title: Detection of hypervascular hepatocellular carcinoma with multidetector-row CT: single arterial-phase imaging with computer-assisted automatic bolus-tracking technique compared with double arterial-phase imaging.
abstract: OBJECTIVE
  To compare single arterial-phase (SAP) computed tomography (CT) imaging with bolus tracking (BT) with double arterial-phase (DAP) CT imaging for detecting hypervascular hepatocellular carcinoma.
  
  
  METHODS
  The DAP images were obtained at 25 (DAP-early) and 40 seconds (DAP-late) after the start of contrast material injection. All patients underwent SAP-BT imaging where images were obtained 10 seconds after the CT attenuation value of the aorta reached the threshold value of 120 Hounsfield unit (HU) in 29 (group 120-HU), 160 HU in 30 (group 160-HU), and 200 HU in 32 patients (group 200-HU). Attenuation conspicuity with SAP-BT technique was compared with that with DAP technique using repeated-measures analysis of variance. Attenuation conspicuity and mean scan delays with SAP-BT images obtained with different threshold values were compared using analysis of variance. The sensitivities were compared using McNemar and Fisher exact tests.
  
  
  RESULTS
  Within all groups, mean attenuation conspicuity with SAP-BT and DAP-late was significantly higher than that with DAP-early. Regarding SAP-BT, mean attenuation conspicuity in group 200-HU (42 +/- 18 HU) was significantly higher than those in groups 120-HU (23 +/- 11 HU) and 160-HU (25 +/- 11 HU). Mean scan delays for SAP-BT were 24.2 seconds in group-120 HU, 26.8 seconds in group-160 HU, and 31.1 seconds in group-200 HU (P < 0.001). The mean sensitivity with SAP-BT technique in group 200-HU (92.7%) was significantly higher than those in groups 120-HU (72.4%) and 160-HU (71.1%).
  
  
  CONCLUSIONS
  Single arterial-phase CT scanning with bolus tracking can be effectively used to detect hepatocellular carcinoma when a threshold value of 200 HU is used.
authors.affiliation: First Department of Medicine, Yamanashi Medical University, Yamanashi, Japan.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kitamura
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Sukru Mehmet
authors.initials: SM
authors.lastname: Erturk
authors.forename: Hiroto
authors.initials: H
authors.lastname: Nakajima
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sou
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Araki
authors.forename: Shunichi
authors.initials: S
authors.lastname: Okada
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Enomoto
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000098:blood supply*; D006801:Humans; D008113:Liver Neoplasms / Q000098:blood supply* / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*