Mathieu Lederlin, Presenter: Nothing to Disclose

Francois H. Laurent MD, Abstract Co-Author: Nothing to Disclose

Yann Portron, Abstract Co-Author: Nothing to Disclose

Olivier Corneloup MD, Abstract Co-Author: Nothing to Disclose

Patrick Berger MD, PhD, Abstract Co-Author: Nothing to Disclose

Michel Montaudon MD, Abstract Co-Author: Nothing to Disclose

Computed tomography (CT) assessment of airway wall thickening is validated as a marker of remodeling in chronic obstructive pulmonary disease (COPD). However it is currently not used in routine practice due to the complexity of airway segmentation algorithms. COPD phenotyping using CT may benefit from a more straightforward technique based upon physical properties of tissues. The objectives of this study were to evaluate bronchial wall attenuation value (WAV) in smokers with and without COPD as compared to usual morphometric parameters, and to correlate WAV with pulmonary function.

Using CT, WAV and morphometric parameters derived from bronchial lumen and wall area were averaged over 4 bronchi in smokers with COPD (n=30), smokers without COPD (n=30) and control subjects (n=30).Variability of measurements was analyzed. Subject characteristics, pulmonary function tests and CT results were compared between groups. Ability of each CT parameter in predicting patients’ group was assessed using receiver operating characteristics (ROC) curves and areas under the curve (AUC) were compared. Correlation coefficients were determined between CT parameters and PFT results. Finally, stepwise multiple regressions were performed to determine which parameters influenced both WAV and FEV1.  

WAV was the only CT parameter allowing to separate each pair of groups. Mean values of WAV were: -293±71 HU in smokers with COPD, -387±70 HU in smokers without COPD, and -457±69 HU in control subjects. AUC of WAV for separating smokers with and without COPD was greater than that of any morphometric parameter and not different from that of forced expiratory volume in 1 second (FEV1). WAV was correlated to all function tests and to bronchial morphometry. In a model of stepwise forward multiple regression using FEV1 as the dependant variable, WAV demonstrated a change in R² of 0.443 when morphometric parameters were responsible for a change of 0.055.

WAV appears to be a more powerful index than bronchial morphometry for assessing tobacco-related bronchial wall changes. It is a promising tool for non-invasive phenotyping of COPD patients and follow-up of bronchial wall changes in smokers.

Bronchial wall attenuation appears to be more powerful and reproducible than usual morphometric parameters. It is a promising tool to achieve non-invasive phenotyping and follow-up of COPD patients.

Lederlin, M, Laurent, F, Portron, Y, Corneloup, O, Berger, P, Montaudon, M, Airway Wall Attenuation as a Biomarker in COPD: Feasibility and Comparison with Morphometric Parameters.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9002746.html