title: Coronary artery calcium scoring with multislice computed tomography: in vitro assessment of a low tube voltage protocol.
abstract: OBJECTIVE
  We sought to compare an 80-kVp coronary calcium scoring protocol with the standard protocol of 120 kVp in terms of accuracy and reproducibility and to assess its dose reduction potential.
  
  
  METHODS
  An anthropomorphic heart phantom with calcium cylinders was scanned with different tube currents at 80 kVp and 120 kVp using a 16-slice multislice CT (MSCT) scanner. An adapted threshold for 80 kVp was calculated. Accuracy and reproducibility for calcium mass, volume, and Agatston score were analyzed using F-tests. The radiation doses needed to produce artifact-free images were determined.
  
  
  RESULTS
  Accuracy (measurement errors: mass 120 kVp +4.6%, mass 80 kVp -6.9%, volume 120 kVp +78.8%, volume 80 kVp +58.2%) and reproducibility (F-tests: mass: P = 0.4998, volume: P = 0.9168, Agatston: P = 0.5422) were comparable at both tube voltages. Avoiding the appearance of artificial lesions, a CTDI(w,eff) of 10.7 mGy was needed at 120 kVp versus 4.6 mGy at 80 kVp (dose reduction of 57%).
  
  
  CONCLUSIONS
  Using an 80-kVp protocol in coronary calcium scoring, a relevant dose reduction is possible without compromising reproducibility and accuracy.
authors.affiliation: Department of Diagnostic Radiology, University Hospital, RWTH-Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany. christoph.thomas@rwth-aachen.de
authors.forename: Christoph K
authors.initials: CK
authors.lastname: Thomas
authors.forename: Georg
authors.initials: G
authors.lastname: Mühlenbruch
authors.forename: Joachim E
authors.initials: JE
authors.lastname: Wildberger
authors.forename: Christian
authors.initials: C
authors.lastname: Hohl
authors.forename: Marco
authors.initials: M
authors.lastname: Das
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Günther
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Mahnken
mesh_terms: D000704:Analysis of Variance; D002114:Calcinosis / Q000000981:diagnostic imaging*; D002118:Calcium / Q000032:analysis*; D002138:Calibration; D019047:Phantoms, Imaging; D012372:ROC Curve; D011829:Radiation Dosage; D015203:Reproducibility of Results; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards*
chemical_list: D002118:Calcium