| Pulmonary embolism(PE)is a common acute and critical disease in clinical work.Computed tomography pulmonary angiography(CTPA)is the first choice for the diagnosis of PE.However,the CTPA scanning scheme is not unified,according to different scanning phases,there are two examination schemes in clinical work: single phase computed tomography pulmonary angiography(SP-CTPA)and dual phase computed tomography pulmonary angiography(DP-CTPA).Sp-ctpa is used by most general hospitals for its simple operation and low radiation.DP-CTPA is used by most cardiovascular hospitals and a few general hospitals to identify PE,pulmonary insufficiency artifacts(PIA)and systemic pulmonary shunt artifacts(S-PSA).The diagnostic efficiency of two different examination schemes in diagnosing PE.The applicability and whether the difference between the two examination schemes due to the presence of PIA and S-PSA is statistically significant have not been reported in the literature.In order to better select the examination scheme in the clinical work,this study conducted the clinical application research of SP-CTPA and DP-CTPA in diagnosing PE from the following three parts:Part 1 Comparative Study of Diagnostic Efficacy of Single Phase and Dual Phase Computed Tomography Pulmonary Angiography in the Diagnosis of Pulmonary EmbolismObjective We compared the efficacy of single phase-computed tomography pulmonary angiography(SP-CTPA)and dual phase-computed tomography pulmonary angiography(DP-CTPA)for the diagnosis of pulmonary embolism(PE).Methods We recruited 1019 consecutive patients(359 with PE)who underwent DP-CTPA(phase I: pulmonary artery phase;phase II: aortic phase)for suspected PE between January and October 2021.Phase I of DP-CTPA was used as SP-CTPA,and the final clinical diagnosis(FCD)was used as the gold standard.Results 352 cases of PE were detected by both methods,with the same sensitivity of 98.1%(99.6–99.5%).Using SP-CTPA,142 cases [13 pulmonary insufficiency artifacts(PIA)and 129 systemic-pulmonary shunt artifacts(S-PSA)] were false-positive with specificity of 78.5%(75.3–81.6%).No false-positive was found with DP-CTPA,with specificity of 100%,positive predictive value of 1,and negative predictive value of 0.990(Net Reclassification Improvement=0.215;P<0.05).According to FCD,the positive results of SP-CTPA were divided into PIA,S-PSA,and true-positive(TPSP-CTPA)groups,and pairwise comparisons were performed.The bronchiectasis and hemoptysis rate in S-PSA group was higher than that in PIA and TP groups(P<0.001),and the pulmonary hypertension(PH)rate in PIA group was higher than that in S-PSA and TP groups(P<0.001).Conclusion The diagnostic efficiency of DP-CTPA for the diagnosis of PE was high.SP-CTPA may misdiagnose PIA(common in patients with PH)and S-PSA(common in patients with bronchiectasis and hemoptysis)as PE.Part 2 Pilot Study on the Mechanism and Clinical Characteristics of Artifacts in Pulmonary InsufficiencyObjective In this study,we aimed to preliminarily explore the mechanisms of artifacts caused by pulmonary insufficiency in Suspected PE patients complicated with pulmonary hypertension,and to find the clinical factors that can be used in clinical work to predict the patients with pulmonary insufficiency,to select the appropriate CT pulmonary angiography scanning scheme in clinical work.Methods From January 2020 to December 2021,patients with pulmonary hypertension who underwent DP-CTPA due to clinical symptoms and suspected PE in our hospital were continuously collected in this study.They were divided into two groups according to whether there were PIA.Nine clinical factors potentially affecting pulmonary artery filling were collected,including two patients’ own factors(age and gender)Two clinical symptoms(chest pain,dyspnea),one laboratory test(D-dimer level)and four right cardiac catheter data(m PAP,PAWP,PVR and CI)were used to find the clinical factors that can predict PIA through univariate and multivariate analysis.Results Univariate analysis showed that gender,dyspnea,PAWP,PVR and CI were associated with pulmonary insufficiency(P < 0.05);Multivariate logistic further confirmed that severe low cardiac index(CI ≤ 2.0L / min · m2)and PAWP ≥ 14.8mmhg were independent risk factors for predicting PIA(P <0.05).Conclusion 1.The clinical characteristics of patients with PIA are decompensated patients with pulmonary hypertension;CI ≤ 2.0L / min · m2 and PAWP ≥ 14.8mmhg were independent predictors of PIA;when patients with suspected PE have severe low cardiac index(CI ≤ 2.0L / min · m2)and / or PAWP ≥ 14.8mmhg,DP-CTPA scanning should be selected to avoid misdiagnosis of PIA as PE.Part3 The Clinical Prediction Model of Systemic-Pulmonary Shunt ArtifactsObjective to construct and evaluate the clinical prediction model of the risk of S-PSA in patients with suspected PE,to facilitate the selection of appropriate CTPA in clinical work.Methods From January to December 2021,1355 patients with suspected PE underwent DP-CTPA examination in our hospital,including 152 patients with S-PSA and 1203 patients without S-PSA.According to the CT examination time,they were divided into training set(1006 cases)and verification set(349cases).Based on the independent influencing factors of S-PSA obtained from multifactor logistic regression model,the nomogram scoring system was established,the C index was calculated,and the calibration curve and decision curve were drawn to evaluate the model.Results Univariate logistic analysis showed that chest pain,hemoptysis,elevated D-dimer,and bronchiectasis were associated with S-PSA(P < 0.05).Multivariate logistic analysis showed that chest pain,hemoptysis,elevated D-dimer,bronchiectasis,pulmonary infection were independent predictors of S-PSA.Nomograms for predicting the risk of S-PSA show acceptable consistency and calibration ability in training and validation sets.Conclusion Chest pain,hemoptysis,elevated D-dimer,bronchiectasis,and pulmonary infection are independent predictors of S-PSA in patients with suspected PE.The nomogram prediction model of S-PSA based on independent predictors is of application value in single center verification. |
