title: Dual-Energy Computed Tomography Angiography of the Head and Neck With Single-Source Computed Tomography: A New Technical (Split Filter) Approach for Bone Removal.
abstract: Dual-energy computed tomographic angiography (DE-CTA) has been demonstrated to improve the visualization of the head and neck vessels. The aim of this study was to test the potential of split-filter single-source dual-energy CT to automatically remove bone from the final CTA data set.
  
  
  
  Dual-energy CTA was performed in 50 consecutive patients to evaluate the supra-aortic arteries, either to grade carotid artery stenosis or to rule out traumatic dissections. Dual-energy CTA was performed on a 128-slice single-source CT system equipped with a special filter array to separate the 120-kV spectrum into a high- and a low-energy spectrum for DE-based automated bone removal. Image quality of fully automated bone suppression and subsequent manual optimization was evaluated by 2 radiologists on maximum intensity projections using a 4-grade scoring system. The effect of image reconstruction with an iterative metal artifact reduction algorithm on DE postprocessing was tested using a 3-grade scoring system, and the time demand for each postprocessing step was measured.
  
  
  
  Two patients were excluded due to insufficient arterial contrast enhancement; in the remaining 48 patients, automated bone removal could be performed successfully. The addition of iterative metal artifact reduction algorithm improved image quality in 58.3% of the cases. After manual optimization, DE-CTA image quality was rated excellent in 7, good in 29, and moderate in 10 patients. Interobserver agreement was high (κ = 0.85). Stenosis grading was not influenced using DE-CTA with bone removal as compared with the original CTA. The time demand for DE image reconstruction was significantly higher than for single-energy reconstruction (42.1 vs 20.9 seconds).
  
  
  
  Our results suggest that bone removal in DE-CTA of the head and neck vessels with a single-source CT is feasible and can be performed within acceptable time and moderate user interaction.
authors.affiliation: From the *Department of Radiology, University Hospital Erlangen-Nuremberg, Erlangen; and †Siemens AG, Healthcare Sector, Forchheim, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Kaemmerer
authors.forename: Michael
authors.initials: M
authors.lastname: Brand
authors.forename: Matthias
authors.initials: M
authors.lastname: Hammon
authors.forename: Matthias
authors.initials: M
authors.lastname: May
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wuest
authors.forename: Bernhard
authors.initials: B
authors.lastname: Krauss
authors.forename: Michael
authors.initials: M
authors.lastname: Uder
authors.forename: Michael M
authors.initials: MM
authors.lastname: Lell
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D016477:Artifacts; D001842:Bone and Bones; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D020212:Carotid Artery Injuries / Q000000981:diagnostic imaging*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D000072226:Computed Tomography Angiography / Q000379:methods*; D003287:Contrast Media; D005260:Female; D006257:Head / Q000098:blood supply / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007479:Iopamidol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000098:blood supply / Q000000981:diagnostic imaging; D011856:Radiographic Image Enhancement / Q000379:methods; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol