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International Journal of Biomedical Imaging
Volume 2012 (2012), Article ID 956248, 14 pages
http://dx.doi.org/10.1155/2012/956248
Research Article

Tracking Regional Tissue Volume and Function Change in Lung Using Image Registration

1GE Global Research, Niskayuna, NY 12309, USA
2Department of Electrical and Computer Engineering, The University of Iowa, Iowa City, IA 52242, USA
3Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242, USA
4Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA 23298, USA
5Department of Biomedical Engineering, The University of Iowa, 1402A SC, Iowa City, IA 52242, USA
6Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242, USA

Received 18 June 2012; Accepted 6 September 2012

Academic Editor: Ayman El-Baz

Copyright © 2012 Kunlin Cao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We have previously demonstrated the 24-hour redistribution and reabsorption of bronchoalveolar lavage (BAL) fluid delivered to the lung during a bronchoscopic procedure in normal volunteers. In this work we utilize image-matching procedures to correlate fluid redistribution and reabsorption to changes in regional lung function. Lung CT datasets from six human subjects were used in this study. Each subject was scanned at four time points before and after BAL procedure. Image registration was performed to align images at different time points and different inflation levels. The resulting dense displacement fields were utilized to track tissue volume changes and reveal deformation patterns of local parenchymal tissue quantitatively. The registration accuracy was assessed by measuring landmark matching errors, which were on the order of 1 mm. The results show that quantitative-assessed fluid volume agreed well with bronchoscopist-reported unretrieved BAL volume in the whole lungs (squared linear correlation coefficient was 0.81). The average difference of lung tissue volume at baseline and after 24 hours was around 2%, which indicates that BAL fluid in the lungs was almost absorbed after 24 hours. Regional lung-function changes correlated with the presence of BAL fluid, and regional function returned to baseline as the fluid was reabsorbed.