title: Isoattenuating insulinomas at biphasic contrast-enhanced CT: frequency, clinicopathologic features and perfusion characteristics.
abstract: OBJECTIVE
  We aimed to determine the frequency of isoattenuating insulinomas, to investigate their clinicopathological features and to assess their regional pancreatic perfusion characteristics.
  
  
  METHODS
  Institutional review board approval was obtained, and patient informed consent was waived. From July 2010 to June 2014, 170 patients (66 male, 104 female) with endogenous hyperinsulinemic hypoglycemia underwent biphasic contrast-enhanced CT before surgery, and 129 of those patients also received preoperative whole-pancreas CT perfusion. A total of 181 tumours were proved histopathologically after surgery. Enhancement pattern and regional pancreatic perfusion characteristics were analyzed. Clinical features, tumour size and pathological grading were investigated.
  
  
  RESULTS
  The frequency of isoattenuating tumours was 24.9 %. Tumour size and WHO grading was not significantly different between isoattenuating and hyperattenuating tumours. Tumour-free regions had identical blood flow (BF) regardless of their location (p = 0.35). Isoattenuating tumour-harbouring regions had lower BF compared with hyperattenuating tumour-harbouring regions; both showed higher BF compared with tumour-free neighbourhood regions (all p < 0.01). For patients with isoattenuating tumours, the overall hospital stay was longer (p < 0.01).
  
  
  CONCLUSIONS
  A substantial subset of insulinomas were isoattenuating on biphasic CT. CT perfusion showed higher BF in tumour-harbouring regions compared to tumour-free regions, providing a clue for tumour regionalization.
  
  
  CONCLUSIONS
  • About a quarter of all insulinomas were isoattenuating on biphasic contrast-enhanced CT. • CT perfusion finds tumour-harbouring regions have higher blood-flow compared to tumour-free regions. • CT perfusion provides important information for tumour regionalization, for isoattenuating tumours.
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China. bjdanna95@hotmail.com.
authors.forename: Hua-Dan
authors.initials: HD
authors.lastname: Xue
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China.
authors.forename: Yong-Lan
authors.initials: YL
authors.lastname: He
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China.
authors.forename: Zheng-Yu
authors.initials: ZY
authors.lastname: Jin
authors.affiliation: Department of General Surgery, Peking Union Medical College Hospital, Shuaifuyuan No.1, Dongcheng District, Beijing, China.
authors.forename: Yu-Pei
authors.initials: YP
authors.lastname: Zhao
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D006801:Humans; D007340:Insulinoma / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods; D060787:Neoplasm Grading; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging; D010190:Pancreatic Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D010477:Perfusion; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media
keywords: Insulinoma; Multidetector computed tomography; Multiple endocrine neoplasia; Perfusion; Sporadic
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