Equal-dose Opposite Vessel Monitoring Pulmonary Artery-Pulmonary Vein CT Angiography Method and System

Abstract

The present invention relates to an equal-dose opposed-vessel monitoring pulmonary artery-pulmonary vein CT angiography method and system. For the method, the dose of the contrast agent bolus test, the flow rate and volume of the contrast agent, and the flow rate and volume of the normal saline are all consistent with those in the formal scan; during the bolus test, it is confirmed that a small amount of contrast agent flows into the pulmonary vein of the monitored slice while the pulmonary artery is filled, so as to obtain the optimal delay time of pulmonary artery CTA; it is confirmed that almost all of the contrast agent in the monitored slice has flowed through the pulmonary artery, and there is a trace amount of contrast agent at the end of the pulmonary artery near the periphery, so as to obtain the optimal delay time of pulmonary vein CTV. The system includes each module for realizing the above functions. The present invention can achieve accurate timing of pulmonary artery CTA and pulmonary vein left atrial CTV scans, and can also achieve accurate timing of combined one-stop right atrium ventricle pulmonary artery and pulmonary vein left atrium ventricle combined scans, realizing precise diagnosis and treatment.

Description

Technical Field

[0001] The present invention relates to the field of medical diagnosis, and more particularly, to a method and system for monitoring pulmonary artery-pulmonary vein CT angiography with equal-dose opposite blood vessels. Background Art

[0002] With the development of CT scanning technology, CT machines with more than 64 rows have been gradually popularized in China, promoting the booming development of CT angiography technology. Nowadays, CT angiography technology has been able to be applied to the examination of major arterial and venous vascular systems of the human body, providing important basis and reference for clinical diagnosis and treatment. Pulmonary artery CTA and pulmonary vein left atrial CTV play an irreplaceable guiding role in the diagnosis and treatment of major diseases such as pulmonary embolism, preoperative evaluation of atrial fibrillation, atrial flutter, premature ventricular contraction ablation surgery, and left atrial appendage occlusion surgery under interventional guidance, and the preparation of surgical plans. At present, the specific operation methods of pulmonary artery CTA and pulmonary vein left atrial CTV are as follows:

[0003] (1) Pulmonary artery CTA angiography examination technology: Using the threshold method, place the threshold monitoring point in the superior vena cava or the root of the pulmonary artery. While injecting the contrast agent, turn on the CT threshold automatic trigger exposure program. When the CT value of the monitoring point reaches the set threshold, the CT automatically triggers scanning to perform pulmonary artery CTA scanning.

[0004] (2) Small-dose monitoring method for pulmonary artery CTA angiography technology: Use the contrast agent and normal saline for the bolus test for pre-testing. After obtaining the time when the contrast agent reaches the root of the pulmonary artery through the time-density curve generated by the bolus test, judge the delay time empirically according to the arrival time, determine the delay time of pulmonary artery CTA, and then inject the contrast agent with the same flow rate as that in the small-dose program and the same amount of normal saline as that in the small-dose test at the same flow rate to perform pulmonary artery CTA scanning.

[0005] (3) Pulmonary vein left atrial CTV angiography technology: Using the threshold method, place the threshold monitoring point in the left atrial area near the opening of the pulmonary vein. When the CT value reaches the trigger threshold, the CT automatically triggers exposure scanning to perform pulmonary vein left atrial CTV scanning.

[0006] (4) Coronary artery mode modified pulmonary vein left atrial CTV angiography technology: Adopt the retrospective electrocardiogram gating coronary angiography program, connect the electrocardiogram gating lead to monitor the electrocardiogram of the subject, use the threshold method, place the threshold monitoring point in the left atrial area near the opening of the pulmonary vein, inject a contrast agent dose slightly less than that of coronary angiography and normal saline, and trigger the threshold to perform pulmonary vein left atrial CTV scanning.

[0007] (5) Directly use the retrospective electrocardiogram-gated coronary CTA scanning method for pulmonary vein left atrial CTV scanning: Utilize the same contrast agent protocol and CT scanning mode as the retrospective electrocardiogram-gated coronary CTA scanning, expand the scanning range to cover the entire pulmonary vein region, and perform pulmonary vein left atrial CTV scanning. Then use the CT post-processing workstation and the ordinary three-dimensional post-processing function (non-coronary post-processing program) to produce various reconstructed images of the pulmonary vein left atrial CTV.

[0008] However, there are the following physiological factors in the human body: 1. The differences in blood vessel distribution and hemodynamic performance in the human body; 2. The interlaced distribution of the pulmonary artery and pulmonary vein in human anatomy; 3. Both the pulmonary artery and pulmonary vein are connected to the heart, and the blood vessel position is directly affected by the heartbeat and will undergo large periodic displacements with the heartbeat; 4. The blood flow velocity is affected by the periodic opening and closing of the heart valves, and the blood flow velocity is not constant; 5. The characteristic of extremely fast blood flow velocity in the pulmonary blood vessels; 6. The influence of disease factors such as pulmonary hypertension that can cause changes in normal blood flow velocity; 7. The CT image motion artifacts caused by human breathing. These human physiological factors will cause varying degrees of deficiencies and defects in the methods of the five angiography techniques for synchronous monitoring of the pulmonary artery, pulmonary vein, and left atrium. Eventually, it will lead to deviations in the scanning results. The said deviations can be classified into two categories: 1. The scanning trigger time is too early or too late, ultimately resulting in filling defects of the contrast agent in the pulmonary artery, pulmonary vein, and left atrium, or simultaneous visualization of the pulmonary artery and pulmonary vein, leading to mutual interference and contamination on the tomographic images, and ultimately affecting the diagnosis of the images and making it impossible to determine whether there is pulmonary artery embolism. (There is pulmonary vein contamination in pulmonary artery CTA, and there is pulmonary artery contamination in pulmonary vein left atrial CTV). 2. The mutual contamination between the pulmonary artery and pulmonary vein makes it difficult for image post-processing: When there is mutual contamination between the pulmonary artery and pulmonary vein, due to the influence of physiological factor 2, the three-dimensional effect diagram will show a dense interlacing of the pulmonary artery and pulmonary vein, making it visually difficult to identify, and it is difficult to solve the problems of vascular interference and contamination between them through post-processing. Specifically, the problems existing in each of the five synchronous monitoring scanning techniques are as follows:

[0009] (1) Using the threshold method for pulmonary artery CTA angiography, due to the single and mechanical nature of its examination trigger method and the influence of the 7 physiological factors, it often leads to the above two types of deviation problems in the results.

[0010] (2) Although the small-dose monitoring program can provide the time-density curve information of the contrast agent reaching the pulmonary artery monitoring point and know the flow-through time of the contrast agent, due to the change in the contrast agent dose during the formal scanning and the influence of the 7 physiological factors, it cannot well solve deviation 1, and thus will cause the appearance of deviation 1 and 2 in the results.

[0011] (3) The reason is the same as that of the related technology (1).

[0012] (4) During retrospective electrocardiogram-gated coronary CTA examination, due to the CT performing depth overlapping scans with a small pitch, even if the rotation speed is increased, the problem of long scan time cannot be solved. Even when using a contrast agent dose lower than that of normal coronary CTA scans, since the triggering position is in the left atrium and the scan time is long, the contamination problem between the pulmonary artery and vein is reduced, but due to physiological factor 5, the problem of contrast agent filling defect in the pulmonary vein often occurs.

[0013] (5) The reason is the same as that in related art (4) and there is an over-reliance on statistical data. During coronary CTA scans, usually the contrast agent has basically flowed into the pulmonary vein and there is only a small amount or no contrast agent in the pulmonary artery. Therefore, physiological factor 1 can easily lead to two types of deviations in the results.

[0014] In addition, for the co-directional monitoring technology, that is, the scanned blood vessel is the monitoring point, and the triggering scan timing is mostly triggered by the flow of the contrast agent, it cannot well solve the deviation problems caused by individual differences, diseases, and hemodynamic changes, and it has its own limitations.

[0015] Generally speaking, due to the limitations of existing CT angiography technology and the influence of human physiological factors, there are always problems of contrast agent filling defect, mutual contamination and visual interference in the images between pulmonary artery CTA and left atrial CTV of pulmonary vein. At the same time, at present, there is no effective CT examination technology and method for clinicians to diagnose and screen the causes of pulmonary hypertension. The examination method of left atrial CTV of pulmonary vein also affects the accuracy of preoperative evaluation due to physiological factors and technical defects. Summary of the Invention

[0016] The purpose of the present invention is to provide an isodose co-directional vascular monitoring pulmonary artery-pulmonary vein CT angiography method and system with accurate scan timing control, optimized image quality, simplified post-processing, simple operation, low requirement for experience, and having clinical research value for helping clinicians diagnose patients with pulmonary hypertension and analyze its causes in view of the deficiencies in the prior art.

[0017] In a first aspect, the present invention provides an isodose opposed monitoring method for pulmonary artery and / or pulmonary vein CT angiography, including the steps of contrast agent bolus injection test and formal examination; the dose of the contrast agent bolus injection test is exactly the same as the dose regimen for injecting during the formal scanning of pulmonary artery CTA and / or pulmonary vein CTV, and the flow rate and flow volume of the contrast agent and the flow rate and flow volume of normal saline are kept consistent; the method for determining the optimal timing for scanning pulmonary artery CTA is as follows: during the bolus injection test, it is confirmed that there is a small amount of contrast agent flowing into the pulmonary vein at the monitoring level, but the concentration of the contrast agent is still below the threshold range for recognition and display by VRT reconstruction at the CT post-processing workstation, while the pulmonary artery shows filling. Through analysis of the time-density curve graph, the optimal delay time for pulmonary artery CTA is obtained, that is, the optimal timing for scanning pulmonary artery CTA; the method for determining the optimal timing for scanning pulmonary vein left atrial CTV is as follows: during the bolus injection test, it is confirmed that almost all of the contrast agent in the pulmonary artery at the monitoring level has flowed through, but there is still a small amount of contrast agent in the pulmonary artery near the distal end at the monitoring level, and the concentration has been reduced to below the threshold range for recognition and display by VRT reconstruction at the CT post-processing workstation, while the pulmonary vein shows filling. By monitoring the time-density curve in the pulmonary artery, the optimal delay time for pulmonary vein left atrial CTV is obtained, that is, the optimal timing for scanning pulmonary vein left atrial CTV.

[0018] Preferably, when performing combined scanning of the right atrium / ventricle / pulmonary artery and the pulmonary vein / left atrium / ventricle, the time-density curve information of the two scans is uploaded to the radiology reporting system for clinicians to diagnose the severity of pulmonary hypertension.

[0019] Preferably, clinicians further analyze the cause of pulmonary hypertension in combination with the patient's medical history.

[0020] Preferably, when performing combined scanning of the right atrium / ventricle / pulmonary artery and the pulmonary vein / left atrium / ventricle, the bed is advanced during the right atrium / ventricle / pulmonary artery phase and the bed is withdrawn during the pulmonary vein / left atrium / ventricle phase.

[0021] Preferably, when performing combined scanning of the right atrium / ventricle / pulmonary artery and the pulmonary vein / left atrium / ventricle, the scanning parameters are adjusted to the fastest scanning speed allowed for CTA scanning.

[0022] Preferably, when performing combined scanning of the right atrium / ventricle / pulmonary artery and the pulmonary vein / left atrium / ventricle, the amount of contrast agent is adjusted so that the time difference between the two-phase scans exceeds the shortest two-phase scan interval time of the device.

[0023] Preferably, the amount of contrast agent used in both the contrast agent bolus injection test and the formal examination for the combined scanning of the right atrium / ventricle / pulmonary artery and the pulmonary vein / left atrium / ventricle is 35 ml.

[0024] Preferably, when performing separate isodose opposed monitoring of pulmonary artery CTA or pulmonary vein left atrial CTV, the amount of contrast agent used in both the contrast agent bolus injection test and the formal examination is 25 ml.

[0025] In a second aspect, the present invention provides an equal-dose opposed monitoring pulmonary artery and / or pulmonary vein CT angiography system, comprising an X-ray tomography device and a computer system. The computer system includes a CT operation console, and the CT operation console includes a dynamic scanning module, a peripheral device transmission module, and an image processing module. The dynamic scanning module is used to execute a scanning command. The peripheral device transmission module is used to receive data from the X-ray tomography device and transmit it to the image processing module, and is also used to transmit images to a radiology reporting system. The image processing module is used to process data from the X-ray tomography device to generate a time-density curve graph. The CT operation console further includes a scanning timing acquisition module, and the scanning timing acquisition module includes an image recognition unit, a density recognition unit, a time recognition unit, and a scanning timing calculation unit. During a bolus injection test, the image recognition unit is used to recognize the scanning images of the monitored plane and identify the pulmonary veins and pulmonary arteries. The density recognition unit is used to recognize the densities of the pulmonary vein and pulmonary artery images. The time recognition unit is used to collect the specific scanning times at each density. The scanning timing calculation unit comprehensively considers the densities of the pulmonary veins and pulmonary arteries in the scanning images at each time point, identifies the time point when there is a small amount of contrast agent flowing into the pulmonary veins and the VRT reconstruction cannot yet recognize and display it, and the pulmonary artery is filled, thereby obtaining the optimal timing for scanning pulmonary artery CTA, and identifies the time point when almost all of the contrast agent has flowed through the pulmonary artery, there is a small amount of contrast agent at the end of the pulmonary artery near the periphery and the VRT reconstruction can no longer recognize and display it, and the left atrium of the pulmonary vein is filled, thereby obtaining the optimal timing for scanning pulmonary vein CTV.

[0026] Preferably, the scanning timing acquisition module transmits the obtained optimal scanning timing to the dynamic scanning module, and the dynamic scanning module automatically starts the formal scanning period according to the optimal scanning timing.

[0027] The equal-dose opposed vessel monitoring pulmonary artery-pulmonary vein left atrium CT angiography method and system of the present invention have the following advantages:

[0028] 1. It is easy to operate, has low requirements for experience, accurately controls the scanning timing, can perform pulmonary artery CTA and pulmonary vein left atrium CTV scans with accurate timing control separately as needed, and can also perform a one-stop pulmonary artery CTA and pulmonary vein left atrium CTV combined scan with accurate timing control. Since CTs with 64 rows or more have been widely popularized in China, and this technology can be applied without adding software and hardware, the promotion channels are already complete, which can accelerate the progress of pulmonary vascular and cardiovascular examination and diagnosis technologies in China, promote the development of diagnosis and treatment technologies for pulmonary vascular diseases and cardiovascular diseases, and better benefit the general public.

[0029] 2. Overcome the interference of human physiological factors on pulmonary artery CTA and left atrial CTV of pulmonary veins, ensure the filling of contrast agent in the vessels to be examined, and minimize the mutual contamination between the pulmonary artery and the pulmonary veins.

[0030] 3. Simplify the three-dimensional post-processing steps to the greatest extent and optimize the efficiency: When reconstructing three-dimensional images such as VRT and MIP, since there are almost no interfering vessels, almost no cutting or removal of interfering vessels is required during the cutting process. The steps are simplified. Just appropriately adjust the window width, window level, brightness, and contrast of the three-dimensional VRT and MIP images to complete the three-dimensional vascular images of the examination. The efficiency of three-dimensional post-processing has been greatly improved.

[0031] 4. Optimize the image quality: Basically solve the problem of mutual contamination between the pulmonary artery and the pulmonary veins. On the tomographic images, the blood vessels of the pulmonary artery system and the pulmonary vein system are clearly distinguishable, which is convenient for identification and greatly improves the accuracy of diagnosis.

[0032] 5. The left atrial CTV of the pulmonary veins can be used for radiofrequency / cryoablation of atrial flutter, atrial fibrillation, ventricular premature beats, etc., and the evaluation before and after left atrial appendage occlusion. The method of the present invention can ensure the filling display of contrast agent at the pulmonary veins, left atrium, and left atrial appendage. Each branch of the pulmonary veins is clearly shown without visual interference from the pulmonary artery.

[0033] 6. By realizing one-stop scanning, the staging scans of the right atrium, right ventricle, and pulmonary artery phase, and the left atrium, ventricle, and pulmonary vein phase. After three-dimensional post-processing, combined with the accurate time node data of the two-phase scans, a CT imaging examination method for the cardio-pulmonary vessels of pulmonary hypertension is provided to help clinicians diagnose the pulmonary hypertension of patients and analyze its causes in combination with the medical history.

[0034] 7. By realizing one-stop scanning, it is also possible to be promoted and applied clinically as a non-invasive examination method that can simultaneously detect pulmonary embolism and screen for pulmonary hypertension.

[0035] 8. If the present invention cooperates with existing CT manufacturers and improves in combination with the mechanical and software technologies of existing CT manufacturers, CT scan examinations with lower contrast agent dosage, lower radiation dose, and safer for the examinees can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 : The time-density curve of the bolus injection test of pulmonary artery CTA, and the delay time of pulmonary artery CTA is determined by monitoring the pulmonary veins (marked by arrows).

[0037] Figure 2 : The tomographic image of pulmonary artery CTA, showing that the pulmonary artery and the pulmonary veins can be clearly distinguished on the tomographic image.

[0038] Figure 3: Post - processing VRT three - dimensional effect diagram of pulmonary artery CTA, showing no contamination of the opposite pulmonary vein.

[0039] Figure 4 : Time - density curve of the left atrium - pulmonary vein CTV of the pulmonary vein, and the time display is the delay time determined by monitoring the pulmonary artery (marked by the arrow).

[0040] Figure 5 : Tomographic image of the left atrium - pulmonary vein CTV of the pulmonary vein, showing obvious distinction between the pulmonary vein and the pulmonary artery endings.

[0041] Figure 6 : VRT effect diagram of the pulmonary vein of the left atrium - pulmonary vein CTV, showing no pulmonary artery contamination, and the displayed structure and contour of the left atrial appendage are clear.

[0042] Figure 7 : Time - density curve of the right atrium - ventricle - pulmonary artery phase of the one - stop scan, showing the time as the specific delay time of the scan.

[0043] Figure 8 : Time - density curve of the left atrium - ventricle - pulmonary vein phase of the one - stop scan, showing the time as the specific delay time of the scan.

[0044] Figure 9 : Effect diagram of the right atrium - ventricle - pulmonary artery phase of the one - stop scan.

[0045] Figure 10 : Effect diagram of the left atrium - ventricle - pulmonary vein phase of the one - stop scan. Clearly visible pulmonary veins, left atrium, left atrial appendage, and left ventricle can be seen.

[0046] Figure 11 : Time - density curves and scan delay times of the right atrium - ventricle - artery phase and the left atrium - ventricle - vein phase of the one - stop examination for patients with pulmonary hypertension. Through monitoring, it can be seen that the blood flow velocity of patients with pulmonary hypertension is much slower than that of normal people, suggesting that the subject is likely to have pulmonary hypertension.

[0047] Figure 12 : VRT post - processing diagram of the right atrium - ventricle - pulmonary artery phase of the one - stop examination for patients with pulmonary hypertension, showing that during the formal scan of the right atrium - ventricle - pulmonary artery phase, the pulmonary artery is filled with contrast agent, the contrast agent in the front segment diffuses in the pulmonary vein, forming pulmonary vein contamination (indicating that the slow blood flow velocity leads to the diffusion of the contrast agent in the blood vessel), and the cavity of the right atrium and ventricle increases, which is in line with the imaging manifestations of pulmonary hypertension.

[0048] Figure 13 : VRT post - processing effect diagram of the left atrium - ventricle - pulmonary vein phase of the one - stop examination for patients with pulmonary hypertension, showing an enlarged left atrium, and the patient has had a single - chamber pacemaker implanted.

[0049] Figure 14: The one-stop pulmonary vascular and cardiac left and right atria and ventricles scanning method provides a practical spatial positioning technique for the spatial positioning of the cardiac pacemaker electrode wire in the human body and the implantation position of the wire head on the cardiac chamber wall. By using VRT and inverse MIP reconstructions on the CT post-processing workstation, the positional relationship between the pacemaker electrode wire and the heart can be accurately reflected, achieving a non-invasive CT examination method more accurate than DSA. (Two-phase images show the pacemaker electrode wire at the position of the interventricular septum between the left and right ventricles.)

[0050] Figure 15 : Block diagram of the structure of the equal-dose opposite-direction monitoring pulmonary artery and / or pulmonary vein CT angiography system of the present invention. Detailed implementation mode

[0051] The equal-dose opposite-direction vascular monitoring pulmonary artery-pulmonary vein CT angiography method of the present invention is a CT angiography scanning technique based on the combination of the CT bolus injection test technique (Test-Bolus) and the equal-dose opposite-direction vascular monitoring technique discovered by the present inventor. It can achieve accurate imaging of the pulmonary artery and pulmonary vein scanning images, basically solving the problems of interference and contamination between the contrast agent filling defect and the pulmonary artery and vein vascular images during pulmonary artery and pulmonary vein CT angiography, achieving the purpose of accurate scanning phase, accurately distinguishing the pulmonary artery and vein systems on the images, and greatly improving the clinical diagnosis accuracy. Through this technique, accurate pulmonary artery CTA and pulmonary vein left atrial CTV with accurate scanning timing can be achieved. It can also achieve combined one-stop scanning of the right atrium, ventricle, pulmonary artery, pulmonary vein, left atrium, and ventricle with accurate scanning timing.

[0052] The equal-dose opposite-direction monitoring pulmonary artery-pulmonary vein CT angiography method and system of the present invention will be introduced in detail below with reference to the accompanying drawings.

[0053] The reference numerals and components involved in the accompanying drawings are as follows:

[0054] 1. X-ray tomographic scanning device 2. Computer system 3. CT operation console 31. Dynamic scanning module 32. Peripheral transfer module 33. Image processing module 34. Scanning timing acquisition module 341. Image recognition unit 342. Density recognition unit 343. Time recognition unit 344. Scanning timing calculation unit 4. Radiology reporting system

[0055] Example 1 The equal-dose opposite-direction monitoring pulmonary artery-pulmonary vein CT angiography method of the present invention

[0056] Principle of the equal-dose opposite-direction vascular monitoring technique

[0057] 1. Equal-dose monitoring technique

[0058] The dose of the contrast agent bolus injection test is exactly the same as the dose scheme for injecting during the formal scanning of pulmonary artery CTA or pulmonary vein CTA. The flow rate and flow volume of the contrast agent and the flow rate and flow volume of the normal saline are kept the same. This can maximize the consistency of the monitoring data and the dynamic distribution of the contrast agent during the formal scanning, and there will be no problem of errors caused by the need to calculate with the small-dose method, which is suitable for pulmonary vascular angiography with many influencing factors.

[0059] 2. Opposite Vessel Monitoring Technology:

[0060] There is a capillary and microvascular system between the arterial and venous systems. This vascular system will impede blood flow and reduce blood flow velocity due to the gradual narrowing of the blood vessels. There are capillary and microvascular systems and alveolar sacs between the pulmonary artery and the pulmonary vein. For this reason, the blood flow speed slows down during the journey from the pulmonary artery terminal to the pulmonary vein terminal, providing a time window of about 2 seconds for the scanning of the pulmonary artery and the pulmonary vein. The opposite vessel monitoring technology was invented based on this phenomenon.

[0061] When the contrast agent is injected into the human blood vessels, due to the pumping action of the heart, the contrast agent will be pumped out by the right atrium and ventricle and quickly fill the pulmonary artery. When the pulmonary artery branches are completely filled at the terminal, it will be blocked by the terminal capillary and microvascular systems and alveolar sacs, and then quickly sucked into the left atrium due to the pumping action of the heart after entering the pulmonary vein terminal. Therefore, based on the above analysis:

[0062] The best triggering time for pulmonary artery CTA scanning is when a small amount of contrast agent enters the pulmonary vein near the terminal, because at this time the contrast agent must have filled the entire pulmonary artery system, and the concentration of the contrast agent in the pulmonary vein has not yet reached the threshold that can be recognized by the 3D reconstruction function of the CT workstation. Therefore, during the bolus test, it is only necessary to confirm that there is a small amount of contrast agent flowing into the pulmonary vein at the monitoring level, which cannot be recognized and displayed by VRT post-processing, while the pulmonary artery is filled. By analyzing the time-density curve, the best delay time for pulmonary artery CTA can be confirmed.

[0063] The triggering time for CTV scanning of the left atrium of the pulmonary vein is also based on the time window provided by the blockage of the terminal capillary and microvascular systems and alveolar sacs. The difference is that after the contrast agent flows through the pulmonary artery, a sufficient amount of contrast agent is required to fill the pulmonary vein branches and the left atrium and ventricle. According to past experience, 25 ml of contrast agent can ensure the filling of the pulmonary vein branches, the left atrium and ventricle, and the aorta in the chest cavity of the subject. Therefore, it is only necessary to confirm that almost all of the 25 ml of contrast agent has flowed through the pulmonary artery and there is a small amount of contrast agent in the terminal segment of the pulmonary artery near the end, and the timing when the CT workstation VRT reconstruction function can no longer recognize these small amounts of contrast agent is the best timing for scanning the CTV of the pulmonary vein. At the bolus test level, the best delay time for the CTV of the pulmonary vein can be confirmed by monitoring the time-density curve near the terminal segment of the pulmonary artery.

[0064] The specific steps of the equal-dose opposite monitoring pulmonary artery-pulmonary vein CT angiography method are as follows:

[0065] I. Preparation before examination:

[0066] 1. The subject should fast for 4 hours before the examination; (For emergency patients, depending on the specific situation, they can be directly examined if necessary.)

[0067] 2. Establish a venous access in the cubital vein and conduct a pre-test for contrast agent allergy;

[0068] 3. The patient lies flat in the foot-first direction and is supine on the CT examination table. Before the CTA examination of the subject, inform the patient about the preparations and the reactions of the contrast agent in the human body; instruct the patient to breathe calmly when injecting the contrast agent;

[0069] 4. Connect the CT high-pressure syringe and conduct a patency test with normal saline;

[0070] 5. Positioning preparation: Align the horizontal positioning line with the midaxillary line of the patient and the vertical positioning line with the patient's neck;

[0071] 6. After informing the patient that the examination is about to start, leave the computer room and prepare to start the operation on the machine.

[0072] II. Contrast agent protocol:

[0073] 1. When performing an isodose opposite monitoring pulmonary artery CTA or pulmonary vein left atrium CTV examination alone:

[0074] 350 mgI / ml contrast agent, total volume 50 ml, 0.9% normal saline 60 ml in total.

[0075] (1) During the bolus injection test: Flow rate 4.5 ml / s, 25 ml contrast agent, 30 ml normal saline; Inject the contrast agent and normal saline in sequence;

[0076] (2) During the formal examination: Flow rate 4.5 ml / s, 25 ml contrast agent, 30 ml normal saline; Inject the contrast agent and normal saline in sequence;

[0077] 2. When performing a combined examination of isodose opposite monitoring pulmonary artery CTA and pulmonary vein left atrium CTV:

[0078] 350 mgI / ml contrast agent, total volume 70 ml, 0.9% normal saline 60 ml in total.

[0079] (1) During the bolus injection test: Flow rate 4.5 ml / s, 35 ml contrast agent, 30 ml normal saline, inject the contrast agent and normal saline in sequence;

[0080] (2) During the formal examination: Flow rate 4.5 ml / s, 35 ml contrast agent, 30 ml normal saline, inject the contrast agent and normal saline in sequence;

[0081] III. Start the examination. The examination scanning process is as follows:

[0082] (I) When performing an isodose opposite monitoring pulmonary artery CTA or pulmonary vein left atrium CTV examination alone:

[0083] 1. Perform a positioning scan to cover the entire lungs of the subject;

[0084] 2. Instruct the patient to hold their breath directly, and perform a helical overlapping plain scan of the chest CT with a slice thickness of 10 mm and an interval of 5 mm in the mediastinal window for the entire lungs of the examinee; (see Note 1 for reasons)

[0085] 3. Select appropriate monitoring slices (see Note 2), perform an equal-dose bolus injection test, and start injecting with the high-pressure syringe simultaneously while starting the Test Bolus program. Contrast agent protocol: 4.5 ml / s, 25 ml of contrast agent, and 30 ml of normal saline.

[0086] (3.1) When performing pulmonary artery CTA alone: Observe until the contrast agent flows into the pulmonary vein and the blood vessels turn white and bright on the monitoring slice, then stop the Test Bolus program of the bolus injection test.

[0087] (3.2) When performing CTV of the left atrium of the pulmonary vein alone: Observe until the contrast agent completely flows through the pulmonary artery (when there is no contrast agent in the pulmonary artery and it becomes completely dark), then stop the Test Bolus program of the bolus injection test.

[0088] 4. Use the time-density curve analysis program on the CT machine to load the image sequence of the bolus injection test, and observe the change in CT value in the monitored blood vessel in the opposite direction to determine the exact delay time for the formal scan of the blood vessel to be examined. (see Note 3 for reasons)

[0089] (4.1) Method for determining the exact delay time of pulmonary artery CTA: The exact time when the CT value in the monitored pulmonary vein branch blood vessel reaches 80 HU (±5 HU) is directly used as the delay time for the formal scan of pulmonary artery CTA.

[0090] (4.2) Method for determining the exact delay time of CTV of the left atrium of the pulmonary vein: The exact time when the CT value in the monitored pulmonary artery branch blood vessel drops to 90 HU (±5 HU) is directly used as the delay time for the formal scan of CTV of the left atrium of the pulmonary vein.

[0091] 5. Input the previously confirmed delay time as the delay time for the formal scans of pulmonary artery CTA and CTV of the pulmonary vein into the CT mainframe. While the patient is breathing quietly, execute the exposure program, and inject the contrast agent while pressing the exposure button to start the scan. The dose protocol is the same as in examination process 3. The scope of the formal scan should be minimized as much as possible to cover the range of the blood vessels to be examined. A scan time as short as possible can reduce the radiation dose, and at the same time, it can also try to keep the scanning timing within the time window or as close to the time window as possible. (see Note 3-1)

[0092] 6. After scanning, observe the quality of the scanned and reconstructed images. After confirming that the blood vessels to be examined are filled and the contamination of the blood vessels on the contralateral side is within an appropriate range, end the examination.

[0093] 7. Reconstruct three-dimensional effect diagrams using thin-layer images from formal scans on a CT workstation.

[0094] Remove redundant major blood vessels: For pulmonary artery CTA, the superior vena cava, right atrium, and right ventricle need to be removed; for pulmonary vein left atrium CTV, a local part of the left ventricle and the aorta need to be removed. After slightly adjusting the window width and window level and performing a small amount of cutting operations to remove the contrast agent contamination of the contralateral blood vessels, adjust the image to an appropriate size, save three-dimensional post-processing images such as VRT, MIP, and MPR, and upload them to PACS (Radiology Reporting System).

[0095] (2) When performing combined scans of the right atrium / ventricle / pulmonary artery and the left atrium / ventricle / pulmonary vein:

[0096] Steps 1, 2, 4, 6, and 7 are the same as above.

[0097] 3. Select appropriate monitoring levels (see Note 2), perform an equal-dose bolus injection test, and start injecting with the high-pressure syringe simultaneously when starting the Test Bolus program. Contrast agent protocol: Inject 4.5 ml / s, 35 ml of contrast agent, and 30 ml of normal saline in sequence. At the monitoring level, observe the contrast agent starting to flow into the pulmonary artery until the pulmonary artery completely darkens, and stop the Test Bolus program when it flows through the ascending aorta.

[0098] 5. The formal scan period for combined scans of the right atrium / ventricle / pulmonary artery and the left atrium / ventricle / pulmonary vein is two delayed scans in the case of a single bolus injection of contrast agent. The time interval between the two scans increases with the increase in the contrast agent dose. To minimize the contrast agent dosage as much as possible and control the delay time within a reasonable range, the following measures must be taken:

[0099] (1) Use bed-in scanning for the right atrium / ventricle / pulmonary artery phase and bed-out scanning for the left atrium / ventricle / pulmonary vein phase.

[0100] (2) Adjust the scanning parameters to the fastest scanning speed:

[0101] Adjust the upper collimator width of the CT machine to the widest, and adjust the pitch and rotation speed to the fastest scanning scheme allowed for CTA examinations. When the upper collimator width of our hospital's 128-slice CT is 128 * 0.625 mm, the pitch is 0.925, and the rotation speed is 0.4 seconds / rotation, the scanning time for covering the entire pulmonary artery and vein can be controlled within 2 seconds for a single one-way scan. For CTs with 256 slices or more and dual-source CTs, due to their advantages in the number of slices and rotation speed, the scanning effect is better. For 64-slice CTs, due to the limitation of the number of slices and slightly lower rotation speed, the scanning time is slightly longer, and there may be a small amount of blood vessel contamination and interference between the pulmonary artery and vein.

[0102] (3) By adjusting the amount of contrast agent, the time delay difference between the two-phase scans is made to exceed the shortest interval time between the two-phase scans of the device. Currently, 35 ml of contrast agent can meet the requirements. In the case of patients with a larger build or when using a 64-slice CT for examination, the contrast agent dose can be appropriately increased. However, since an equal-dose bolus injection test is used to ensure the accuracy of the scanning timing, the contrast agent dose must be controlled to the lowest possible level to protect the safety of the examinee.

[0103] After taking the above three measures, the normal progress of the two scans of the right atrium, right ventricle, pulmonary artery phase and the pulmonary vein, left atrium, left ventricle can be ensured.

[0104] For the combined scan of the right atrium, right ventricle, pulmonary artery and the pulmonary vein, left atrium, left ventricle, finally, the time-density curve information of the two scans must be uploaded to the radiology reporting system (PACS) for clinicians to study the severity of pulmonary hypertension.

[0105] The above content is the complete description of the equal-dose opposite-vessel monitoring pulmonary artery-pulmonary vein CT angiography.

[0106] The relevant annotations are described as follows:

[0107] Annotation 1: There are three reasons:

[0108] (1) Influence of physiological factors on the bolus injection test:

[0109] When injecting the contrast agent in a bolus, it is necessary to observe the entire process of the contrast agent flowing through the area of the blood vessels being examined, which takes a slightly longer time (usually more than 10 seconds). If the patient is asked to inhale and hold their breath as in a normal chest plain scan, it is difficult for the patient to do so. Moreover, even if the patient inhales and holds their breath, since both the pulmonary artery and the pulmonary vein are connected to the heart and are the closest, their own pulsations are greatly affected by the heart pulsations and have a large pulsation amplitude, which is of little significance.

[0110] (2) Inhaling and holding the breath for a plain scan will cause misalignment between the selected slice and the slice for bolus injection test monitoring. Therefore, the patient should be asked to hold their breath directly during the chest plain scan.

[0111] (3) This examination technology is applied in our hospital on the Philips 128-row (256-layer) Brilliance iCT. The slice thickness of the bolus test program Test Bolus is set to 10 mm and cannot be changed. The purpose of the mediastinal window chest scan with a slice thickness of 10 mm and a slice spacing of 5 mm is to select the appropriate layer for the next bolus test through the transverse image. To ensure the accuracy of the layer selection and to eliminate the inaccurate layer selection of the Test Bolus program caused by the difference in layer thickness, which affects the accuracy of the bolus test results, the same 10 mm slice thickness and 5 mm slice spacing as the Test Bolus program can be set to find the appropriate layer in detail, overcome the vascular shaking caused by human physiological factors, and ensure the reasonable and accurate selection of the bolus test layer.

[0112] Note 2: Methods for confirming the appropriate level:

[0113] In the chest plain scan mediastinal window image with 10mm slice thickness and 5mm slice spacing, search for the layers where both the pulmonary artery and pulmonary vein branches are displayed. The diameter of the pulmonary artery and pulmonary vein branches at the layer used for monitoring should preferably be larger than 1 / 4 of the root of the pulmonary artery. Try to select layers with less influence of vascular pulsation to prevent distortion of the time density curve caused by vascular pulsation. Because the trachea and vascular trunks are intertwined within the hilar range and have more constraints on each other, the influence of vascular pulsation is much less than that of other lung layers, and it meets the diameter requirements of the above two blood vessels. Therefore, it is better to choose the layer within the hilar range.

[0114] Note 3: The exact delay time is determined based on:

[0115] 1. Anatomical principles:

[0116] When blood flows through the pulmonary blood vessels and the heart, it will flow through the superior vena cava, right atrium, right ventricle, pulmonary artery branches, pulmonary artery capillaries, alveoli, pulmonary vein capillaries, pulmonary vein branches, left atrium, left ventricle, and aorta in order. Because of the pumping action of the heart, the human body's venous blood and air are fully combined in the alveoli to become arterial blood, which is supplied to all parts of the human body by the aorta. The blood flow rate in the lungs has always been very fast, which is also the main reason why the relevant pulmonary vascular scanning time nodes were difficult to control in the past. However, the blood flow rate in the pulmonary artery capillaries, alveoli, and pulmonary vein capillaries is reduced due to the narrow lumen and dense capillaries. The time for blood to flow through here is slightly more than 2 seconds, thereby providing a time window for the opposite monitoring angiography method. After repeated verification by the inventor:

[0117] (1) During pulmonary artery CTA examination, the entire pulmonary artery is scanned. When the contrast agent concentration in the pulmonary vein branches at the monitoring level of the bolus test reaches about 80 HU, the entire pulmonary artery is scanned, which can ensure that the pulmonary artery trunk is fully filled with contrast agent and a small amount of contrast agent enters the pulmonary vein endings. For the pulmonary artery images obtained from the formal scan, after three-dimensional post-processing on the Philips CT Nebula workstation, the pulmonary veins cannot be identified and are not visualized.

[0118] (2) During CTV examination of the left atrium of the pulmonary vein, when the contrast agent concentration in the pulmonary artery branches at the monitoring level of the bolus test drops to about 150 HU, the entire pulmonary vein is scanned, which can ensure that only a small amount of contrast agent remains in the pulmonary artery endings, and the vast majority of the contrast agent flows into the pulmonary vein, left atrium, left ventricle, and aorta to ensure filling. For the images of the left atrium of the pulmonary vein obtained from the formal scan, after CT three-dimensional post-processing on the Philips CT Nebula workstation, the pulmonary artery cannot be identified and is not visualized.

[0119] 2. Characteristics of contrast agent injection:

[0120] When iodinated contrast agent is injected, the contrast agent concentration in the blood vessels will increase with the increase of the injection speed and volume. After entering the blood vessels, the CT value at the monitoring point of the contrast agent bolus test layer will gradually rise. Then, due to the end of the contrast agent injection and the injection of normal saline, the concentration will gradually decrease to the CT value of the blood in normal blood vessels. Using this phenomenon, the time-density curve can provide accurate real-time dynamic analysis of the contrast agent, helping to determine the exact delay time.

[0121] 3. Basic principle of three-dimensional reconstruction of blood vessels on the three-dimensional post-processing workstation:

[0122] The principle of three-dimensional post-processing of the body blood vessels on the CT post-processing workstation is a screening program based on screening the pixel brightness values within the image range, and the pixel brightness corresponds to the CT value in CT examination. Iodinated contrast agent is a high-density liquid, which will be highlighted on CT and the CT value is also higher than that of normal tissues. When the blood vessel post-processing program runs, the computer will automatically screen out the substances with a density higher than the specified CT value within the image range, and then according to the human model in the software, remove the bone structures such as the ribs, vertebrae, and sternum in the chest, display the internal CT contrast agent distribution, and then realize the display of the three-dimensional effect diagram of the blood vessels. Usually, the CT value used for screening is set at about 150 HU to remove normal soft tissues.

[0123] For the above three reasons, during the examination, it is only necessary to ensure that a small amount of contrast agent remains in the opposite blood vessels between the pulmonary artery and the pulmonary vein. These residual contrast agents have a CT value lower than the threshold for VRT reconstruction recognition during the formal scan.

[0124] Example 2 The equal-dose opposite monitoring pulmonary artery-pulmonary vein CT angiography system of the present invention

[0125] Please refer toFigure 15 , Figure 15 is a structural block diagram of the isodose opposed monitoring pulmonary artery and / or pulmonary vein CT angiography system of the present invention. The isodose opposed monitoring pulmonary artery and / or pulmonary vein CT angiography system of the present invention includes an X-ray tomography device 1 and a computer system 2. The computer system includes a CT operation console 3. The CT operation console 3 includes a dynamic scanning module 31, a peripheral transmission module 32, and an image processing module 33. The dynamic scanning module 31 is used to execute a scanning command; the peripheral transmission module 32 is used to receive the data of the X-ray tomography device 1 and transmit it to the image processing module 33, and is also used to transmit the image to the radiology reporting system 4; the image processing module 33 is used to process the data of the X-ray tomography device 1 to generate a time-density curve graph; the CT operation console 3 further includes a scanning timing acquisition module 34. The scanning timing acquisition module 34 includes an image recognition unit 341, a density recognition unit 342, a time recognition unit 343, and a scanning timing calculation unit 344. During a bolus injection test, the image recognition unit 341 is used to recognize the scanning images of the monitoring layer, recognize the pulmonary vein and the pulmonary artery. The density recognition unit 342 is used to recognize the density of the pulmonary vein and pulmonary artery images. The time recognition unit 343 is used to collect the specific scanning time at each density. The scanning timing calculation unit 344 comprehensively analyzes the densities of the pulmonary vein and pulmonary artery in the scanning images at each time point, recognizes the time point when there is a small amount of contrast agent flowing into the pulmonary vein and the VRT reconstruction cannot yet recognize and display it, and the pulmonary artery is filled, and obtains the best timing for scanning the pulmonary artery CTA. And it recognizes the time point when the contrast agent has almost completely flowed through the pulmonary artery, there is a small amount of contrast agent at the end of the pulmonary artery near the terminal, and the VRT reconstruction can no longer recognize and display it, and the left atrium of the pulmonary vein is filled, and obtains the best timing for scanning the pulmonary vein CTV. Further, the scanning timing acquisition module 34 transmits the obtained best scanning timing to the dynamic scanning module 31, and the dynamic scanning module 31 automatically starts the formal scanning period according to the best scanning timing.

[0126] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the method of the present invention, several improvements and supplements can be made, and these improvements and supplements should also be regarded as the protection scope of the present invention.

Claims

1. An equal-dose opposite-direction monitoring pulmonary artery and / or pulmonary vein CT angiography method, characterized in that, It includes the steps of contrast agent bolus test and the steps of formal examination; the dose of the contrast agent bolus test is exactly the same as the dose regimen injected during the formal scanning of pulmonary artery CTA and / or pulmonary vein CTA, and the flow rate and flow volume of the contrast agent and the flow rate and flow volume of normal saline are kept consistent; the method for determining the optimal timing of scanning pulmonary artery CTA is: during the bolus test, it is confirmed that there is a small amount of contrast agent flowing into the pulmonary vein at the monitoring level, but the concentration of the contrast agent is still below the threshold range that can be identified and displayed by the VRT reconstruction in the CT post-processing workstation, while the pulmonary artery shows filling. Through the analysis of the time-density curve graph, the optimal delay time for pulmonary artery CTA is obtained, that is, the optimal timing of scanning pulmonary artery CTA; the method for determining the optimal timing of scanning pulmonary vein left atrial CTV is: during the bolus test, it is confirmed that almost all of the contrast agent in the pulmonary artery at the monitoring level has flowed through, but there is still a small amount of contrast agent in the pulmonary artery near the distal end at the monitoring level, and the concentration has been reduced to below the threshold range that can be identified and displayed by the VRT reconstruction in the CT post-processing workstation, while the pulmonary vein shows filling. By monitoring the time-density curve in the pulmonary artery, the optimal delay time for pulmonary vein left atrial CTV is obtained, that is, the optimal timing of scanning pulmonary vein left atrial CTV.

2. The equal-dose opposite-direction monitoring pulmonary artery and / or pulmonary vein CT angiography method according to claim 1, characterized in that, During the combined scan of right atrium ventricle pulmonary artery and pulmonary vein left atrium ventricle, the time-density curve information of the two scans is uploaded to the radiology reporting system for clinicians to diagnose the severity of pulmonary hypertension.

3. The isodose opposite monitoring pulmonary artery and / or pulmonary vein CT angiography method according to claim 1, characterized in that, During the combined scan of right atrium ventricle pulmonary artery and pulmonary vein left atrium ventricle, the table feed scan is used in the right atrium ventricle pulmonary artery phase, and the table out scan is used in the pulmonary vein left atrium ventricle phase.

4. The equal-dose opposite-direction monitoring pulmonary artery and / or pulmonary vein CT angiography method according to claim 1, characterized in that During the combined scan of right atrium ventricle pulmonary artery and pulmonary vein left atrium ventricle, the scanning parameters are adjusted to the fastest scanning speed allowed for CTA scanning.

5. The isodose opposite monitoring pulmonary artery and / or pulmonary vein CT angiography method according to claim 1, characterized in that, During the combined scan of right atrium ventricle pulmonary artery and pulmonary vein left atrium ventricle, the amount of contrast agent is adjusted so that the time delay difference between the two-phase scans exceeds the shortest two-phase scan interval time of the equipment.

6. The equal-dose opposite monitoring pulmonary artery and / or pulmonary vein CT angiography method according to claim 5, characterized in that, The contrast agent dosage for both the contrast agent bolus test and the formal examination in the combined scan of right atrium ventricle pulmonary artery and pulmonary vein left atrium ventricle is 35 ml.

7. The isodose opposite monitoring pulmonary artery and / or pulmonary vein CT angiography method according to claim 1, characterized in that, When performing an equal-dose opposite monitoring pulmonary artery CTA or pulmonary vein left atrial CTV examination alone, the contrast agent dosage for both the contrast agent bolus test and the formal examination is 25 ml.

8. An equal-dose opposite-direction monitoring pulmonary artery and / or pulmonary vein CT angiography system, characterized in that, It includes an X-ray tomography device and a computer system. The computer system includes a CT console, and the CT console includes a dynamic scanning module, a peripheral transmission module, and an image processing module. The dynamic scanning module is used to execute scanning commands. The peripheral transmission module is used to receive the data of the X-ray tomography device and transmit it to the image processing module, and is also used to transmit the image to the radiology reporting system. The image processing module is used to process the data of the X-ray tomography device and generate a time-density curve graph. The CT console further includes a scanning timing acquisition module. The scanning timing acquisition module includes an image recognition unit, a density recognition unit, a time recognition unit, and a scanning timing calculation unit. During a bolus injection test, the image recognition unit is used to recognize the scanning images of the monitoring layer and identify the pulmonary veins and pulmonary arteries. The density recognition unit is used to recognize the densities of the pulmonary vein and pulmonary artery images. The time recognition unit is used to collect the specific scanning times at various densities. The scanning timing calculation unit comprehensively analyzes the densities of the pulmonary veins and pulmonary arteries in the scanning images at each time point, identifies the time points when there is a small amount of contrast agent flowing into the pulmonary veins and the pulmonary artery shows filling while the VRT reconstruction function cannot yet identify and display, and obtains the optimal timing for scanning the pulmonary artery CTA. It also identifies the time points when almost all of the contrast agent has flowed through the pulmonary artery, there is a small amount of contrast agent at the end of the pulmonary artery near the periphery, and the VRT reconstruction function can no longer identify and display, and the left atrium of the pulmonary vein shows filling, and obtains the optimal timing for scanning the pulmonary vein CTV.

9. The equal-dose opposite-direction monitoring pulmonary artery and / or pulmonary vein CT angiography system according to claim 8, wherein The scanning timing acquisition module transmits the obtained optimal scanning timing to the dynamic scanning module, and the dynamic scanning module automatically starts the formal scanning period according to the optimal scanning timing.

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