title: Targeted Molecular Imaging in Adrenal Disease-An Emerging Role for Metomidate PET-CT.
abstract: Adrenal lesions present a significant diagnostic burden for both radiologists and endocrinologists, especially with the increasing number of adrenal 'incidentalomas' detected on modern computed tomography (CT) or magnetic resonance imaging (MRI). A key objective is the reliable distinction of benign disease from either primary adrenal malignancy (e.g., adrenocortical carcinoma or malignant forms of pheochromocytoma/paraganglioma (PPGL)) or metastases (e.g., bronchial, renal). Benign lesions may still be associated with adverse sequelae through autonomous hormone hypersecretion (e.g., primary aldosteronism, Cushing's syndrome, phaeochromocytoma). Here, identifying a causative lesion, or lateralising the disease to a single adrenal gland, is key to effective management, as unilateral adrenalectomy may offer the potential for curing conditions that are typically associated with significant excess morbidity and mortality. This review considers the evolving role of positron emission tomography (PET) imaging in addressing the limitations of traditional cross-sectional imaging and adjunctive techniques, such as venous sampling, in the management of adrenal disorders. We review the development of targeted molecular imaging to the adrenocortical enzymes CYP11B1 and CYP11B2 with different radiolabeled metomidate compounds. Particular consideration is given to iodo-metomidate PET tracers for the diagnosis and management of adrenocortical carcinoma, and the increasingly recognized utility of11C-metomidate PET-CT in primary aldosteronism.
authors.affiliation: Department of Radiology, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK. im391@cam.ac.uk.
authors.forename: Iosif A
authors.initials: IA
authors.lastname: Mendichovszky
authors.affiliation: Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK. asp22@medschl.cam.ac.uk.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Powlson
authors.affiliation: Department of Radiology, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK. rm617@cam.ac.uk.
authors.forename: Roido
authors.initials: R
authors.lastname: Manavaki
authors.affiliation: Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 1TN, UK. fia20@medschl.cam.ac.uk.
authors.forename: Franklin I
authors.initials: FI
authors.lastname: Aigbirhio
authors.affiliation: Department of Radiology, University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK. heok.cheow@addenbrookes.nhs.uk.
authors.forename: Heok
authors.initials: H
authors.lastname: Cheow
authors.affiliation: Department of Nuclear Medicine, Cambridge University Hospitals, Cambridge CB2 0QQ, UK. john.buscombe@addenbrookes.nhs.uk.
authors.forename: John R
authors.initials: JR
authors.lastname: Buscombe
authors.affiliation: Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK. mg299@medschl.cam.ac.uk.
authors.forename: Mark
authors.initials: M
authors.lastname: Gurnell
authors.affiliation: Department of Radiology, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK. fjg28@medschl.cam.ac.uk.
authors.forename: Fiona J
authors.initials: FJ
authors.lastname: Gilbert
keywords: adrenal; adrenocortical carcinoma; metomidate; nuclear medicine; primary aldosteronism