Harvey Owen Coxson PhD, Presenter: Nothing to Disclose

Claudine Storness-Bliss BS, Abstract Co-Author: Nothing to Disclose

Pim A de Jong, Abstract Co-Author: Nothing to Disclose

John Robert Mayo MD, Abstract Co-Author: Nothing to Disclose

Robert D Levy, Abstract Co-Author: Nothing to Disclose

To quantify gas trapping in the presence of post-lung transplant bronchiolitis obliterans using computed tomography (CT) scans.

Post-transplant inspiratory and expiratory high resolution CT scans were collected from 48 lung transplant recipients. Patients were divided into categories of airflow obstruction severity using the International Society of Heart and Lung Transplantation bronchiolitis obliterans syndrome (BOS) stages: BOS 0 (no airflow obstruction on spirometry, N=26), BOS 1 (mild obstruction, N=15) and BOS 2-3 (moderate-severe obstruction, N=7). The CT lung inflation (ml gas/g tissue) was calculated for the transplanted lung using x-ray attenuation values for both inspiratory and expiratory CT scans and plotted as cumulative distribution curves. The predicted maximal lung expansion (MLE, in ml gas/g tissue) for each individual patient was calculated by dividing the recipient’s predicted total lung capacity (ml of gas) by his/her predicted lung weight (g of tissue). To estimate the extent of gas trapping, the proportion of the expiratory CT scan voxels with an inflation value less than the MLE was divided by the proportion of the inspiratory CT voxels with an inflation value less than the MLE. A logistic regression was used to model the association between proportion of lung voxels inflated below MLE on the expiration and inspiration CT scans. This model examines the effect of BOS stage on the difference between the inflation of the lung in expiration and inspiration compared to BOS stage 0.

There was a significant association between the expiration/inspiration ratio and disease stage (p<0.001). In BOS stage 0, the expiration/inspiration ratio of CT inflation below MLE was 4.19 (95% confidence interval (CI): 4.19, 4.20). As airflow limitation worsened, the ratio was 3.69 (CI: 3.68, 3.70) in BOS 1 and 3.49 (CI: 3.47, 3.50) in BOS 2-3.

This quantitative technique can objectively measure significant differences in gas trapping associated with lung allograph dysfunction and holds promise for early detection of bronchiolitis obliterans.

H.O.C.: A percentage of Harvey Coxson’s salary between 2003 and 2006 (15,000 US $/year) derives from contract funds provided to a colleague Peter D Pare by GSK for the development of validated methods to measure emphysema and airway disease using computed tomography

Coxson, H, Storness-Bliss, C, de Jong, P, Mayo, J, Levy, R, The Detection of Bronchiolitis Obliterans Following Lung Transplantation Using Quantitative Computed Tomography.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4419045.html