FDG-PET Imaging in Young Cystic Fibrosis Patients

Our recent study in CF adults, supplemented by recent pre-clinical and clinical studies by
our group suggests that labeled fluorodeoxyglocose-based positron emission tomography
(FDG-PET) imaging may be a valuable quantitative biomarker of lung inflammation. The proposed
study would validate our earlier findings, but in a younger patient population. The
implications of such a test could be highly significant for both the testing of promising new
anti-inflammatory agents and for patient management decisions. To capitalize on this exciting
opportunity, the critical next step is to show that we can identify a cohort of young CF
patients with both stable lung function and normal (or near normal) FDG-PET imaging studies.
Similar patients, then, would become the subjects for a future prospective cohort study to
determine if FDG-PET imaging can in fact serve as a predictor of future changes in lung
function.

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