PT  - JOURNAL ARTICLE
AU  - Ruth Hartley
AU  - Bethan Barker
AU  - Mini Pakkal
AU  - Aparna Desphande
AU  - Chris Brightling
AU  - Sumit Gupta
TI  - Quantitative computed tomography (QCT) measured 5<sup>th</sup> generation airways, emphysema and airflow obstruction in chronic obstructive pulmonary disease (COPD) from a COPDMAP cohort
DP  - 2014 Sep 01
TA  - European Respiratory Journal
PG  - P641
VI  - 44
IP  - Suppl 58
4099  - http://erj.ersjournals.com/content/44/Suppl_58/P641.short
4100  - http://erj.ersjournals.com/content/44/Suppl_58/P641.full
SO  - Eur Respir J2014 Sep 01; 44
AB  - Background: Airflow obstruction in COPD is due to small airway obliteration and emphysema. QCT can be used to measure airway geometry in airways bigger than 2mm diameter. Whether the absence of visible 5th generation airways is associated with airflow obstruction and emphysema is unknown.Aims: Use QCT to describe presence and size of 5th generation segmental airways and explore relationships with lung function in COPD.Methods: COPD MAP subjects underwent low dose thoracic CT (Siemens 16) and spirometry. Fully automated software (Apollo,VIDA Diagnostics, Iowa) was used for post processing of CT scans. Patients were divided into 2 groups according to whether or not 15 or more 5th generation segmental bronchi were visualised by CT. Spirometry was correlated with QCT measured emphysema (Percentile 15) and airway morphometry (mean percentage wall area [%WA]) for 5th generation airways).Results: 86 patients were recruited; 67% male, 81% ex-smokers, with mean (SEM) age 69(1) years, and post-bronchodilator FEV1 % predicted and FEV1/FVC ratio of 54(2)% and 52(1)% respectively. Subjects with 15 or more 5th generation airways visible had higher mean (SEM) FEV1 % predicted (57[2]% versus 48[3]% ; p=0.024) and less severe QCT determined emphysema (-959.03[2.51] versus -972.47[3.93]; p<0.005) than those with<15 small airwaysDiscussions: In COPD obliteration of smaller airways determined from QCT reconstructed airways is associated with more airflow obstruction and emphysema. The role of QCT in evaluating small airways disease, and the clinical implications of these observations require further investigation.