title: Arterial versus portal venous helical CT for revealing pancreatic adenocarcinoma: conspicuity of tumor and critical vascular anatomy.
abstract: OBJECTIVE
  The purpose of this study was to determine the conspicuity of pancreatic adenocarcinoma and surrounding critical pancreatic vascular structures on helical CT scans obtained during the arterial and portal venous phases of enhancement.
  
  
  METHODS
  Forty patients with pancreatic adenocarcinomas under-went dual-phase helical CT (3-mm collimation; l-mm overlapping reconstructions; 160 ml contrast medium injected at 4 ml/sec; scan delay: 18 sec for arterial phase, 60 sec for portal venous phase). Tissue enhancement and differences in tumor-to-pancreas contrast were compared. Quantitative evaluation was also done for the aorta, the superior mesenteric artery and vein, and the splenic and portal veins.
  
  
  RESULTS
  Tumor conspicuity was significantly greater in the portal venous phase, when the tumor-to-pancreas contrast difference was 54 +/- 31 H, than in the arterial phase, when the difference was 31 +/- 29 H. Enhancement values of critical pancreatic venous structures were significantly greater in the portal venous phase than in the arterial phase.
  
  
  CONCLUSIONS
  Arterial-phase helical CT in patients with pancreatic adenocarcinoma is of limited benefit: lesion conspicuity is suboptimal and depiction of venous anatomy is inferior to the depiction possible with venous-phase helical CT.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston 02114, USA.
authors.forename: O
authors.initials: O
authors.lastname: Graf
authors.forename: G W
authors.initials: GW
authors.lastname: Boland
authors.forename: A L
authors.initials: AL
authors.lastname: Warshaw
authors.forename: C
authors.initials: C
authors.lastname: Fernandez-del-Castillo
authors.forename: P F
authors.initials: PF
authors.lastname: Hahn
authors.forename: P R
authors.initials: PR
authors.lastname: Mueller
mesh_terms: D000230:Adenocarcinoma / Q000098:blood supply / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007472:Iohexol; D008297:Male; D017538:Mesenteric Artery, Superior / Q000000981:diagnostic imaging; D008875:Middle Aged; D010179:Pancreas / Q000098:blood supply / Q000000981:diagnostic imaging; D010190:Pancreatic Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging*; D011169:Portal Vein / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007472:Iohexol