title: Frequency and significance of physiological versus pathological uptake of 68Ga-DOTATATE in the pancreas: validation with morphological imaging.
abstract: OBJECTIVE
  The objective of this study was to assess the relevance of physiological (68)Ga-DOTATATE PET/CT findings in the pancreas guided by morphological imaging (MI) in comparison with pathological tumour uptake in patients with neuroendocrine tumours (NETs).
  
  
  METHODS
  A total of 138 patients with pancreatic NET (pNET; n=38) or non-pNET (n=100) underwent (68)Ga-DOTATATE PET/CT. Pancreatic regions with intensity higher than background were localized with anatomical reference support [head/uncinate process (HUP); body/tail (BT)] and classified as tumour, suspicious or physiological. Maximum standardized uptake value (SUV(max)) was assessed in all regions. PET/CT findings were compared with MI results.
  
  
  RESULTS
  Physiological uptake was seen in 10/38 pNETs (SUV(max) range, mean±SD and median in HUP and BT: 2.4-12.7, 5.9±3.2 and 4.6; 3.8-6.6, 6.6±2.5 and 5.6, respectively). A total of 18/38 showed high uptake (SUV(max) range, mean±SD and median in HUP and BT: 6.9-50, 26.9±13.5 and 27; 10-151, 32.2±36 and 19.4, respectively) with abnormal MI results. Among 10/38 patients we observed a total of n=15 discordant findings between PET/CT and MI: two lesions detected by MI did not correspond to any pathologial uptake on PET/CT, five suspicious uptake in the HUP did not correspond to any abnormal finding on MI, one HUP suspicious uptake correspondend to a lymphadenopaty on MI and seven suspicious BT uptake correspondend to calcification (1/6), cystic lesions (3/6), lesion different form the one detected by PET/CT (1/6) or negative findings (2/6) on MI. Among the 100 patients with non-pNETs, 97 showed homogeneous uptake and three had suspicious pancreatic uptake without concordant findings on MI.
  
  
  CONCLUSIONS
  Physiological pancreatic uptake of (68)Ga-DOTATATE showed low SUV(max), whereas tumours showed higher SUV(max); this is in agreement with previously published data. Equivocal findings showed SUV(max) in the grey area between physiological and pathological ranges, and for these lesions MI and histological confirmation are required for final diagnosis.
authors.affiliation: Departments of aSurgery and Cancer bNuclear Medicine cDivision of Experimental Medicine, Imperial College, Hammersmith Hospital, London, UK.
authors.forename: Paola
authors.initials: P
authors.lastname: Mapelli
authors.forename: Henry H
authors.initials: HH
authors.lastname: Tam
authors.forename: Rohini
authors.initials: R
authors.lastname: Sharma
authors.forename: Eric O
authors.initials: EO
authors.lastname: Aboagye
authors.forename: Adil
authors.initials: A
authors.lastname: Al-Nahhas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001692:Biological Transport; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D009942:Organometallic Compounds / Q000378:metabolism*; D010179:Pancreas / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D049268:Positron-Emission Tomography; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D009942:Organometallic Compounds; C513399:gallium Ga 68 dotatate