Thorax 65:775-781 doi:10.1136/thx.2010.136374
  • Asthma

Quantitative analysis of high-resolution computed tomography scans in severe asthma subphenotypes

Open Access
  1. Christopher E Brightling1
  1. 1Institute for Lung Health, Department of Infection, Inflammation and Immunity, University of Leicester, Leicester, UK
  2. 2Glenfield Hospital, Leicester, UK
  1. Correspondence to Professor Christopher E Brightling, Institute for Lung Health, University of Leicester, Leicester LE3 9QP, UK; ceb17{at}
  • Received 23 February 2010
  • Accepted 22 May 2010


Background Severe asthma is a heterogeneous condition. Airway remodelling is a feature of severe asthma and can be determined by the assessment of high-resolution computed tomography (HRCT) scans. The aim of this study was to assess whether airway remodelling is restricted to specific subphenotypes of severe asthma.

Methods A retrospective analysis was performed of HRCT scans from subjects who had attended a single-centre severe asthma clinic between 2003 and 2008. The right upper lobe apical segmental bronchus (RB1) dimensions were measured and the clinical and sputum inflammatory characteristics associated with RB1 geometry were assessed by univariate and multivariate regression analyses. Longitudinal sputum data were available and were described as area under the time curve (AUC). Comparisons were made in RB1 geometry across subjects in four subphenotypes determined by cluster analysis, smokers and non-smokers, and subjects with and without persistent airflow obstruction.

Results Ninety-nine subjects with severe asthma and 16 healthy controls were recruited. In the subjects with severe asthma the RB1 percentage wall area (%WA) was increased (p=0.009) and lumen area (LA)/body surface area (BSA) was decreased (p=0.008) compared with controls but was not different across the four subphenotypes. Airway geometry was not different between smokers and non-smokers and RB1 %WA was increased in those with persistent airflow obstruction. RB1 %WA in severe asthma was best associated with airflow limitation and persistent neutrophilic airway inflammation (model R2=0.27, p=0.001).

Conclusions Airway remodelling of proximal airways occurs in severe asthma and is associated with impaired lung function and neutrophilic airway inflammation.


  • Funding The Wellcome Trust (Senior Clinical Fellowship, CEB).

  • Competing interests CEB has received research grants from MedImmune, AstraZeneca and GlaxoSmithKline and fees for consulting and/or speaking from MedImmune, AstraZeneca, GlaxoSmithKline, Novartis, Aerovant and Genentech. AJW has received research grants from GlaxoSmithKline and Pfizer and is on GlaxoSmithKline advisory board on asthma and related diseases. PH has received an unrestricted educational grant from GlaxoSmithKline. All other authors declare that they have no competing interests of relevance to this manuscript. No pharmaceutical company had any involvement in the planning, design, analysis or interpretation of the current study.

  • Ethics approval This study was conducted with the approval of the Leicestershire, Northamptonshire and Rutland research ethics committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Received 23 February 2010
  • Accepted 22 May 2010

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