Cystic Fibrosis (CF) is an autosomal recessive genetic disease, caused by mutations of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) that impairs ion transport at epithelial surfaces. This results in the accumulation of dehydrated secretions in the airways and chronic infection and inflammation in the lungs, leading to significant morbidity and mortality. The investigators understanding of CF pathogenesis has increased substantially and many new targeted therapies are being developed to treat this disease, however, the measurements of clinical efficacy used to evaluate these therapies require long trials to demonstrate an effect. New translational techniques are needed to assess changes in the most basic aspects of the disease and allow for the rapid screening of disease-altering therapies. The investigators have recently developed a novel aerosol-based imaging technique to measure liquid absorption in the airways - a central pathophysiological process related to CFTR dysfunction. The investigators propose that airway liquid hyper-absorption is a key link between cellular defects in ion and fluid transport and progressive airway dysfunction in CF. Thus The investigators technique may provide a measure of disease severity and rapid indication of therapeutic correction in advance of currently available outcome measures.