General information
In total we identified 30 patients in our hospital who underwent CTPA examination and diagnosed PE in our hospital from January 2015 to December 2020, and received anticoagulant or thrombolytic therapy, and then perform the second CTPA examination 1–3 months after treatment.At the same time collecting some clinical indexes related to coagulation function and cardiac function injury within 24h before and after CTPA examination. Among them, there were 18 males and 12 females, aged 13–83 years old, with an average of (52.67 ± 16.67). There has been no serious heart and pulmonary vascular disease and liver and kidney damage. The study was approved by the Institutional Review Board of the hospital, and informed consent was obtained from each patient.
Equipment
CTPA examination equipment: Philips brilliance ICT 256 slice spiral CT and EBW workstation Evaluate the patient’s physical condition before the examination, perform routine iodine allergy tests, and introduce the purpose, methods and precautions of the CTPA examination to the patient or their family members, and sign an informed consent form. Instruct the patient to carry out breath-holding training. Each breath-holding time is more than 10s. The patient is placed in a supine position, holding the head with both hands, and the scanning direction is from foot to head.
Scanning range: chest entrance to diaphragm level.
The scanning parameters are as follows: tube voltage 120kv, current 250mAs, 0.5s/turn, pitch 0.625, inject iopromide (Uvixine (350mgI/ml)) through the anterior elbow vein with a double-barreled high-pressure syringe, the injection rate is 5ml/s, the total dose is 60-80ml, after the contrast agent is injected, the same flow rate is injected with the same flow rate of 0.9% sodium chloride 30ml. The delay time is based on the artificial intelligence trigger scan, the position is set in the main lung, and the pulse trigger threshold is set to 100HU. After scanning, the reconstructed image has a layer thickness of 0.625mm and a layer spacing of 0.625mm.The data are transmitted to the post EBW processing workstation for analysis.
Statistics indicators
Using Qanadli embolism index[5], the calculation method is as follows, according to the two lungs are divided into 10 pulmonary segment arteries, a partial pulmonary artery blockage is counted as 1, the complete blockage is counted as 2, and when no emboli is found, it is counted as 0. Embolism in sub-segment pulmonary artery is calculated based on partial blockage of corresponding pulmonary artery, The embolism in the artery above the pulmonary artery is equal to the total number of its branch pulmonary artery. For example, partial embolism of upper lobe pulmonary artery was 3 points, complete embolism was 6 points, right middle lobe and left lingual lobe pulmonary artery embolism was 2 or 4 points, bilateral lower lobe pulmonary artery embolism was 5 or 10 points, bilateral main pulmonary artery embolism was 10 or 20 points, main pulmonary artery embolism was 20 points, maximum occlusion score was 40 points. Therefore, Qanadli embolism index = ∑(n×d)/40×100%, where n represents the location of the obstruction with emboli, and d represents the degree of obstruction score.
Measure the maximum distance from the ventricular septum to the inner side of the free wall of the ventricle on the patient’s CTPA axial image, that is, the diameter of the largest short axis of the ventricle, and calculate the ratio of the maximum short axis diameter of the right ventricle to the maximum short axis diameter of the left ventricle (RVd/ LVd), simultaneously measure the diameter of the ascending aorta (AAd), the diameter of the main pulmonary artery (MPAd), the diameter of the right pulmonary artery (RPAd), and the diameter of the left pulmonary artery (LPAd), and calculate the diameter of the ascending aorta (AAd) and the diameter of the main pulmonary artery (MPAd) ) Ratio (AAd/MPAd).
Collect the clinical indicators required within 24 hours before and after the CTPA examination of the patient, including serum D-dimer, N-terminal B-type natriuretic peptide precursor (NT-proBNP), cardiac troponin I (cTnI), myocardial enzyme profile (aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK).
Statistical analysis of data
CT PAOI and CTPA right heart function parameters were completed by two senior diagnostic imaging physicians who read the CTPA images of the patient without knowing the clinical data of each patient, independently and blindly. The final results are subject to the consensus of the two physicians. Statistical analysis uses SPSS23.0 statistical software to analyze the data. The measurement data is expressed as x ± s and [M(P25,P75)]. The K-S test is used to determine whether the measurement data conforms to the normal distribution. the two paired sample t test is used for those conforming to the normal distribution, and the nonparametric Wilcoxon signed rank sum test is used for those not conforming to the normal distribution, with P < 0.05 as the difference is statistically significant. Spearman rank correlation coefficient was used to evaluate the correlation between CT PAOI and RVd / LVd, AAd, MPAd, D-dimer, cTnI, NT-proBNP, AST, LDH, CK.