title: Bone subtraction CTA for transcranial arteries: intra-individual comparison with standard CTA without bone subtraction and TOF-MRA.
abstract: OBJECTIVE
  To evaluate the impact of bone subtraction computed tomography angiography (BS-CTA) for the assessment of transcranial arteries in comparison with standard CTA (S-CTA) without bone removal and time-of-flight magnetic resonance angiography (TOF-MRA).
  
  
  METHODS
  Cranial unenhanced CT and S-CTA were performed in 53 patients with suspected cerebrovascular disease. BS-CTA datasets were reconstructed from the S-CTA and unenhanced CT source images. TOF-MRA was performed within 24h after CTA on a 1.5 T MRI system. Two radiologists, in consensus, evaluated the segments of the internal carotid artery (C2-C7), the vertebral artery (V4), and the basilar artery for the degree of stenosis. A five-step scale (0-49, 50-69, 70-89, 90-99% and occlusion) for the degree of stenosis was applied for all segments. Wilcoxon's signed rank test was used for statistical analysis.
  
  
  RESULTS
  Seven hundred and fifty vessel segments (ICA:636, VA:106, BA:53) were analysed. The degree of stenosis on S-CTA was consistent with TOF-MRA in all segments. BS-CTA showed a trend towards higher stenosis scores in cases of calcified plaques compared to S-CTA (p=0.11) and TOF-MRA (p=0.09), which was not statistically significant. In transcranial segments, BS-CTA revealed equivalent scores compared to S-CTA and TOF-MRA (p=0.25; p=0.20).
  
  
  CONCLUSIONS
  BS-CTA produced similar results to TOF-MRA and S-CTA and can be applied as a non-invasive imaging method for the transcranial arteries. However, BS-CTA shows a trend towards overestimation of the degree of stenosis.
authors.affiliation: Department of Clinical Radiology, University of Muenster, Muenster, Germany. buerkeb@uni-muenster.de
authors.forename: B
authors.initials: B
authors.lastname: Buerke
authors.forename: M
authors.initials: M
authors.lastname: Puesken
authors.forename: G
authors.initials: G
authors.lastname: Wittkamp
authors.forename: C
authors.initials: C
authors.lastname: Stehling
authors.forename: H
authors.initials: H
authors.lastname: Ditt
authors.forename: P
authors.initials: P
authors.lastname: Seidensticker
authors.forename: J
authors.initials: J
authors.lastname: Wessling
authors.forename: W
authors.initials: W
authors.lastname: Heindel
authors.forename: S P
authors.initials: SP
authors.lastname: Kloska
mesh_terms: D015901:Angiography, Digital Subtraction / Q000379:methods*; D002533:Cerebral Angiography / Q000379:methods; D002536:Cerebral Arteries / Q000000981:diagnostic imaging* / Q000473:pathology; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012886:Skull / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods