PT - JOURNAL ARTICLE AU - Jens T. Bakker AU - Karin Klooster AU - Jan Bouwman AU - Gert Jan Pelgrim AU - Rozemarijn Vliegenthart AU - Dirk-Jan Slebos TI - Evaluation of spirometry-gated computed tomography to measure lung volumes in emphysema patients AID - 10.1183/23120541.00492-2021 DP - 2022 Jan 01 TA - ERJ Open Research PG - 00492-2021 VI - 8 IP - 1 4099 - http://openres.ersjournals.com/content/8/1/00492-2021.short 4100 - http://openres.ersjournals.com/content/8/1/00492-2021.full SO - erjor2022 Jan 01; 8 AB - Introduction In emphysema patient being evaluated for bronchoscopic lung volume reduction (BLVR), accurate measurement of lung volumes is important. Total lung capacity (TLC) and residual volume (RV) are commonly measured by body plethysmography but can also be derived from chest computed tomography (CT). Spirometry-gated CT scanning potentially improves the agreement of CT and body plethysmography. The aim of this study was to compare lung volumes derived from spirometry-gated CT and “breath-hold-coached” CT to the reference standard: body plethysmography.Methods In this single-centre retrospective cohort study, emphysema patients being evaluated for BLVR underwent body plethysmography, inspiration (TLC) and expiration (RV) CT scan with spirometer guidance (“gated group”) or with breath-hold-coaching (“non-gated group”). Quantitative analysis was used to calculate lung volumes from the CT.Results 200 patients were included in the study (mean±sd age 62±8 years, forced expiratory flow in 1 s 29.2±8.7%, TLC 7.50±1.46 L, RV 4.54±1.07 L). The mean±sd CT-derived TLC was 280±340 mL lower compared to body plethysmography in the gated group (n=100), and 590±430 mL lower for the non-gated group (n=100) (both p<0.001). The mean±sd CT-derived RV was 300±470 mL higher in the gated group and 700±720 mL higher in the non-gated group (both p<0.001). Pearson correlation factors were 0.947 for TLC gated, 0.917 for TLC non-gated, 0.823 for RV gated, 0.693 for RV non-gated, 0.539 for %RV/TLC gated and 0.204 for %RV/TLC non-gated. The differences between the gated and non-gated CT results for TLC and RV were significant for all measurements (p<0.001).Conclusion In severe COPD patients with emphysema, CT-derived lung volumes are strongly correlated to body plethysmography lung volumes, and especially for RV, more accurate when using spirometry gating.CT-derived lung volumes in severe emphysema patients are strongly correlated to lung volumes measured by body plethysmography and spirometry gating in CT helps to improve agreement with body plethysmography results https://bit.ly/3DFvqmf