FDG-PET Imaging in Young Cystic Fibrosis Patients

Inclusion Criteria: * Confirmed diagnosis of cystic fibrosis * Age 12 to 21 years old, of either gender, any race or ethnicity * Stable recent pulmonary status (defined as no new pulmonary symptoms, new antibiotic use, or hospitalization for pulmonary symptoms for at least 1 month). * We will permit patients treated with the macrolide antibiotic, azithromycin, to participate in this study. Azithromycin has recently become a virtual standard of care in CF, based on small but reproducible improvements in pulmonary function over 4 months of treatment with this drug. The mechanism of benefit is uncertain, but an anti-inflammatory effect has been suggested. The high prevalence of use means that a study without azithromycin would likely require a wash-out period, without data about the appropriate duration for such a wash-out, or whether inflammatory markers would reverse during that time. Exclusion Criteria: * Failure to obtain informed consent * Positive pregnancy test or lactation * Currently enrolled in another study involving radioisotopes or an investigational drug * Recent (within 30 days of screening) hospitalization for any reason * New antibiotic use (within 30 days of screening). * Patient incapable of lying still and supine within the PET/computed X-ray tomography (CT) scanner for 90 minutes. * Patient incapable of completing other testing procedures (e.g., PFT, induced sputum) * Patient with serum glucose greater than 150 mg/dl at time of PET imaging study * Patient incapable of fasting for 4 to 6 hrs prior to PET imaging study