Maxime Hackx MD, Presenter: Nothing to Disclose

Elodie Gyssels, Abstract Co-Author: Nothing to Disclose

Isabelle De Meulder, Abstract Co-Author: Nothing to Disclose

Marie Bruyneel, Abstract Co-Author: Nothing to Disclose

Alain Van Muylem, Abstract Co-Author: Nothing to Disclose

Stephane Alard, Abstract Co-Author: Nothing to Disclose

Vincent Ninane, Abstract Co-Author: Nothing to Disclose

Pierre Alain Gevenois MD, Abstract Co-Author: Nothing to Disclose

Variability is a limitation to the incorporation of quantitative CT analysis of airways in COPD patients in daily practice. As bronchodilation minimizes the variability of spirometric measurements in COPD patients, we prospectively tested the hypothesis that post-bronchodilation CT measurements of airways are less variable than pre-bronchodilation measurements. If less variable, post-bronchodilation measurements would thus require considering fewer airways than pre-bronchodilation measurements.

This study was approved by our ethical committee and informed consent was obtained. Twenty patients (16 men; mean age, 66 yrs ± 8) with no exacerbation or infection episode in the four previous weeks were included. Pre- and post-bronchodilation CT and PFT were performed on the same day, 48 hours after treatment withholding. With dedicated software, luminal area (LA) and wall thickness (WT) of 3rd and 4th generations airways were measured twice by an observer blinded to the bronchodilation status. The percentage of total airway area occupied by the wall (WA%) and the square root of wall area at an internal perimeter of 10 mm (√WAPi10) were calculated. Mean values and variances of pre- and post-bronchodilation LA, WT, WA%, and √WAPi10 were compared.

Significant differences between the two reading sessions were observed for LA (P<.001), WT of 4th generation airways (P=.028) and WA% (P<.001), but not for WT of 3rd generation airways (P=.728) or √WAPi10 (P=.162). Mean LA and WA% were respectively higher and lower after bronchodilation than before (P<.001 and <.010, respectively), without difference for WT or √WAPi10 (P=.510 and .906, respectively). There was no difference in variances for LA, WT, and WA% between pre- and post-bronchodilation (P ranging from .120 to .913).

CT is able to measure bronchodilation in COPD patients reflected by increased LA and decreased WA%, but bronchodilation does not reduce measurements variability. √WAPi10 is insensitive to intraobserver measurements errors or bronchodilation status.

In COPD patients, bronchodilation can be measured by CT but is not an appropriate mean to reduce the number of airways to be measured. √WAPi10 should be preferred to WA% as index of airway dimensions

Hackx, M, Gyssels, E, De Meulder, I, Bruyneel, M, Van Muylem, A, Alard, S, Ninane, V, Gevenois, P, Airways Dimensions and Variability at CT in COPD Patients: Effect of Bronchodilation.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11006079.html