title: Improved vascular opacification in cerebral computed tomography angiography with 80 kVp.
abstract: OBJECTIVE
  We sought to intraindividually compare computed tomography angiographies (CTAs) acquired at 80 kVp and 120 kVp with respect to vessel contrast, noise level, and radiation dose.
  
  
  METHODS
  CTA was performed on a single-slice CT scanner using tube voltages of 80 kVp and 120 kVp in 29 patients with arteriovenous malformations. Mean Hounsfield Units (HU) were evaluated for different vessels and brain parenchyma. To determine contrast-to-noise ratios (CNRs), noise levels were estimated from phantom measurements.
  
  
  RESULTS
  The calculated effective dose to male/female patients was 0.4/0.5 mSv for 80 kVp and 0.7/0.8 mSv for 120 kVp. CT density in blood vessels was between 297 and 458 HU for 80 kVp and 152 and 229 HU for 120 kVp (P<0.0001). Despite an increased noise level in the low-voltage images, the CNR was 26-59% higher at 80 kVp than at 120 kVp (P<0.05).
  
  
  CONCLUSIONS
  The use of a reduced tube potential leads to improved CNR in CTA of the cerebral vasculature and a markedly reduced radiation exposure to patients.
authors.affiliation: Department of Radiology (E010), Deutsches Krebsforschungs-zentrum, Heidelberg, Germany.
authors.forename: Malte L
authors.initials: ML
authors.lastname: Bahner
authors.forename: Andreas
authors.initials: A
authors.lastname: Bengel
authors.forename: Gunnar
authors.initials: G
authors.lastname: Brix
authors.forename: Ivan
authors.initials: I
authors.lastname: Zuna
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Kauczor
authors.forename: Stefan
authors.initials: S
authors.lastname: Delorme
mesh_terms: D000328:Adult; D002533:Cerebral Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D019047:Phantoms, Imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*