title: Small hypervascular hepatocellular carcinoma revealed by double arterial phase CT performed with single breath-hold scanning and automatic bolus tracking.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the usefulness of double arterial phase CT for the detection of small hypervascular hepatocellular carcinomas, using an automated bolus-tracking technique to initiate the hepatic arterial phase CT.
  
  
  METHODS
  Double arterial and late phase contrast-enhanced helical CT scans were obtained on 287 consecutive patients suspected of having hepatocellular carcinoma. These included 56 patients with 90 small (< or 3 cm) hepatocellular carcinomas and 50 patients with no hepatocellular carcinomas. CT scans of these patients were interpreted by three reviewers. The first arterial phase scan was initiated automatically 10 sec after the bolus-tracking program detected the threshold enhancement of 50 H in the abdominal aorta. Three reviewers interpreted the late phase CT scans in combination with the first, second, or both hepatic arterial phases. Measures of the reviewers' detection of hepatocellular carcinoma included analysis of interobserver variation, sensitivity, specificity, and area under receiver operating characteristic curve (A(z)).
  
  
  RESULTS
  The time elapsed from bolus initiation to threshold aortic enhancement ranged from 10 to 24 sec (mean, 13 sec), resulting in initiation of the first arterial phase CT scan from 20 to 34 sec (mean, 23 sec). The combination of late phase CT and both first and second arterial phase images showed significantly better performance than the combination of the late phase and either the first or second arterial phases, although the difference was most evident in comparison with the combination of second arterial and late phases.
  
  
  CONCLUSIONS
  An automated bolus-tracking program can be used to optimize the timing of hepatic arterial phase CT. Multiphasic CT performed using this technique is useful in detection of small hepatocellular carcinoma.
authors.affiliation: Department of Radiology, D1 Osaka University Medical School, 2-2 Yamadaoka, Suita City, Osaka 565-0871, Japan.
authors.forename: Tonsok
authors.initials: T
authors.lastname: Kim
authors.forename: Takamichi
authors.initials: T
authors.lastname: Murakami
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hori
authors.forename: Manabu
authors.initials: M
authors.lastname: Takamura
authors.forename: Satoru
authors.initials: S
authors.lastname: Takahashi
authors.forename: Atsuya
authors.initials: A
authors.lastname: Okada
authors.forename: Shuji
authors.initials: S
authors.lastname: Kawata
authors.forename: Modesto
authors.initials: M
authors.lastname: Cruz
authors.forename: Michael P
authors.initials: MP
authors.lastname: Federle
authors.forename: Hironobu
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000000981:diagnostic imaging; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media