Precision in Pulmonary Embolism Diagnosis: Leveraging D-dimer Levels With Computed Tomography Pulmonary Angiography (CTPA) Insights

Abstract

Introduction Pulmonary embolism (PE) remains a critical condition requiring timely diagnosis and treatment. The use of D-dimer, a fibrin degradation product, as a biomarker, combined with computed tomography pulmonary angiography (CTPA), is a common practice in diagnosing PE. Aim This study aims to increase diagnostic accuracy for PE by relating the D-dimer levels to the findings on CTPA. Specifically, it aims to calculate the sensitivity and specificity of D-dimer levels against CTPA results and also establish the association of D-dimer levels with the location of the PE. Methods This retrospective analysis was conducted at a tertiary care hospital, including patients who underwent CTPA and had D-dimer levels recorded over a one-year period. The total sample size was 124. D-dimer levels were categorized into four groups based on CTPA findings: Category 0 (no PE), Category I (peripheral PE), Category II (PE in lobar arteries), and Category III (central embolisms in the pulmonary trunk or arteries). Statistical analyses were performed to evaluate the correlation between D-dimer levels and CTPA findings, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results The study found that Category 0 (no PE) had an average D-dimer of 3.6 mg/L, Category I (peripheral PE) had 4.3 mg/L, Category II (PE in lobar arteries) had 3.6 mg/L, and Category III (central embolisms) had 7.1 mg/L. The sensitivity of D-dimer in predicting PE was 1.0, and the specificity was 0.2. The PPV was 0.3208, and the NPV was 1.0. These findings indicate a significant correlation between elevated D-dimer levels and the presence of PE. Conclusion Integrating D-dimer levels with CTPA findings can improve diagnostic accuracy and efficiency for PE. Establishing reliable D-dimer cutoff values may help clinicians better stratify patient risk and make informed decisions about the need for imaging, thereby optimizing resource utilization and minimizing unnecessary CTPA scans. This study highlights the potential benefits of combining biomarker analysis with imaging results in the clinical management of PE.

Keywords: central embolism; computed tomography pulmonary angiography; d-dimer levels; lobar arteries; pulmonary embolism.

Figure 1. Distribution of pulmonary embolism instances across different categories.

Based on the provided details regarding the CTPA results and their classification into four categories of pulmonary embolism (PE), here is a revised legend for the image: (1) no pulmonary embolism (Category 0) represents instances where no pulmonary embolism is detected, totaling 92 cases; (2) peripheral pulmonary embolism (Category I) indicates seven instances where pulmonary embolism is found in the peripheral regions of the lungs; (3) lobar pulmonary embolism (Category II) includes 10 cases where the embolism is located in the lobar branches of the pulmonary arteries; (4) central pulmonary embolism (Category III) reports 15 instances where the pulmonary embolism is located in the central pulmonary trunk or arteries.