title: Role of (68)Ga somatostatin receptor PET/CT in the detection of endogenous hyperinsulinaemic focus: an explorative study.
abstract: OBJECTIVE
  To explore the role of (68)Ga-DOTATATE/DOTATOC PET/CT (SR PET/CT) in patients with suspicion of or histopathologically proven pancreatogenic hyperinsulinaemic hypoglycaemia.
  
  
  METHODS
  We included 13 patients with histopathologically proven or a high clinical suspicion of pancreatogenic hyperinsulinaemia. All the patients underwent a SR PET/CT scan. The results were correlated with histopathological findings. Normalization of blood glucose levels after resection of the pancreatic lesion, as well as a cytological and/or pathological diagnosis of insulinoma, was considered the diagnostic gold standard for insulinoma. The diagnosis of nesidioblastosis was based on exclusion of an insulinoma and conclusive pathological examination of a segment of the pancreas. Malignant insulinoma was defined as the presence of locoregional or distant metastases.
  
  
  RESULTS
  Based on histopathology, 13 patients were found to have pancreatic hyperinsulinaemia: two patients had malignant insulinoma, eight had nonmetastasized insulinoma, and three had nesidioblastosis. SR PET was positive in 11 of the 13 patients (84.6 %) with a final diagnosis of endogenous pancreatic hypoglycaemia. Histopathological staining confirmed 16 foci of hyperinsulinism (insulin positivity). SR PET detected 14 of the 16 lesions, resulting in a sensitivity of 87 %. One intrapancreatic spleen was falsely diagnosed as insulinoma focus on SR PET, resulting in positive predictive value of 93.3 %. Immunohistochemical staining of somatostatin receptor (SSR) subtype 2a was available in ten specimens: two nesidioblastosis, and seven benign and one malignant insulinoma. Eight out of the ten specimens (80 %) stained strongly to moderately positive. Seven of the eight SSR2a-positive lesions were picked up on SR PET. Based on the results of SR PET/CT, nine patients achieved complete remission of the hypoglycaemic events during follow-up.
  
  
  CONCLUSIONS
  This explorative study suggests that SR PET in combination with CT may play a significant role in the detection and management of patients with pancreatogenic hyperinsulinaemic hypoglycaemia. A large proportion of insulinomas express SSR2a, and a larger study is needed to fully assess the diagnostic accuracy of SR PET in patients with insulinoma and nesidioblastosis compared with current localizing studies used in clinical practice.
authors.affiliation: Department of Nuclear Medicine, Charité Universitätsmedizin Berlin, Berlin, Germany. vikas.prasad@charite.de.
authors.forename: Vikas
authors.initials: V
authors.lastname: Prasad
authors.affiliation: Department of Nuclear Medicine, Hospital Clínico Universitario Valladolid, Valladolid, Spain.
authors.forename: Aurora
authors.initials: A
authors.lastname: Sainz-Esteban
authors.affiliation: Institute of Pathology, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Ruza
authors.initials: R
authors.lastname: Arsenic
authors.affiliation: Interdisziplinären Stoffwechsel-Centrum, Department of Hepatology and Gastroenterology, Charité Universitätsmedizin Berlin, Campus Virchow Klinikum, Berlin, Germany.
authors.forename: Ursula
authors.initials: U
authors.lastname: Plöckinger
authors.affiliation: Department of Radiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Timm
authors.initials: T
authors.lastname: Denecke
authors.affiliation: Department of Hepatology and Gastroenterology, Charité Universitätsmedizin Berlin, Campus Virchow Klinikum, Berlin, Germany.
authors.forename: Ulrich-Frank
authors.initials: UF
authors.lastname: Pape
authors.affiliation: Department of General, Visceral and Transplant Surgery, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Pascher
authors.affiliation: Institute for Experimental Paediatric Endocrinology, Charité-Universitätsmedizin Berlin, Campus Virchow Klinikum, Berlin, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Kühnen
authors.affiliation: Department of Hepatology and Gastroenterology, Charité Universitätsmedizin Berlin, Campus Virchow Klinikum, Berlin, Germany.
authors.forename: Marianne
authors.initials: M
authors.lastname: Pavel
authors.affiliation: Institute for Experimental Paediatric Endocrinology, Charité-Universitätsmedizin Berlin, Campus Virchow Klinikum, Berlin, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Blankenstein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005710:Gallium Radioisotopes; D005786:Gene Expression Regulation; D006801:Humans; D006946:Hyperinsulinism / Q000150:complications / Q000000981:diagnostic imaging* / Q000378:metabolism; D007003:Hypoglycemia / Q000150:complications; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000378:metabolism; D000072078:Positron Emission Tomography Computed Tomography; D017481:Receptors, Somatostatin / Q000378:metabolism; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D005710:Gallium Radioisotopes; D017481:Receptors, Somatostatin; C574734:SSTR2 protein, human
keywords: 68Ga-DOTATATE; 68Ga-DOTATOC; Insulinoma; Nesidioblastosis; PET/CT; Somatostatin receptor