title: Imaging features of small (≤ 3 cm) pancreatic solid tumors on gadoxetic-acid-enhanced MR imaging and diffusion-weighted imaging: an initial experience.
abstract: OBJECTIVE
  The objective was to determine imaging features that distinguish small (≤3cm) solid pancreatic adenocarcinoma, neuroendocrine tumor (NET) and solid pseudopapillary tumor (SPT) on gadoxetic-acid-enhanced magnetic resonance imaging (MRI) and diffusion-weighed imaging (DWI).
  
  
  METHODS
  Twenty-four adenocarcinomas, 10 NETs and 8 SPTs were retrospectively included. Two radiologists analyzed morphologic features, signal intensity of the tumors on MR images including DWI (b=800) and dynamic enhancement pattern with consensus. Tumor-to-parenchyma ratio and tumor apparent diffusion coefficients (ADCs) were quantitatively assessed.
  
  
  RESULTS
  All adenocarcinomas had an ill-defined margin and irregular shape, and more frequently had pancreatic duct dilatation compared with other tumors (P<.05). All SPTs and all but one of the adenocarcinomas (95.8%) had no arterial enhancement with progressively increased enhancement, whereas seven NETs (70%) had arterial enhancement with progressively decreased enhancement (P<.01). The mean value of tumor-to-parenchyma ratio on arterial and portal phases was significantly higher for NETs, and the mean value of tumor ADCs was significantly lower for SPTs than for other tumors (P<.05).
  
  
  CONCLUSIONS
  Gadoxetic-acid-enhanced MRI may aid in differentiation between small adenocarcinomas, NETs and SPTs based on morphologic features with dynamic enhancement pattern in adenocarcinomas, dynamic enhancement pattern with tumor-to-parenchyma ration on arterial and portal phases in NETs, and dynamic enhancement pattern with lower ADC value in SPTs.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-Dong, Seoul 135-710, South Korea.
authors.forename: Kyung Mi
authors.initials: KM
authors.lastname: Jang
authors.forename: Seong Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Young Kon
authors.initials: YK
authors.lastname: Kim
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Park
authors.forename: Mi Hee
authors.initials: MH
authors.lastname: Lee
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Hwang
authors.forename: Hyunchul
authors.initials: H
authors.lastname: Rhim
mesh_terms: D018267:Carcinoma, Acinar Cell / Q000473:pathology*; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000473:pathology*; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA