title: Automatic bone removal technique in whole-body dual-energy CT angiography: performance and image quality.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the efficiency of automatic bone removal in dual-energy CT angiography (CTA) of the trunk.
  
  
  METHODS
  Nineteen patients underwent dual-energy CTA of the trunk (tube A, 140 kV; tube B, 100 kV). In addition to the dual-energy dataset, an image equivalent to that of a standard 120-kV single-energy examination was generated with both tubes. Automated bone segmentation was performed on both datasets, and the results were analyzed. The time required for and subjective image quality of the maximum intensity projections (MIPs) generated were evaluated.
  
  
  RESULTS
  Errors in bone segmentation were found for 1.5% of bones on dual-energy images and 12.4% of bones on single-energy images (p < 0.01). The most important differences were found in the rib cage, sternum, and pelvis. The times required for postprocessing of MIPs were similar for the dual-energy (113.5 seconds) and single-energy (106.8 seconds) techniques. The subjective image quality of the arteries was considered better for dual-energy CTA (4.5 points) than for single-energy CTA (4.1 points) owing to false cutoff of vessels during the bone removal process on the single-energy images (p = 0.026).
  
  
  CONCLUSIONS
  For CTA of the trunk, the dual-energy postprocessing capabilities for 3D visualization are superior to the threshold-based bone removal of single-energy CT. Dual-energy CTA can generate boneless MIP images of substantial quality.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Haus 23 C UG, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany. boris.schell@googlemail.com
authors.forename: Boris
authors.initials: B
authors.lastname: Schulz
authors.forename: Katharina
authors.initials: K
authors.lastname: Kuehling
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kromen
authors.forename: Petra
authors.initials: P
authors.lastname: Siebenhandl
authors.forename: Matthias Josef
authors.initials: MJ
authors.lastname: Kerl
authors.forename: Thomas Josef
authors.initials: TJ
authors.lastname: Vogl
authors.forename: Ralf
authors.initials: R
authors.lastname: Bauer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000783:Aneurysm / Q000000981:diagnostic imaging; D015901:Angiography, Digital Subtraction / Q000379:methods*; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011857:Radiographic Image Interpretation, Computer-Assisted; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*; D051598:Whole Body Imaging