title: Novel quantitative perfusion analysis with contrast-enhanced harmonic EUS for differentiation of autoimmune pancreatitis from pancreatic carcinoma.
abstract: OBJECTIVE
  Autoimmune pancreatitis (AIP) is often misdiagnosed as pancreatic carcinoma (PC) despite recent advances in imaging tests. The aim of the study was to evaluate whether the quantitative perfusion analysis using software "Time intensity curve" with contrast-enhanced harmonic EUS (CH-EUS) facilitate the differentiation of AIP from PC.
  
  
  METHODS
  Consecutive patients with focal AIP and pancreatic carcinoma who underwent CH-EUS from January 2009 to September 2010 were analyzed. CH-EUS was performed with intravenous administration of an ultrasonographic contrast (Sonazoid) and electronic radial echoendoscope. The graph of time intensity curve (TIC) for pancreatic mass was generated to depict the changes in signal intensity over time within the region of interest (ROI). ROI was placed to cover an area with a pancreatic mass lesion. Based on the analysis of TIC, base intensity before injection (BI), peak intensity (PI), time to peak, and maximum intensity gain (MIG: PI-BI) were calculated.
  
  
  RESULTS
  Eight patients with focal AIP and twenty-two patients with PC were evaluated by TIC. PI and MIG of mass lesion of AIP were significantly higher than that of PC (21.4 dB vs. 9.6 dB, 17.5 vs. 6.6). Receiver operating characteristics analysis yielded an optimal MIG cutoff value of 12.5 with high sensitivity and specificity.
  
  
  CONCLUSIONS
  Pancreatic mass lesions of AIP and PC exhibited markedly different patterns with the TIC. This novel diagnostic modality using TIC generated by CH-EUS might offer an opportunity to improve accuracy in the differential diagnosis between pancreatic mass lesion of AIP and PC.
authors.affiliation: Department of Endoscopy, The Jikei University School of Medicine, Tokyo, Japan. himazu21@aol.com
authors.forename: Hiroo
authors.initials: H
authors.lastname: Imazu
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kanazawa
authors.forename: Naoki
authors.initials: N
authors.lastname: Mori
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ikeda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kakutani
authors.forename: Kazuki
authors.initials: K
authors.lastname: Sumiyama
authors.forename: Shoryoku
authors.initials: S
authors.lastname: Hino
authors.forename: Tiing Leong
authors.initials: TL
authors.lastname: Ang
authors.forename: Salem
authors.initials: S
authors.lastname: Omar
authors.forename: Hisao
authors.initials: H
authors.lastname: Tajiri
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000000981:diagnostic imaging*; D002277:Carcinoma / Q000000981:diagnostic imaging*; D003287:Contrast Media; D003937:Diagnosis, Differential; D019160:Endosonography / Q000379:methods*; D005260:Female; D005290:Ferric Compounds; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007501:Iron; D008297:Male; D008875:Middle Aged; D010087:Oxides; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging*; D010195:Pancreatitis / Q000000981:diagnostic imaging* / Q000276:immunology; D012372:ROC Curve; D012189:Retrospective Studies; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D010087:Oxides; C069727:Sonazoid; D007501:Iron