Purpose: Computed tomography pulmonary angiography (CT-PA) is the diagnostic modality used for pulmonary embolism (PE). This study aimed to estimate the positive CT-PA rate and identify the predictors of positive CT-PA results.
Methods: A retrospective observational study was conducted by examining the CT-PA data for ruling out PE in all adult patients who visited the King Fahd Hospital of Imam Abdulrahman Bin Faisal University. The data regarding background demographic information, clinical information, and CT-PA findings were collected from electronic health records. Data were analyzed descriptively using the chi-squared test. Multivariate regression analysis was used to identify the predictors of positive CT-PA results.
Results: In total, 548 patients (209 male, 339 female) who underwent CT-PA scans were included. The positive CT-PA rate was 18.8%. The Charlson Comorbidity Index was not significantly associated with positive CT-PA results (p = 0.456). Multivariate logistic regression analysis revealed that smoking (odds ratio [OR] 4.96; 95% confidence interval [95% CI] 2.05-12.02) was an independent factor associated with positive CT-PA results. The CT-PA scans performed in winter and spring were 43% (OR 0.43; 95% CI 0.22-0.84) and 52% (OR 0.52; 95% CI 0.28-0.97) less likely to show positive results compared with those performed in autumn, respectively.
Conclusion: The positive CT-PA rate varied significantly between seasons. Smoking was a predictor of positive CT-PA results. These findings may assist in developing interventions for improving the utilization of CT-PA scans to avoid unnecessary exposure of patients to radiation.
Clinical trial registration: N/A.
Keywords: Charlson Comorbidity Index; Computed tomography pulmonary angiography; Diagnostic yield; Positive rate; Pulmonary embolism; Seasonal variation.