Iodine contrast agent injection method for reducing pulmonary vein CT scanning times

Abstract

The invention provides an iodine contrast agent injection method for reducing pulmonary vein CT scanning times, the injection method adopts a three-stage contrast agent injection method, and the method comprises the following steps: 1, injecting a mixed solution of an iodine contrast agent and normal saline in the first stage; 2, injecting the iodine contrast agent at the second stage, and starting to inject after the injection of the mixed solution at the first stage is delayed for 40 seconds; and 3, injecting normal saline at the third stage. The left atrial ear blood circulation stasis or left atrial ear thrombus can be distinguished through one-time scanning, so that the scanning frequency is reduced, and the radiation dose of a patient is reduced.

Description

Technical Field

[0001] The invention belongs to the field of biomedical technology, and in particular relates to an iodine contrast agent injection method for reducing the number of pulmonary vein CT scans. Background Art

[0002] In CT scanning, when the density of diseased tissues and organs is close to that of normal tissues, the lesion site is not easy to display. After the iodine contrast agent is injected, the image contrast increases, the boundary between the diseased tissue and the normal tissue becomes clearer, and its density, shape, size, etc. are more prominent, which is conducive to the detection and diagnosis of lesions. The total amount, flow rate and injection time of iodine contrast agent injection are different for different organ enhanced CT scanning. When scanning blood vessels, a high flow rate is required to make the iodine contrast agent fill the target blood vessel instantly, so as to observe whether the target blood vessel has a filling defect, and to determine whether there is a vascular lesion. Atrial fibrillation is the most common arrhythmia, and patients are at risk of thromboembolism, which is associated with increased disability and mortality. Catheter ablation (CA) to isolate the pulmonary veins is a common method for treating atrial fibrillation. Before ablation, it is necessary to evaluate whether there is a thrombus in the left atrium (LA) or left atrial appendage (LAA). The operation may cause the thrombus to fall off and lead to thromboembolic complications. Therefore, a CT scan of the left atrium and pulmonary veins will be performed before radiofrequency ablation to observe the morphology of the left atrium and pulmonary veins and whether there is a filling defect in the left atrial appendage. If there is a filling defect in the left atrial appendage, it is necessary to distinguish whether it is blood stasis or a thrombus in the left atrial appendage. The result directly affects the radiofrequency ablation surgical plan.

[0003] The conventional method currently used in pulmonary vein CTA scanning is contrast agent tracking. The patient lies supine on the CT examination bed with both hands raised. An 18-20G indwelling needle is inserted into the right median cubital vein. The cardiac lead is connected to monitor the patient's electrocardiogram. The patient is trained to breathe. The scanning range is from the aortic arch to 1-2cm below the diaphragm. 100-120kV, automatic tube current modulation technology, prospective or retrospective scanning. After obtaining the positioning image, the ROI is placed at the maximum level of the left atrium, the trigger threshold is 100HU, and a monitoring scan is performed; a double-tube high-pressure syringe is used to inject intravenous contrast agent, the intravenous contrast agent concentration is 350-370mgl / ml, and the injection rate is 4-5ml / s; the amount of intravenous contrast agent used in adults is 50-70ml in the first phase, and 30ml of normal saline in the second phase. After the scan, the filling of the left atrium, pulmonary veins and left atrial appendage is observed. If a filling defect is found in the left atrial appendage, a second scan should be performed after a delay. After the second scan, observe whether the filling defect still exists. If the filling defect disappears, it is considered to be blood stasis. If the filling defect still exists, it is considered that there is a thrombus in the left atrial appendage. The disadvantage of this plan is that the patient needs to undergo two scans and receive two identical radiation doses. Summary of the invention

[0004] The present invention changes the injection scheme of iodine contrast agent and changes the delay time to before scanning, and can distinguish left atrial appendage blood circulation stasis or left atrial appendage thrombus through one scan, thereby reducing the number of scans and reducing the radiation dose of the patient. Based on this, the present invention is completed.

[0005] In a first aspect, an iodine contrast agent injection method for reducing the number of pulmonary vein CT scans is provided, wherein the injection method adopts a three-phase contrast agent injection method, and the method comprises the following steps:

[0006] Step 1: Injection of a mixture of iodine contrast medium and saline in the first phase;

[0007] Step 2: The second phase of iodine contrast agent injection should be started 40 seconds after the first phase of mixed solution injection;

[0008] Step 3: The third phase is injection of normal saline.

[0009] Furthermore, the injection dose of the mixed solution of iodine contrast agent and physiological saline is 30-50 ml.

[0010] Furthermore, the mixing ratio of the iodine contrast agent and the physiological saline mixture is 1:1.

[0011] Furthermore, the injection dose of the mixed solution of iodine contrast agent and normal saline is 40 ml.

[0012] Furthermore, the injection rate of the mixture of iodine contrast agent and physiological saline is 3 ml / s.

[0013] Furthermore, the injection dose of the second phase iodine contrast agent is 40 ml.

[0014] Furthermore, the injection rate of the second phase iodine contrast agent is 4-5 ml / s.

[0015] Furthermore, the injection dose of the third phase of normal saline is 30 ml.

[0016] Furthermore, the injection rate of the third phase of normal saline is 4-5 ml / s.

[0017] Furthermore, a scanning operation was performed while injecting normal saline during the third phase.

[0018] Beneficial Effects

[0019] Existing left atrium pulmonary vein CT examinations usually use delayed secondary scanning to distinguish left atrial appendage blood circulation stasis from left atrial appendage thrombosis. The present invention changes the iodine contrast agent injection scheme, changes the delay time to before the scan, and the viscosity of the first-phase mixed solution is lower than that of the iodine contrast agent stock solution, which is conducive to the filling of the left atrial appendage. Through a single scan, it is possible to distinguish left atrial appendage blood circulation stasis from left atrial appendage thrombosis, thereby reducing the number of scans and reducing the patient's radiation dose. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a CT image of the atrial appendage during the first phase of the existing iodine contrast agent injection regimen.

[0021] Figure 2 Time-delay scanning of atrial appendage CT images for existing iodine contrast agent injection schemes.

[0022] Figure 3 This is a CT image of the atrial appendage during the plain scan period before the third-phase contrast agent injection of the present invention.

[0023] Figure 4 This is a CT image of the atrial appendage during the three-phase contrast agent injection scheme of the present invention. DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention are further described below. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the embodiments described below can be combined with each other as long as they do not conflict with each other.

[0025] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are commercially available unless otherwise specified.

[0026] Example 1 Existing iodine contrast agent injection method

[0027] Patient inclusion criteria: patients with clinical diagnosis of atrial fibrillation who were prepared to undergo catheter ablation (CA) to isolate the pulmonary veins to treat atrial fibrillation were selected, with an age range of 18-80 years. Exclusion criteria: patients allergic to iodine contrast agents, patients with severe liver and kidney dysfunction, and all patients signed informed consent before scanning.

[0028] Scanning method: lying on the CT examination bed in supine position, with both hands raised, inserting a needle into the right median cubital vein, connecting the cardiac lead to monitor the patient's electrocardiogram, scanning range from the aortic arch to 1-2cm below the diaphragm, automatic tube current modulation technology, prospective or retrospective scanning. After obtaining the positioning image, the ROI is placed at the maximum level of the left atrium, the trigger threshold is 100HU, and the monitoring scan is performed.

[0029] Contrast agent injection method: The first phase injection of iodine contrast agent is 50-70ml, the iodine contrast agent concentration is 350-370mgl / ml, and the second phase is 30ml of normal saline, using a double-barreled high-pressure syringe for injection.

[0030] After the first-phase scan, observe the filling of the left atrium, pulmonary veins and left atrial appendage. If a filling defect is found in the left atrial appendage, a second scan should be performed after a delay. After the second scan, observe whether the filling defect still exists. If the filling defect disappears, it is considered to be blood stasis. If the filling defect still exists, it is considered that there is a thrombus in the left atrial appendage.

[0031] like Figure 1 As shown, the CT value of the first-stage left atrial appendage filling defect was 57HU, which was close to the blood CT value, and it could not be ruled out whether it was a thrombus. Figure 2 This is a delayed scan image after the first scan. The CT value of the original filling defect increased to 157HU, proving that blood entered the left atrial appendage after the delay and the original filling defect was blood stasis rather than thrombus.

[0032] Example 2 Contrast agent injection method of the present invention

[0033] Patient inclusion criteria: patients with clinical diagnosis of atrial fibrillation who were prepared to undergo catheter ablation (CA) to isolate the pulmonary veins to treat atrial fibrillation were selected, with an age range of 18-80 years. Exclusion criteria: patients allergic to iodine contrast agents, patients with severe liver and kidney dysfunction, and all patients signed informed consent before scanning.

[0034] Scanning method: lying on the CT examination bed in supine position, with both hands raised, inserting a needle into the right median cubital vein, connecting the cardiac lead to monitor the patient's electrocardiogram, scanning range from the aortic arch to 1-2cm below the diaphragm, automatic tube current modulation technology, prospective or retrospective scanning. After obtaining the positioning image, the ROI is placed at the maximum level of the left atrium, the trigger threshold is 100HU, and the monitoring scan is performed.

[0035] Contrast agent injection method: intravenous contrast agent is injected using a double-tube high-pressure syringe, and the iodine contrast agent concentration is 350-370mgl / ml. A three-stage contrast agent injection scheme is adopted: in the first stage, 40ml of iodine contrast agent and saline mixture (ratio 1:1, 20ml of iodine contrast agent and saline each) are injected, and the injection rate is 3ml / s; in the second stage, 40ml of iodine contrast agent is injected, and the injection rate is 4-5ml / s. The injection starts 40 seconds after the injection of the first stage mixture. After 10 seconds of injection, the monitoring is triggered at the left atrial level, with a threshold of 100HU. After reaching the threshold, the scan is started with a delay of 5 seconds; in the third stage, 30ml of saline, 4-5ml / s, and the scanning operation is performed while the saline is injected. The purpose of injecting the water mixture before scanning is to give the left atrial appendage enough filling time to replace the delay time after the first scan, so as to avoid a second scan.

[0036] Figure 3 This is a scan image without contrast agent injection. The CT value of the left atrial appendage at the same position after enhancement is 30HU. Figure 4In the images scanned using the three-phase contrast agent injection method of the present invention, the CT value of the position where the left atrial appendage was poorly filled (the same measurement position as the plain scan) increased to 179HU, proving that the poorly filled left atrial appendage was caused by blood circulation stasis rather than thrombosis, achieving the ability to identify left atrial appendage thrombus through the three-phase contrast agent injection method, avoiding the risk of increased radiation dose for patients receiving two scans.

Claims

1. A method for injecting iodine contrast agent to reduce the number of pulmonary vein CT scans, the injection method adopts a three-phase contrast agent injection method, and the method comprises the following steps: Step 1: Injection of a mixture of iodine contrast medium and saline in the first phase; Step 2: The second phase of iodine contrast agent injection should be started 40 seconds after the first phase of mixed solution injection; Step 3: The third phase is injection of normal saline.

2. The method according to claim 1, wherein the injection dose of the mixed solution of iodine contrast agent and physiological saline is 30-50 ml.

3. The method according to claim 2, wherein the mixing ratio of the iodine contrast agent and the physiological saline mixture is 1:

1.

4. The method according to claim 1, wherein the injection rate of the mixture of iodine contrast agent and physiological saline is 3 ml / s.

5. The method according to claim 1, wherein the injection dose of the second phase iodine contrast agent is 40 ml.

6. The method according to claim 1, wherein the injection rate of the second phase iodine contrast agent is 4-5 ml / s.

7. The method according to claim 1, wherein the injection dose of the third phase of normal saline is 30 ml.

8. The method according to claim 1, wherein the injection rate of the third phase of normal saline is 4-5 ml / s.

9. The method of claim 1, wherein the scanning operation is performed while injecting physiological saline during the third phase.

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