title: Pancreatic neuroendocrine neoplasms: Magnetic resonance imaging features according to grade and stage.
abstract: OBJECTIVE
  To describe magnetic resonance (MR) imaging features of pancreatic neuroendocrine neoplasms (PanNENs) according to their grade and tumor-nodes-metastases stage by comparing them to histopathology and to determine the accuracy of MR imaging features in predicting their biological behavior.
  
  
  METHODS
  This study was approved by our institutional review board; requirement for informed patient consent was waived due to the retrospective nature of the study. Preoperative MR examinations of 55 PanNEN patients (29 men, 26 women; mean age of 57.6 years, range 21-83 years) performed between June 2013 and December 2015 were reviewed. Qualitative and quantitative features were compared between tumor grades and stages determined by histopathological analysis.
  
  
  RESULTS
  Ill defined margins were more common in G2-3 and stage III-IV PanNENs than in G1 and low-stage tumors (P< 0.001); this feature had high specificity in the identification of G2-3 and stage III-IV tumors (90.3% and 96%, 95%CI: 73.1-97.5 and 77.7-99.8). The mean apparent diffusion coefficient value was significantly lower in G2-3 and stage III-IV lesions compared to well differentiated and low-stage tumors (1.09 × 10-3mm2/svs1.45 × 10-3mm2/s and 1.10 × 10-3mm2/svs1.53 × 10-3mm2/s,P= 0.003 and 0.001). Receiving operator characteristic analysis determined optimal cut-offs of 1.21 and 1.28 × 10-3mm2/s for the identification of G2-3 and stage III-IV tumors, with sensitivity and specificity values of 70.8/80.7% and 64.5/64% (95%CI: 48.7-86.6/60-92.7 and 45.4-80.2/42.6-81.3).
  
  
  CONCLUSIONS
  MR features of PanNENs vary according to their grade of differentiation and their stage at diagnosis and could predict the biological behavior of these tumors.
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: De Robertis
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Cingarlini
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Tinazzi Martini
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Ortolani
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Butturini
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Landoni
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Regi
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Girelli
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Capelli
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Gobbo
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Tortora
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Aldo
authors.initials: A
authors.lastname: Scarpa
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Pederzoli
authors.affiliation: Riccardo De Robertis, Department of Radiology, Casa di Cura Pederzoli, 37019 Peschiera del Garda, Italy.
authors.forename: Mirko
authors.initials: M
authors.lastname: D'Onofrio
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008536:Meglumine / Q000008:administration & dosage / Q000031:analogs & derivatives; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging* / Q000473:pathology*; D009942:Organometallic Compounds / Q000008:administration & dosage; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D011300:Preoperative Care / Q000379:methods; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine
keywords: Diffusion-weighted imaging; European Neuroendocrine Tumor Society staging system; Magnetic resonance imaging; Pancreatic neuroendocrine tumor; World Health Organization classification 2010