title: Detection of neuroendocrine tumours in the small intestines using contrast-enhanced multiphase Ga-68 DOTATOC PET/CT: the potential role of arterial hyperperfusion.
abstract: BACKGROUND
  Interpretation of small intestinal neuroendocrine tumours (NETs) by Ga-68 DOTATOC PET/CT can be difficult. The potential benefit of arterial hyperperfusion for the detection of NETs was evaluated.
  
  
  METHODS
  Between 2006 and 2009, 320 consecutive Ga-68 DOTATOC PET/CT examinations, performed for NETs, revealed 40 lesions suggesting intestinal NETs in 25 patients. Two groups of lesions were distinguished: epigastric lesions evaluable in the arterial and venous CT scan (Group 1) and hypogastrial lesions evaluable in the venous CT scan only (Group 2). Lesions were jointly rated by two radiologists and a nuclear medicine physician. Maximum standard uptake values (SUVmax) of lesions and background were assessed. The reference standard was histology (available for 28 lesions) or follow-up (for a mean of 22.9 months).
  
  
  RESULTS
  PET detected all suspicious lesions but was false positive in 3 lesions. In Group 1 the arterial scan performed significantly better than the venous scan (p = 0.008). Diagnostic performance was better in Group 1 than in Group 2 (p < 0.001). SUVmax of true positive lesions were significantly higher than background SUVmax (p < 0.001) and SUVmax of false positive lesions (p = 0.005).
  
  
  CONCLUSIONS
  The arterial phase of multiphase Ga-68 DOTATOC PET/CT might improve the localization of intestinal NETs and, thereby, improve the overall diagnostic accuracy of this modality in the assessment of intestinal NETs by adding information about lesion perfusion not available when only venous CT is performed.
authors.affiliation: Department of Nuclear Medicine, Charité, Berlin, Germany.
authors.forename: Nils F
authors.initials: NF
authors.lastname: Schreiter
authors.affiliation: Department of Radiology, Charité, Berlin, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Maurer
authors.affiliation: Department of Gastroenterology, Charité, Berlin, Germany.
authors.forename: Ulrich-Frank
authors.initials: UF
authors.lastname: Pape
authors.affiliation: Department of Radiology, Charité, Berlin, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Hamm
authors.affiliation: Department of Nuclear Medicine, Charité, Berlin, Germany.
authors.forename: Winfried
authors.initials: W
authors.lastname: Brenner
authors.affiliation: Department of Radiology, Charité, Berlin, Germany.
authors.forename: Vera
authors.initials: V
authors.lastname: Froeling
keywords: Ga-68 DOTATOC PET/CT; arterial phase CT; neuroendocrine tumors; small intestine