title: Helical CT of the liver: value of an early hepatic arterial phase.
abstract: OBJECTIVE
  To prospectively evaluate a dual-phase helical acquisition in computed tomography (CT) of the liver.
  
  
  METHODS
  Two helical CT acquisitions were performed in 103 patients: hepatic arterial phase (HAP) 15 seconds after injection of 2 mL/kg contrast material at a rate of 6 mL/sec and the portal venous phase (PVP) 90 seconds after injection. Detection of focal liver lesions, vascular anatomic features, and perfusion abnormalities were assessed by two reviewers. Liver enhancement was also calculated on every section.
  
  
  RESULTS
  Of 119 detected focal liver lesions, nine were seen during HAP only and 40 during PVP only. According to a 0-3 score, visualization of the arterial anatomic landmarks was better during HAP (P < .0001). Five right replaced and two left replaced hepatic arteries were visualized only during HAP. Parenchymal perfusion abnormalities were found in 32 patients during HAP and in four patients during PVP.
  
  
  CONCLUSIONS
  A dual-phase acquisition depicted 8% additional focal liver lesions and outlined the entire vasculature of the liver.
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001653:Bile Ducts, Intrahepatic / Q000000981:diagnostic imaging; D003287:Contrast Media / Q000008:administration & dosage; D005069:Evaluation Studies as Topic; D005260:Female; D006499:Hepatic Artery / Q000000981:diagnostic imaging*; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage; D007479:Iopamidol / Q000008:administration & dosage; D007482:Iothalamate Meglumine / Q000008:administration & dosage; D008099:Liver / Q000098:blood supply / Q000000981:diagnostic imaging*; D008102:Liver Circulation; D008113:Liver Neoplasms / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011172:Portography; D011446:Prospective Studies; D011856:Radiographic Image Enhancement / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids / Q000008:administration & dosage
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; D007472:Iohexol; D007479:Iopamidol; C054871:ioversol; D007482:Iothalamate Meglumine