title: [11C]metomidate positron emission tomography of adrenocortical tumors in correlation with histopathological findings.
abstract: BACKGROUND
  Adrenal incidentalomas are common findings necessitating extensive laboratory work-up and repetitive radiological examinations. Positron emission tomography (PET) using (11)C-labeled metomidate (MTO) has previously been described as a tool for specific adrenocortical imaging.
  
  
  OBJECTIVE
  We evaluated 212 MTO-PET examinations in 173 patients to identify its role in the management of adrenal tumors.
  
  
  METHODS
  Seventy-five histopathological examinations from 73 patients were retrospectively analyzed.
  
  
  METHODS
  All examinations were performed at a referral center.
  
  
  METHODS
  Patients who were operated or biopsied due to adrenal tumors had histopathological diagnoses of adrenocortical adenoma (n = 26), adrenocortical cancer (ACC; n = 13), adrenocortical hyperplasia (n = 8), pheochromocytoma (n = 6), metastasis (n = 3), and tumors of nonadrenal origin (n = 19).
  
  
  METHODS
  The main outcome measures were statistical analyses and findings while scrutinizing images. The hypothesis that MTO-PET is of value in the management of adrenal tumors, especially incidentaloma, was stated before data collection.
  
  
  RESULTS
  Sensitivity was 0.89 and specificity was 0.96 for MTO-PET in proving adrenocortical origin of the lesions. Pheochromocytomas, metastases to the adrenal gland, and nonadrenal masses were all MTO negative. PET measurements using standardized uptake values (SUV) in pathological adrenocortical tissue could differentiate lesions larger than 1-1.5 cm from normal adrenocortical tissue. SUV was higher in aldosterone-hypersecreting adenomas, and the SUV ratio between the tumor and the contralateral gland was significantly higher in all hormonally hypersecreting adenomas as well as in ACC.
  
  
  CONCLUSIONS
  MTO-PET is a specific and sensitive method for diagnosing adrenocortical tumors. MTO-PET is useful in the imaging work-up of adrenal incidentalomas and may be beneficial for the examination of patients with primary aldosteronism or ACC.
authors.affiliation: Department of Surgery, University Hospital, SE-751 85 Uppsala, Sweden.
authors.forename: Joakim
authors.initials: J
authors.lastname: Hennings
authors.forename: Orjan
authors.initials: O
authors.lastname: Lindhe
authors.forename: Mats
authors.initials: M
authors.lastname: Bergström
authors.forename: Bengt
authors.initials: B
authors.lastname: Långström
authors.forename: Anders
authors.initials: A
authors.lastname: Sundin
authors.forename: Per
authors.initials: P
authors.lastname: Hellman
mesh_terms: D000306:Adrenal Cortex Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D000368:Aged; D000970:Antineoplastic Agents; D003627:Data Interpretation, Statistical; D004989:Ethics; D005045:Etomidate / Q000031:analogs & derivatives*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals
chemical_list: D000970:Antineoplastic Agents; D019275:Radiopharmaceuticals; C084586:metomidate; D005045:Etomidate