Statistical method
Continuous variables were described as the as mean ± SD for normally distributed data and median (25–75% quartile) for non-normally distributed data. The comparison between the two groups was performed by two independent samples t-test, and the counting data was analyzed by chi-square test. Using the pulmonary venography as the gold standard, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated including the 95% confidence interval (CI) based on a binomial distribution. All tests were 2-tailed, and a statistical significance was established at P < 0.05. All analyses were performed using SPSS software (version 27.0 SPSS, Inc., Chicago) (Fig. Flowchart of this study.