title: Local staging of pancreatic cancer: criteria for unresectability of major vessels as revealed by pancreatic-phase, thin-section helical CT.
abstract: OBJECTIVE
  This study was conducted to determine the criteria for unresectability of major peripancreatic vessels in patients with pancreatic carcinoma as revealed by optimally enhanced, pancreatic-phase thin-section helical CT.
  
  
  METHODS
  Twenty-five patients with pancreatic adenocarcinoma who underwent local dissection during curative or palliative surgery also underwent preoperative pancreatic-phase thin-section helical CT (40- to 70-sec delay, 2.5- to 3-mm collimation). Tumor involvement of the portal and superior mesenteric veins and the celiac, hepatic, and superior mesenteric arteries was prospectively graded on a 0-4 scale based on circumferential contiguity of tumor to vessel. Subsequent surgical results were then correlated with the CT grades.
  
  
  RESULTS
  At surgery, definitive evaluation was possible for 80 vessels. Forty-eight of 48 vessels graded 0 and three of three vessels graded 1 were resectable. Four of seven vessels graded 2, seven of eight vessels graded 3, and 14 of 14 vessels graded 4 were unresectable. A threshold of between grades 2 and 3, which corresponded to tumor involvement of one-half circumference of the vessel, yielded the lowest number of false-negatives and an acceptable number of false-positives for unresectability. Such a threshold would have yielded a sensitivity of 84%, a specificity of 98%, a positive predictive value of 95%, and a negative predictive value of 93% for unresectability of the vessels studied.
  
  
  CONCLUSIONS
  A grading system for tumor involvement of the major vessels in patients with pancreatic adenocarcinoma can be based on the degree of circumferential contiguity of tumor to vessel. Involvement of vessel to tumor that exceeds one-half circumference of the vessel is highly specific for unresectable tumor.
authors.affiliation: Department of Radiological Sciences, University of California School of Medicine, Medical Center, Los Angeles 90095-1721, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Lu
authors.forename: H A
authors.initials: HA
authors.lastname: Reber
authors.forename: R M
authors.initials: RM
authors.lastname: Krasny
authors.forename: B M
authors.initials: BM
authors.lastname: Kadell
authors.forename: J
authors.initials: J
authors.lastname: Sayre
mesh_terms: D000230:Adenocarcinoma / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010179:Pancreas / Q000098:blood supply* / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000601:surgery; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*