Characterization of Subjects with Severe Asthma- SARP 2

The SARP II protocol will also incorporate the use of inspiratory and expiratory CT imaging of the lungs to enable SARP researchers to non-invasively estimate airway compliance in both normal subjects and subjects with asthma. For subjects that meet the ancillary imaging protocol criteria, the images will be sent to the University of Iowa where airway wall measurements will be made and an additional three-dimensional (3D) multi-detector CT (MDCT) computer-based image will be created. This computer generated airway tree information will be used to direct where endobronchial biopsies will be obtained for the optimal sampling of a remodeled airway. The evaluation of wall thickness, lumen area and air trapping in SARP II has the potential to be extremely useful for assessing whether the histologic changes of airway remodeling in the segmental airways are related to overall airway thickness, and whether segmental airway wall thickness is of functional importance in distinguishing well-controlled from severe asthma. Furthermore, if the relationship of airway wall thickness to airway wall histology and asthma severity is confirmed, this may represent a new target for therapies aimed at reversing or preventing remodeling.