This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. 3rd year medical student - doing his research rotation with mentor, Dr. Bastiaan Driehuys Research in asthmatics and small animal asthma models has indicated that airway constriction leads to regional differences in lung ventilation, which can manifest as ventilation defects. Though the defects are not uniformly distributed throughout the lung, current in vivo methods for assessment of lung function only allow for assessment of global changes. Therefore, these techniques are unable to characterize changes in regions of the lung that are most affected by the disease process.