BackgroundSmall airways are regarded as the elective anatomic site of obstruction in most chronic airway diseases. Expiratory computed tomography (CT) is increasingly used to assess obstruction at this level but there is no consensus regarding the best quantification method. We aimed to evaluate software-assisted CT quantification of air trapping for assessing small airway obstruction and determine which CT criteria better predict small airway obstruction on single breath nitrogen test (SBNT).MethodsEighty-nine healthy volunteers age from 60 to 90 years old, underwent spirometrically-gated inspiratory (I) and expiratory (E) CT and pulmonary function tests (PFTs) using SBNT, performed on the same day. Air trapping was estimated using dedicated software measuring on inspiratory and expiratory CT low attenuation area (LAA) lung proportion and mean lung density (MLD). CT indexes were compared to SBNT results using the Spearman correlation coefficient and hierarchical dendrogram analysis. In addition, receiver operating characteristic (ROC) curve analysis was performed to determine the optimal CT air-trapping criterion.Results43 of 89 subjects (48,3%) had dN2 value above the threshold defining small airway obstruction (i.e. 2.5% N2/l). Expiratory to inspiratory MLD ratio (r = 0.40) and LAA for the range −850 -1024 HU (r = 0.29) and for the range −850 -910 HU (r = 0.37) were positively correlated with SBNT results. E/I MLD was the most suitable criterion for its expression. Expiratory to inspiratory MLD ratio (E/I MLD) showed the highest AUC value (0.733) for small airway obstruction assessment.ConclusionAmong all CT criteria, all correlating with small airway obstruction on SBNT, E/I MLD was the most suitable criterion for its expression in asymptomatic subjects with mild small airway obstructionTrial registrationRegistered at Clinicaltrials.gov, identifier: NCT01230879.

BAE with EVAC seems to be feasible and safe with immediate control of hemoptysis in most patients. The postinjection fluoroscopic visibility of EVAC under fluoroscopy was inferior to CT.

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Airway remodelling inducing structural and functional decline is a main factor leading to clinical disablement in chronic obstructive pulmonary disease (COPD) [1]. However, whether airway remodelling is also a potential feature of the normal healing process in ordinary lifelong environmental exposure and chronic endogen damage due to senescence is not well elucidated [2]. The relationship between ageing and development of COPD is complex. On one hand, while there is a higher prevalence of COPD in the elderly, ageing is not the direct cause of COPD; on the other hand, it does increase the susceptibility of the lung to extrinsic damage [3].To avoid misinterpretation in chest computed tomography (CT) analysis, physiological, age-related changes [4] should be recognised. Thus, the purpose of this prospective study was to evaluate whether airway remodelling resulting from the normal ageing process can be assessed in vivo using software-assisted CT quantification, with correlation to pulmonary function testing (PFT).This study was conducted with the approval of the local research ethics committee. Participants were required to be asymptomatic, aged from 60 to 90 years, and nonsmokers for ⩾20 years, with a cumulative history of <10 pack-years of tobacco use.