title: Insulinoma Detection With MDCT: Is There a Role for Whole-Pancreas Perfusion?
abstract: OBJECTIVE
  The purpose of this study is to investigate the role of whole-pancreas perfusion in detecting insulinomas with the use of MDCT.
  
  
  METHODS
  From January 2011 to December 2011, a total of 70 consecutive patients (33 men and 37 women; mean age, 46 years; range, 17-73 years) who underwent biphasic contrast-enhanced CT and whole-pancreas CT perfusion for suspected insulinomas were identified retrospectively. Patients were monitored for at least 3 years. Two radiologists who were blinded to the clinical and surgical data independently evaluated the images, first assessing only the biphasic contrast-enhanced CT images to detect tumor and assess diagnostic confidence on a 5-point scale. Next, perfusion parametric maps were evaluated and pancreatic perfusion parameters measured, and the presence of tumor was reidentified using a combination of the biphasic CT and perfusion image sets. A ROC curve was generated to compare the diagnostic accuracy of the two image sets.
  
  
  RESULTS
  The mean blood flow (BF) values of both the insulinomas and the insulinoma-harboring regions were statistically significantly higher (p < 0.01, for both) than the BF value of tumor-free pancreatic parenchyma. For the detection of insulinoma, biphasic CT had a sensitivity of 88.1%, a specificity of 85.7%, a positive predictive value of 91.1%, and a negative predictive value of 81.4%, whereas combined biphasic CT and perfusion had a sensitivity of 94.6%, a specificity of 94.7%, a positive predictive value of 96.7%, and a negative predictive value of 91.5%. The mean area under the ROC curve increased from 0.939 with biphasic CT to 0.999 with the addition of perfusion. Nine of 46 tumors (19.6%) for which findings were negative (n = 2) or indeterminate (n = 7) on biphasic CT were correctly diagnosed with the addition of perfusion.
  
  
  CONCLUSIONS
  The addition of pancreatic perfusion to biphasic contrast-enhanced CT may improve the detection of insulinomas.
authors.affiliation: 1 Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China, 100730.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhu
authors.affiliation: 1 Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China, 100730.
authors.forename: Huadan
authors.initials: H
authors.lastname: Xue
authors.affiliation: 1 Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China, 100730.
authors.forename: Hao
authors.initials: H
authors.lastname: Sun
authors.affiliation: 1 Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China, 100730.
authors.forename: Xuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: 2 Department of General Surgery, Peking Union Medical College Hospital, Beijing, China.
authors.forename: Wenming
authors.initials: W
authors.lastname: Wu
authors.affiliation: 1 Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China, 100730.
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Jin
authors.affiliation: 2 Department of General Surgery, Peking Union Medical College Hospital, Beijing, China.
authors.forename: Yupei
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000072226:Computed Tomography Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007340:Insulinoma / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging*; D010190:Pancreatic Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: MDCT; insulinoma; pancreatic imaging; perfusion