title: Technical optimization of four-channel multidetector-row helical computed tomography for depicting arterial stenosis: a phantom study.
abstract: OBJECTIVE
  To determine the effects of detector configuration, as well as vessel orientation, on the depiction accuracy of arterial stenosis using four-channel multidetector-row helical computed tomography (MDCT) angiography in vitro.
  
  
  METHODS
  Five acrylic vessel phantoms (3 mm in diameter with 25 or 50% stenosis, or 5 mm with 25, 50, or 75% stenosis) were scanned with a four-channel MDCT scanner at five vessel orientations (0, 30, 45, 60, and 90 degrees to the z-axis) using 4 x 1.25, 2.5, 3.75, and 5.0-mm detector configurations at beam pitches of 0.75 and 1.5. The percentage of stenosis was calculated by the ratio of the full width at half maximum for stenotic and non-stenotic portions of the phantom, and compared to the actual known values.
  
  
  RESULTS
  A detector configuration of 4 x 1.25 mm provided good reproducibility, as well as high accuracy for assessing vessel stenosis, while a 4 x 2.5-mm or wider detector configuration caused underestimations of stenosis. Although the phantoms perpendicular to the z-axis were underestimated, the errors were kept in clinically acceptable ranges using the 4 x 1.25-mm detector configuration.
  
  
  CONCLUSIONS
  Four-channel MDCT accurately discerns stenosis for vessel phantoms of 3 or 5 mm in diameter at any orientation when using a detector configuration of 4 x 1.25 mm.
authors.affiliation: Department of Clinical Informative Imageology, Osaka University Graduate School of Medicine, Osaka, Japan. s.takahashi@rad.umcn.nl
authors.forename: S
authors.initials: S
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Takamura
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.forename: M
authors.initials: M
authors.lastname: Kudo
authors.forename: Y
authors.initials: Y
authors.lastname: Narumi
authors.forename: T
authors.initials: T
authors.lastname: Murakami
authors.forename: H
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging*; D006801:Humans; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D036542:Tomography, Spiral Computed / Q000379:methods*