Grant: Travel Awards - Institute Community Support

Background & Purpose: Studies in explanted lungs show remodeling/destruction of the terminal bronchioles (TB) occurs before emphysema in patients with chronic obstructive lung disease (COPD). Using in vivo computed tomography (CT), we hypothesize that reduced CT total airway count (TAC) predicts TB remodeling/destruction and emphysema measured using micro-CT. Methods: CT and micro-CT were acquired in lungs from GOLD-IV COPD (n=8) patients after lung transplantation and unused donor lungs (n=7). Each lung was inflated with air and frozen solid. CT was performed on the inflated and frozen lungs and TAC was generated (VIDA Diagnostics, Inc). The lungs were cut and cores of tissue were removed for micro-CT; mean linear intercept (Lm), number of TB/ml lung (nTB), TB lumen circularity (TBcirc) and number of alveolar attachments/length of outer perimeter (adjustedAA) were measured. Results: COPD patients were former smokers with mean age at transplant=56±6years, pack-years=36±10 and FEV1=25±8%pred. CT TAC was significantly associated with Lm (r=-52, p=0.048), TBcirc (r=0.53, p=0.04) and adjustedAA (r=0.53, p=0.04), but there was no association between TAC and nTB (r=0.44, p=0.10). Conclusions: CT TAC predicts disease changes in the 'quiet' zone in COPD. In these patients with very severe COPD, TAC reflects emphysematous destruction and distortion of the remaining TB.