Abstract
Introduction: Determining accurate emphysema scores (ES) is important in COPD patient evaluation for lung volume reduction. ES can be influenced by CT parameters, especially choice of image reconstruction kernel. Earlier studies have demonstrated that sharp kernels may lead to an overestimation of the ES. CT parameters for ES are not yet fully standardized.
Aim: To demonstrate the effects of kernel choice on the ES in severe COPD patients.
Methods: Severe COPD patients evaluated for bronchoscopic lung volume reduction treatment were included. Patients were breath-coached to maximum inspiration at CT acquisition. Scans were reconstructed with three different kernels: B31f (smooth), B45f (medium smooth) and B60f (sharp), and ES compared using repeated measures ANOVA. Bland-Altman plots assessed the proportional bias.
Results: ES from CT of 98 patients were analysed. The mean ES for the smooth kernel had a significantly lower mean from the medium smooth and sharp kernel (figure). Bland-Altman plots revealed that low ES in smooth kernels increased in sharp kernels, while high ES in soft kernels decreased in sharp kernels.
Conclusions: Both over- and underestimation of emphysema is demonstrated due to kernel choice in severe COPD patients. To ensure an accurate ES, the scan protocol should be standardized, and/or the CT scans should be normalized. This would be especially important for lung volume reduction treatment screening.
Footnotes
Cite this article as Eur Respir J 2022; 60: Suppl. 66, 2934.
This article was presented at the 2022 ERS International Congress, in session “-”.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2022
