Non-contrast dual-energy CT iodine quantification for lung injury characterization after balloon pulmonary angioplasty

Abstract

Objectives This study aimed to identify differences in iodine concentrations in new-onset pulmonary injuries and normal lung parenchyma after balloon pulmonary angioplasty (BPA) for chronic thromboembolic pulmonary hypertension (CTEPH) using non-contrast dual-energy CT (NC-DECT) between patients with pulmonary hemorrhage and reperfusion pulmonary edema. Methods: Patients undergoing NC-DECT after BPA between January 2019 and April 2023 due to hemoptysis or clinical worsening were retrospectively evaluated for inclusion. Patients were divided based on the presence or absence of BPA-related hemoptysis. Intralesional iodine concentrations were measured in new-onset lung injuries, adjacent normal parenchyma, same lobe, and contralateral lung. CT morphological features, including lesion shape, imaging pattern, absolute density, and ROI size, were recorded. Statistical comparisons were performed using Mann-Whitney U, Friedman, and Wilcoxon signed-rank tests. Results: Thirteen patients with 32 new-onset post-BPA lung injuries were included. Median iodine concentration in lung injuries was significantly higher in patients with hemoptysis than those without (3.4 mg/mL versus 0.6 mg/mL; p < 0.001). In the hemoptysis group, iodine concentration in lung injuries was significantly higher compared with the different locations of normal lung parenchyma (p < 0.001). In the non-hemoptysis group, no significant differences in iodine concentration were observed between lung injuries and normal parenchyma (p = 0.167; p = 0.351; p = 0.246). Absolute density (p = 0.767), lesion shape (p = 0.610), imaging appearance (p = 0.530), ROI area (p = 0.452), and halo sign (p = 0.810) showed no significant correlation with hemoptysis. Conclusion: NC-DECT identifies iodine concentration differences in lung injuries between patients with and without hemoptysis after BPA. Elevated iodine concentrations may serve as an imaging marker for post-procedural pulmonary hemorrhage. Critical relevance statement: This exploratory study demonstrates the potential of NC-DECT in distinguishing between pulmonary hemorrhage and reperfusion pulmonary edema in lung injuries after BPA in patients with CTEPH. The ability to quantify iodine concentrations in lung lesions offers a novel imaging biomarker for pulmonary hemorrhage, which could play a pivotal role in improving clinical decision-making and management strategies for patients undergoing BPA.