title: Optimal scan timing for artery-vein separation at whole-brain CT angiography using a 320-row MDCT volume scanner.
abstract: OBJECTIVE
  A 320-row multidetector CT (MDCT) is expected for a good artery-vein separation in terms of temporal resolution. However, a shortened scan duration may lead to insufficient vascular enhancement. We assessed the optimal scan timing for the artery-vein separation at whole-brain CT angiography (CTA) when bolus tracking was used at 320-row MDCT.
  
  
  METHODS
  We analyzed 60 patients, who underwent whole-brain four-dimensional CTA. Difference in CT attenuation between the internal carotid artery (ICA) and the superior sagittal sinus (Datt) was calculated in each phase. Using a visual evaluation score for the depiction of arteries and veins, we calculated the difference between the mean score for the intracranial arteries and the mean score for the veins (Dscore). We assessed the time at which the maximum Dattand Dscorewere simultaneously observed.
  
  
  RESULTS
  The maximum Dattwas observed at 6.0 s and 8.0 s in the arterial-dominant phase and at 16.0 s and 18.0 s in the venous-dominant phase after the contrast media arrival time at the ICA (Taa). The maximum Dscorewas observed at 6.0 s and 8.0 s in the arterial-dominant phase and at 16.0 s in the venous-dominant phase after the Taa. There were no statistically significant differences in Datt(p = 0.375) or Dscore(p = 0.139) between these scan timings.
  
  
  CONCLUSIONS
  The optimal scan timing for artery-vein separation at whole-brain CTA was 6.0 s or 8.0 s for the arteries and 16.0 s for the veins after the Taa. Advances in knowledge: Optimal scan timing allowed us to visualize intracranial arteries or veins with minimal superimposition.
authors.affiliation: 1 Department of Medical Technology, Division of Radiology, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Shirasaka
authors.affiliation: 2 Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Hiwatashi
authors.affiliation: 2 Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yamashita
authors.affiliation: 1 Department of Medical Technology, Division of Radiology, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kondo
authors.affiliation: 1 Department of Medical Technology, Division of Radiology, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hamasaki
authors.affiliation: 1 Department of Medical Technology, Division of Radiology, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Yamato
authors.initials: Y
authors.lastname: Shimomiya
authors.affiliation: 1 Department of Medical Technology, Division of Radiology, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: 3 Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Funama
authors.affiliation: 2 Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001158:Arteries / Q000000981:diagnostic imaging; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging*; D001931:Brain Mapping / Q000379:methods; D000072226:Computed Tomography Angiography / Q000295:instrumentation / Q000379:methods*; D054893:Cone-Beam Computed Tomography / Q000379:methods; D005260:Female; D056973:Four-Dimensional Computed Tomography / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000295:instrumentation / Q000379:methods*; D011446:Prospective Studies; D013997:Time Factors; D015898:Tomography Scanners, X-Ray Computed; D014680:Veins / Q000000981:diagnostic imaging; D055815:Young Adult