedside pulmonary vessel perfusion imaging quality is interfered by resistance signals such as heart pulsation, pulmonary vessel pulsation and the like, and the clinical applicability is poor. In order to improve the imaging quality, a saline angiography technology electrical impedance imaging technology method is researched and developed, saline is injected through a central venous catheter, apnea is performed at the same time, the change of thoracic resistance signals is collected, a local resistance-time change curve of the saline angiography is established, but the types of resistance-time curve analysis methods are more, the saline reaching to the right atrium is identified in the saline injection process, the resistance signals are reduced and easy to interfere, the imaging analysis is influenced, and the accurate first arrival time lung time point of the saline is difficult to obtain.

In the bedside pulmonary blood perfusion imaging analysis, the distribution percentage of ventilation and blood flow is mostly concentrated by the current electrical impedance technology, belongs to semi-quantitative evaluation, and is technically difficult to enter the ventilation dead space and the equivalent calculation of intrapulmonary circulation.

The method aims to solve the technical problem of bedside electrical impedance pulmonary perfusion imaging, and improves the accuracy and application value.

Disclosure of Invention

Technical problem

One of the purposes of the invention is to provide a bedside electrical impedance tomography method based on saline contrast pulmonary ventilation-blood flow perfusion.

It is another object of the present invention to provide an image monitoring apparatus.

It is a further object of the present invention to provide an image monitoring system.

It is a fourth object of the present invention to provide a method and a system for diagnosing pulmonary embolism.

Technical scheme

According to one aspect of the invention, a bedside saline contrast-based pulmonary ventilation-perfusion electrical impedance tomography method is provided. The method comprises the following steps:

(1) breath hold tests, requiring a minimum of over 8 seconds;

(2) injecting saline water to perform pulmonary blood perfusion radiography, and continuously acquiring the change of electrical impedance signals of the chest;

(3) and performing off-line analysis on the resistance signal data.

The specific operation of the step (1) is as follows: breath holding test, requiring a minimum of more than 8 seconds (when the ventilator is mechanically ventilated, the breath holding button is pressed for 10s for expiration or inspiration; the patient orders to hold breath for 8 seconds for spontaneous breathing); after the breath holding test is passed, an EIT examination can be performed by a saline angiography.

The concentration of the injection saline of the present invention was 10%, and the injection amount was 10 ml.

The specific operation of the step (2) is as follows: connecting a test subject with a pulmonary electrical impedance monitoring instrument, preparing 10% NaCl 10ml, and confirming that the test subject establishes a central venous catheter; after breath holding starts, injecting 10% NaCl 10ml from a central venous catheter into the body to carry out pulmonary blood perfusion radiography; changes in thoracic electrical impedance signals were continuously acquired beginning 2 minutes prior to the saline injection.

The step (3) of performing off-line analysis on the resistance signal data comprises the following steps:

a. constructing a lung blood flow perfusion image;

b. constructing a lung ventilation image;

c. a lung ventilation/blood flow distribution image is constructed.

The specific operation of constructing the pulmonary blood flow perfusion image in the step a is as follows: the whole resistance curve begins to decline as the starting point (T0) when saline enters the body during breath holding, as the starting point (T1) when saline enters the pulmonary blood vessel after a cardiac cycle, and the lowest point of the whole resistance is the end point (T2) when saline passes through the pulmonary blood vessel, and the resistance curve of the time period of T0-T1 reflects that saline enters the right heart and does not reflect pulmonary blood vessel perfusion, and the curve of the time period is not adopted in the analysis for reducing interference; resistance-time change curves (slope fits) for the various lung regions for the T1-T2 time periods were used for construction.

The specific operation of constructing the lung ventilation image in the step b is as follows: lung ventilation image construction was performed by changes in lung resistance over at least 5 consecutive respiratory cycles within 1 minute prior to injection.

The specific operation of constructing the lung ventilation/blood flow distribution image in step c is as follows: the lung ventilation image and the lung blood flow perfusion image take 20% of the maximum pixel points as a threshold value to construct a lung ventilation/blood flow distribution image.

According to another aspect of the present invention, there is provided an image monitoring apparatus including a data receiver, an image processor, and a controller.

The data receiver is responsible for receiving lung ventilation impedance data and lung blood perfusion impedance data measured by the lung electrical impedance monitoring instrument.

The image processor is responsible for generating a lung ventilation image and a lung blood perfusion image from the lung ventilation impedance data and the lung blood perfusion impedance data. The image processor generates an image from the impedance data according to the method described above.

The controller is responsible for controlling display of at least one of a lung ventilation image, a lung blood perfusion image, according to a screen mode and a measurement site.

The controller may include an image and waveform output control module, an impedance measurement control module, and an information determination and transmission module.

The image and waveform output control module may be configured to control display of at least one of a lung ventilation image, a lung blood flow perfusion impedance image, and a lung ventilation/blood flow distribution image according to a preset screen mode or a measurement site of a subject desired to be monitored.

The measurement site may refer to a site that is more accurately monitored with respect to the state of at least one of the lungs, heart of the subject.

The screen mode may include a plurality of screen regions divided based on a certain pathological state of the subject to display at least one of a lung ventilation image, a lung blood flow perfusion impedance image, and a lung ventilation/blood flow distribution image.

The impedance measurement control module may be configured to control the electrical impedance monitoring instrument to measure lung ventilation impedance data, lung blood flow perfusion impedance data at the chest of the subject.

The information determination and transmission module may be configured to control features implemented by the data receiver and the image processor and transmit the received lung ventilation impedance data, lung blood flow perfusion impedance data, to the image processor to enable the lung ventilation impedance data, lung blood flow perfusion impedance data to be generated as an image.

Moreover, the information determination and transmission module may be configured to control transmission of the received lung ventilation impedance data, lung blood flow perfusion impedance data, and at least one of the generated lung ventilation impedance image, lung blood flow perfusion impedance image to the outside.

According to a further aspect of the present invention, there is provided an image monitoring system comprising the image monitoring apparatus as described above.

Further, the system may further comprise a pulmonary electrical impedance monitoring instrument. The pulmonary electrical impedance monitoring instrument is responsible for measuring pulmonary ventilation impedance data and pulmonary blood perfusion impedance data.

According to a further aspect of the invention there is provided a method of diagnosing pulmonary embolism, the method comprising constructing a lung ventilation/blood flow distribution image using the method described above, calculating the percentage of dead space ventilation% (regions ventilated only but not perfused by blood flow as a percentage of the total region), and diagnosing pulmonary embolism when the% dead space ventilation > 30.37%.

According to a further aspect of the invention, there is provided a pulmonary embolism diagnosis system comprising a diagnosis device which operates the diagnosis method as described above.

Preferably, the system further comprises an image monitoring device as described above.

More preferably, the system further comprises a pulmonary electrical impedance monitoring instrument.

Pulmonary embolism refers to clinical and pathophysiological syndromes of pulmonary circulatory disturbance caused by various emboli entering pulmonary circulation to block pulmonary artery or other branches, and comprises pulmonary thromboembolism, fatty embolism syndrome, amniotic fluid embolism, air embolism and the like.

Technical effects

The method of the invention removes the resistance signal of a cardiac cycle by ventilation, effectively reduces the interference of the heart, reliably identifies the time node when the saline contrast agent first reaches the lung area, and can maintain the original lung area as much as possible.

The method of the invention provides pre-test breath-holding evaluation, and improves the efficiency of blood flow distribution evaluation.

According to the method, a 20% threshold value is determined through screening, the quality of blood perfusion imaging is improved, and therefore the ventilation of dead space, the intrapulmonary bypass and regional ventilation-blood flow matching% (V/Q Macth%) are calculated, and the method is more practical.

The method of the invention can be used for diagnosing the pulmonary embolism, the sensitivity is 90.9%, the specificity is 98.6%, and the method has high clinical application value.

Drawings

FIG. 1 shows a graph of electrical impedance versus time;

fig. 2 shows a right heart image and a pulmonary blood flow perfusion image, where a: a right heart image; b: lung blood flow perfusion images;

FIG. 3 shows a ROC plot;

fig. 4 shows an image of the lungs of a pulmonary embolism patient a, where a: pulmonary blood vessel CT radiography; b: a lung ventilation image; c: lung blood flow perfusion images; d: lung ventilation/blood flow distribution images;

fig. 5 shows an image of the lungs of a hemothorax patient B, where a: carrying out lung CT radiography; b: a lung ventilation image; c: lung blood flow perfusion images; d: lung ventilation/blood flow distribution images.

Detailed Description

Before the present embodiments are further described, it is to be understood that the scope of the invention is not limited to the particular embodiments described below; it is also to be understood that the terminology used in the examples is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. Test methods in which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under conditions recommended by the respective manufacturers.

Example Lung ventilation/blood flow Profile construction and Joint analysis

Measurement case and data acquisition

The study was conducted by the ethical committee of this unit. The standard of group entry is the clinical diagnosis of respiratory failure patients, and central venous catheter injection drug therapy has been established. Exclusion of standard chest deformities or monitoring of electrical impedance presents contraindications (local skin lesions).

Patient information: 33 women, 50 men, average age 62 years, most of whom were respiratory failure patients.

EIT raw data from PulmoVista 500(

L ü beck, Germany), an EIT electrode strip containing 16 sensing electrodes was placed between the fourth to sixth ribs of the patient and a reference electrode was placed on the abdomen. The current excitation pattern is an adjacent excitation pattern, and a single EIT image contains 32 × 32 pixels and contains 20 frames of images per second. Subsequent processing of the EIT images was based on MATLAB R2015b (Mathworks, Natick, Massachusetts, USA).

Firstly, a breath holding test requires more than 8 seconds at least (when the breathing machine mechanically ventilates, the breathing machine is properly calmed, the breathing machine is adjusted to be a complete control ventilation mode, and an expiration or inspiration hold key is pressed for 10 s; the patient self-lives breath holds for 8 seconds); after the breath holding test is passed, an EIT examination can be performed by a saline angiography.

The patient was then connected to a pulmonary electrical impedance monitoring instrument, 10ml of 10% NaCl was prepared, and it was confirmed that the patient had established a central venous catheter (either the internal jugular vein or the subclavian vein catheter). 3) Saline injection: generally requiring 2 operators to complete the operation together, wherein one operator sends a command of injecting saline while confirming that the EIT machine works normally and starting breath holding of the patient; another operator receives confirmation instructions and quickly injects 10% NaCL 10ml into the patient from the central venous catheter; the EIT monitor starts a recording mode during the whole operation period, the thoracic electrical impedance signal data are continuously acquired at the beginning of 2 minutes before the saline injection, the whole process is required to last for at least 5 minutes, and the process that the pulmonary resistance is reduced due to the saline injection during the breath-holding period is completely recorded. Thirdly, the resistance signal data is analyzed off line, and the analysis steps are as follows:

1. the whole resistance curve begins to decline as the starting point (T0) that saline enters into the body during breath holding, as the starting point (T1) that saline enters into the pulmonary vessel after a movement cycle, the lowest point of the whole resistance is the end point (T2) that saline passes through the pulmonary vessel, the resistance curve of T0-T1 time interval reflects that saline enters into the right heart, does not reflect pulmonary vessel perfusion, in order to reduce interference, the curve of the time interval is not adopted in the analysis; applying resistance-time variation curves (slope fit) of the respective lung regions for the T1-T2 time periods for lung blood flow perfusion image construction (fig. 1 and 2); the lung blood flow perfusion image was constructed as follows:

(1) calculating the perfusion volume of the ith pixel point_i(t)＝a_it + b, time t, time period of the regional resistance-time curve for the acceptance analysis, a_iFitting the slope of the curve, wherein the local slope can reflect the size of the perfusion volume;

(2) lung perfusion image distribution map formula

Wherein a is_gIs asThe relative lung perfusion amount of the g-th pixel point, a is the slope of a fitting straight line of the regional resistance; and N is the total number of pixel points in the lung area. The perfusion amount of each pixel accounts for the percentage of the total perfusion amount of the obtained relative lung perfusion distribution image;

2. constructing a lung ventilation image by lung resistance changes for at least 5 consecutive respiratory cycles within 1 minute prior to injection; the lung ventilation image is constructed as follows:

wherein V_iThe total pixel point of the ventilation graph is N, and the number of the included respiration periods is N; delta Z_iIns is the relative resistance change in inspiration, Δ Z_iExp is the expiratory relative resistance change;

3. through the optimal selection of 0-40% threshold, the lung ventilation image and the lung blood flow image are determined, and 20% of the maximum pixel points are used as the threshold to construct a lung ventilation/blood flow distribution image; the specific formula is as follows:

V_k＞20％×max(V_K), K∈[1,1024]

k is defined as a pixel with ventilation locally,

P_g＞20％×max(P_G), G∈[1,1024]

g is defined as a pixel point with perfusion locally;

4. and (3) obtaining ventilation-blood flow combined parameters by performing area fitting analysis on the lung ventilation map and blood flow perfusion distribution:

dead space ventilation%: the percentage of total area that is only ventilated but not perfused by blood flow;

intrapulmonary bypass%: the percentage of total area that is only perfused by blood flow but not ventilated;

regional ventilation-blood flow matching% (V/Q mach%): the percentage of total area where there is both blood perfusion and ventilation.

The research proves that the method can effectively identify the abnormality of the blood flow ventilation distribution in the lung of the respiratory failure patients, 11 patients are diagnosed with acute pulmonary embolism in 83 cases of severe patients, and 72 patients are not diagnosed with pulmonary embolism clinically. The application of the related technical parameters of the invention, namely the percent of dead space ventilation is more than 30.37, the sensitivity is 90.9 percent, the specificity is 98.6 percent, and the diagnostic efficiency is obviously superior to that of the traditional serological index DD dimer. The ROC curve is shown in fig. 3.

Typical cases are:

pulmonary embolism patient a, basic information: in men, 59, acute respiratory failure after lung cancer surgery, and acute pulmonary embolism is diagnosed.

Pulmonary angiography (fig. 4A) suggested pulmonary embolism, thrombus visible in the right pulmonary artery, normal lung ventilation image (fig. 4B), decreased lung blood flow in the right side as seen in the lung blood perfusion image (fig. 4C), increased dead space ventilation in the right side as seen in the lung ventilation/blood flow distribution image (fig. 4D), consistent with clinical diagnosis.

Hemothorax patient B, basic information: in men, 40, respiratory failure, bleeding from ruptured intercostal arteries in the chest resulting in hemothorax.

Lung CT contrast (fig. 5A) suggests a lower left thoracic hemothorax, lung ventilation image (fig. 5B) suggests a lower left ventilation deficiency, lung blood perfusion image (fig. 5C) suggests a lower left ventilation deficiency, and lung ventilation/blood distribution image (fig. 5D) suggests a lower left ventilation/blood flow deficiency, consistent with clinical diagnosis.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and it should be understood by those skilled in the art that various modifications or changes can be made by those skilled in the art without inventive efforts based on the technical solutions of the present invention.

Claims

1. An image monitoring device, characterized in that the device comprises an image processor, and the image processor is responsible for generating a lung ventilation image and a lung blood perfusion image from lung ventilation impedance data and lung blood perfusion impedance data; the image The processor generates an image from the impedance data according to the following method, the method comprising the steps of:

(1) Breath-hold test, which requires at least 8 seconds;

(2) Pulmonary blood perfusion angiography was performed by injecting saline, and the changes of the electrical impedance signal of the chest were continuously collected;

(3) Offline analysis of resistance signal data, including:

a. Construct pulmonary blood perfusion image;

b. Construct lung ventilation images;

c. Construct pulmonary ventilation/blood flow distribution images;

The operation of step a includes: the overall resistance curve begins to decrease during breath-holding as the starting point of saline entering the body, named T0, after one cardiac cycle, it is the starting point of saline entering the pulmonary blood vessels, named T1, and the lowest point of the overall resistance is taken as the saline passing through the pulmonary blood vessels The end point, named T2, the resistance curve of the T0-T1 time period reflects the saline entering the right heart; the resistance-time change curve of each lung region in the T1-T2 time period is used to construct the pulmonary blood perfusion image by slope fitting.

2. device according to claim 1, is characterized in that, the concrete operation of step (1) is as follows: breath-hold test, requires at least more than 8 seconds: during mechanical ventilation of ventilator, press exhalation or inspiratory breath-hold button 10s; Spontaneously breathing patients were instructed to hold their breath for 8 seconds; after the breath-hold test was passed, saline contrast EIT examination was performed.

3. The device according to claim 1 or 2, wherein the concentration of the injected saline is 10%, and the injection volume is 10 ml.

4. device according to claim 1, is characterized in that, the concrete operation of step (2) is as follows: experimenter connects pulmonary electrical impedance monitoring instrument, prepares 10%NaCl 10ml, confirms that patient has established central venous catheter; After the start, 10ml of 10% NaCl was injected from the central venous catheter into the body for pulmonary perfusion angiography; the changes of the electrical impedance signal of the chest were continuously collected 2 minutes before the injection of saline.

5 . The device according to claim 1 , wherein the operation of step b comprises: constructing a lung ventilation image through changes in lung resistance of at least 5 consecutive breathing cycles within 1 minute before injection. 6 .

6 . The device according to claim 1 , wherein the operation of step c comprises: constructing a lung ventilation/blood flow distribution image with a threshold value of 20% of the maximum pixel point of the lung ventilation image and the pulmonary blood perfusion image. 7 .

7 . The device according to claim 1 , wherein the device comprises a data receiver, and the data receiver is responsible for receiving lung ventilation impedance data and lung blood perfusion impedance data determined based on a lung electrical impedance monitoring instrument; 7 . The data receiver is connected with the image processor.

8 . The device according to claim 7 , wherein the device further comprises a controller, and the controller is responsible for controlling and displaying at least one of a lung ventilation image and a lung blood perfusion image according to the screen mode and the measurement site. 9 .

9. The apparatus according to claim 8, wherein the controller comprises an image and waveform output control module, an impedance measurement control module, and an information determination and transmission module;

The image and waveform output control module can be configured to control and display at least one of a lung ventilation image, a lung blood flow perfusion impedance image, and a lung ventilation/blood flow distribution image according to a preset screen mode or a measurement site of an object to be monitored;

The impedance measurement control module can be configured to control the electrical impedance monitoring instrument to measure lung ventilation impedance data and pulmonary blood flow perfusion impedance data at the chest of the subject;

The information determination and transmission module may be configured to control the features implemented by the data receiver and the image processor, and to transmit the received lung ventilation impedance data, pulmonary blood flow perfusion impedance data, to the image processor such that the lung ventilation impedance The data, pulmonary perfusion impedance data, can be generated as an image.

10. An image monitoring system, characterized in that, the system comprises the image monitoring device according to any one of claims 1-9.

11. The system of claim 10, further comprising a lung electrical impedance monitoring instrument.

12. A system for diagnosing pulmonary embolism, characterized in that the system comprises a diagnosing device, the diagnosing device running the following method: the method comprising constructing a lung ventilation/blood flow distribution image using the method of claim 1, Calculate the dead space ventilation %, when the dead space ventilation %> 30.37%, the diagnosis of pulmonary embolism.

13. The system according to claim 12, characterized in that, the system further comprises the image monitoring device according to any one of claims 1-9.

14. The system of claim 13, further comprising a lung electrical impedance monitoring instrument.