Pulmonary Perfusion Changes as Assessed by Contrast-Enhanced Dual-Energy Computed Tomography after Endoscopic Lung Volume Reduction by Coils

Abstract

Background: Endoscopic lung volume reduction by coils (LVRC) is a recent treatment approach for severe emphysema. Furthermore, dual-energy computed tomography (DECT) now offers a combined assessment of lung morphology and pulmonary perfusion. Objectives: The aim of our study was to assess the impact of LVRC on pulmonary perfusion with DECT. Methods: Seventeen patients (64.8 ± 6.7 years) underwent LVRC. DECT was performed prior to and after LVRC. For each patient, lung volumes and emphysema quantification were automatically calculated. Then, 6 regions of interest (ROIs) on the iodine perfusion map were drawn in the anterior, mid, and posterior right and left lungs at 4 defined levels. The ROI values were averaged to obtain lung perfusion as assessed by the lung's iodine concentration (C_Lung, μg·cm^-3). The C_Lung values were normalized using the left atrial iodine concentration (C_LA) to take into account differences between successive DECT scans. Results: The 6-min walk distance (6MWD) improved significantly after the procedure (p = 0.0002). No lung volume changes were observed between successive DECT scans for any of the patients (p = 0.32), attesting the same suspended inspiration. After LVRC, the emphysema index was significantly reduced in the treated lung (p = 0.0014). Lung perfusion increased significantly adjacent to the treated areas (C_Lung/C_LA from 3.4 ± 1.7 to 5.6 ± 2.2, p < 0.001) and in the ipsilateral untreated areas (from 4.1 ± 1.4 to 6.6 ± 1.7, p < 0.001), corresponding to a mean 65 and 61% increase in perfusion, respectively. No significant difference was observed in the contralateral upper and lower areas (from 4.4 ± 1.9 to 4.8 ± 2.1, p = 0.273, and from 4.9 ± 2.0 to 5.2 ± 1.7, p = 0.412, respectively). A significant correlation between increased 6MWD and increased perfusion was found (p = 0.0027, R² = 0.3850). Conclusions: Quantitative analysis based on DECT acquisition revealed that LVRC results in a significant increase in perfusion in the coil-free areas adjacent to the treated ones, as well as in the ipsilateral untreated areas. This suggests a possible role for LVRC in the improvement of the ventilation/perfusion relationship.

Identifying Responders and Exploring Mechanisms of Action of the Endobronchial Coil Treatment for Emphysema

“…This difference could be caused by the extreme low baseline physical activity levels in the other study, with only 2 days of measurement compared to 7 and the shorter follow-up after coil treatment (6 vs. 12 weeks). We also did not find a change in perfusion in the (un)treated lobes, while Lador et al [32] did find an improvement in perfusion in the untreated lobes after treatment. This difference could be caused by the fact that they measured perfusion by dual-energy computed tomography.…”

Bronchoscopic lung volume reduction: recent updates

“…Complications in the coil group compared to conventional therapy were more common (OR 2.14, 95% CI: 1.41-3.23) (5) Lador et al (26) studied pulmonary perfusion prospectively in 17 patients treated with coils, and showed the potential benefit of coils in improving ventilationperfusion matching. Contrast-enhanced dual-energy computed tomography (DECT) scans were utilized before and after coil treatment, and pulmonary perfusion was noted to significantly improve in areas next to coil placement and in coil-free areas within the same lung, with a mean perfusion increase of 65% and 61% perfusion respectively.…”