title: 18F-FDG PET/MRI fusion in characterizing pancreatic tumors: comparison to PET/CT.
abstract: OBJECTIVE
  To demonstrate that positron emission tomography (PET)/magnetic resonance imaging (MRI) fusion was feasible in characterizing pancreatic tumors (PTs), comparing MRI and computed tomography (CT) as mapping images for fusion with PET as well as fused PET/MRI and PET/CT.
  
  
  METHODS
  We retrospectively reviewed 47 sets of (18)F-fluorodeoxyglucose ((18)F -FDG) PET/CT and MRI examinations to evaluate suspected or known pancreatic cancer. To assess the ability of mapping images for fusion with PET, CT (of PET/CT), T1- and T2-weighted (w) MR images (all non-contrast) were graded regarding the visibility of PT (5-point confidence scale). Fused PET/CT, PET/T1-w or T2-w MR images of the upper abdomen were evaluated to determine whether mapping images provided additional diagnostic information to PET alone (3-point scale). The overall quality of PET/CT or PET/MRI sets in diagnosis was also assessed (3-point scale). These PET/MRI-related scores were compared to PET/CT-related scores and the accuracy in characterizing PTs was compared.
  
  
  RESULTS
  Forty-three PTs were visualized on CT or MRI, including 30 with abnormal FDG uptake and 13 without. The confidence score for the visibility of PT was significantly higher on T1-w MRI than CT. The scores for additional diagnostic information to PET and overall quality of each image set in diagnosis were significantly higher on the PET/T1-w MRI set than the PET/CT set. The diagnostic accuracy was higher on PET/T1-w or PET/T2-w MRI (93.0 and 90.7%, respectively) than PET/CT (88.4%), but statistical significance was not obtained.
  
  
  CONCLUSIONS
  PET/MRI fusion, especially PET with T1-w MRI, was demonstrated to be superior to PET/CT in characterizing PTs, offering better mapping and fusion image quality.
authors.affiliation: Department of Nuclear Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, Japan. dy8m-ttm@asahi-net.or.jp
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Tatsumi
authors.forename: Kayako
authors.initials: K
authors.lastname: Isohashi
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Onishi
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hori
authors.forename: Tonsok
authors.initials: T
authors.lastname: Kim
authors.forename: Ichiro
authors.initials: I
authors.lastname: Higuchi
authors.forename: Atsuo
authors.initials: A
authors.lastname: Inoue
authors.forename: Eku
authors.initials: E
authors.lastname: Shimosegawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takeda
authors.forename: Jun
authors.initials: J
authors.lastname: Hatazawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography / Q000379:methods; D011859:Radiography; D016896:Treatment Outcome
chemical_list: D019788:Fluorodeoxyglucose F18