CRH and adenoma: CRH stimulation may lead to increased 18F-FDG uptake and an increased rate of detection of corticotropinomas in CD. These results also suggest that some MRI-invisible adenomas may be detectable by CRH-stimulated 18F-FDG–PET imaging.These findings invite further prospective evaluation; if validated, CRH-stimulated PET imaging could complement MRI to improve the presurgical visualization of ACTH-secreting microadenomas.