The primary objective of this study is to determine the effect of CRH stimulation on (18)F-FDG uptake in high-resolution PET-imaging for CD. To assess and compare (18)F-FDG uptake without and with CRH stimulation, we will compare (18)F-FDG standardized uptake values (SUVs) in the region of interest (pituitary gland and pituitary adenoma). Secondary objectives include determining if CRH stimulation enhances detection of ACTH-adenomas as demonstrated on (18)F-FDG high-resolution PET-imaging and assessing the accuracy and sensitivity of (18)F-FDG high-resolution PET-imaging detection of ACTH-adenomas compared to MR-imaging. Measures to assess for these secondary objectives include comparing (18)F-FDG high-resolution PET-imaging (with and without CRH stimulation) detection to (1) MR-imaging detection of adenomas, (2) IPSS results, and (3) actual tumor location confirmed by histological findings to location predicted by PET- and MR-imaging within patients.