A novel method of estimating small airway disease using inspiratory-to-expiratory computed tomography

Respiration Aug 29, 2017

Kirby M et al. – This study evaluated small airway diseases utilizing a novel computed tomography (CT) inspiratory–to–expiratory approach known as disease probability measure (DPM) and its correlation with pulmonary function. It was observed that pulmonary function and symptoms have a significant correlation with CT inspiratory–to–expiratory gas trapping measurements. However, additional investigations are needed to confirm the quantitative and spatial differences between parametric response map (PRM) and DPM classification.


  • Participants from the CanCOLD study were assessed with full–inspiration/full–expiration CT and pulmonary function measurements.
  • Voxel images were classified based on PRM and DPM as emphysema, gas trapping (GasTrap) related to functional small airway disease, or normal.


  • Participants were classified as never–smokers (n = 135), at risk (n = 97), Global Initiative for Chronic Obstructive Lung Disease I (GOLD I; n = 140), and GOLD II chronic obstructive pulmonary disease (n = 96).
  • PRMGasTrap and DPMGasTrap measurements were significantly elevated in GOLD II versus never–smokers and at risk and in GOLD I versus at risk.
  • Based on DPM classification, the gas trapping measurements were markedly higher in GOLD II versus GOLD I.
  • More voxels were classified as gas trapping by DPM than by PRM.
  • Both DPM and PRMGasTrap measurements were significantly associated with forced expiratory volume in 1 second (FEV1), FEV1/forced vital capacity, residual volume/total lung capacity, bronchodilator response, and dyspnea.

Go to Original

Sign-up to continue reading. It is free & takes less than 2 mins

  • 45 lakhs+ doctors trust M3 globally

  • Nonloggedininfinity icon
    Free & unlimited access to original articles and quizzes
  • Nonloggedinlock icon
    Secure: we never sell your data
This article is only available to members. Are you a doctor? Click here to signup for free.
M3 app logo
Choose easy access to M3 India from your mobile!

M3 instruc arrow
Add M3 India to your Home screen
Tap  Chrome menu  and select "Add to Home screen" to pin the M3 India App to your Home screen