[¹¹C]Methionine PET uptake kinetics in corticotroph pituitary neuroendocrine tumors

Abstract [11C]Methionine ([11C]MET) PET provides high sensitivity to localize corticotroph pituitary neuroendocrine tumors (PitNETs) in de novo Cushing’s disease but remains inconclusive in up to 20% of cases. Current PET protocols rely on late acquisitions (20–40 min post-injection). Since other endocrine tumors present earlier peak tracer uptake, corticotroph PitNETs might also exhibit early differential amino acid uptake, compared to the normal pituitary gland. This exploratory study based on data derived from a previously registered prospective multicenter cohort study (ClinicalTrials.gov identifier: NCT03346954) included 15 patients with pathologically confirmed corticotroph PitNETs accurately localized using MRI. Kinetic analysis showed rapid early uptake in PitNETs and normal pituitary gland, followed by a significant decline over time, with consistently higher uptake in PitNETs (p