title: Dual energy spectral CT imaging of insulinoma-Value in preoperative diagnosis compared with conventional multi-detector CT.
abstract: OBJECTIVE
  The aim of this study was to investigate the value of dual energy spectral CT (DEsCT) imaging in preoperative diagnosis of insulinomas in comparison with conventional multi-detector CT (MDCT).
  
  
  METHODS
  Thirty-five patients were included in this study with 14 underwent the conventional dual-phase CT imaging (from March 2009 to January 2010) and 21 underwent the dual-phase DEsCT imaging (from February 2010 to May 2011). CT images were interpreted prospectively by two radiologists in consensus before operation. All the patients had diagnosis confirmed pathologically. The accuracy of preoperative diagnosis of insulinomas between DEsCT imaging and conventional MDCT, and between different kinds of images of DEsCT was compared.
  
  
  RESULTS
  There were 39 confirmed lesions among the 35 patients (23 and 16 tumors in the spectral CT group and MDCT group, respectively). MDCT detected 11 of 16 tumors. DEsCT imaging detected 20 of 23 tumors separately with the monochromatic image or the iodine density image, and 22 of 23 tumors with the combination of the two kinds of images. The sensitivity for the preoperative diagnosis of insulinoma was 95.7% with the combination of monochromatic and iodine density images in DEsCT imaging, statistically higher than that with the conventional MDCT (68.8%) (p=0.033).
  
  
  CONCLUSIONS
  Dual energy spectral CT imaging has higher sensitivity in preoperative diagnosis of insulinomas compared with conventional MDCT. The combination of monochromatic image and iodine density image can improve the diagnostic sensitivity of insulinomas.
authors.affiliation: Department of Radiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, 197, 2nd Ruijin Road, Shanghai 200025, China. lin xiaozhu rj@hotmail.com
authors.forename: Xiao Zhu
authors.initials: XZ
authors.lastname: Lin
authors.forename: Zhi Yuan
authors.initials: ZY
authors.lastname: Wu
authors.forename: Ran
authors.initials: R
authors.lastname: Tao
authors.forename: Yan
authors.initials: Y
authors.lastname: Guo
authors.forename: Jian Ying
authors.initials: JY
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Ke Min
authors.initials: KM
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007340:Insulinoma / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging*; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult