title: Effect of varying slice thickness on coronary calcium scoring with multislice computed tomography in vitro and in vivo.
abstract: OBJECTIVE
  To compare coronary calcium scoring results (calcium volume, calcium mass, Agatston score, and number of lesions) of different slice thicknesses using a 16-slice CT (MSCT) scanner.
  
  
  METHODS
  A nonmoving anthropomorphic thorax phantom with calcium cylinders of different sizes and densities was scanned 30 times with repositioning applying a standardized retrospectively ECG-gated MSCT (SOMATOM Sensation 16; Siemens, Forchheim, Germany) scan protocol: collimation 12 x 0.75 mm, tube voltage 120 kV, effective tube current time-product 133 mAs(eff). Fifty patients (29 male; age 57.2 +/- 8.4 years) underwent a nonenhanced scan applying the same scan protocol. Two image sets (effective slice thicknesses 3 mm and 1 mm) were reconstructed at 60% of the RR interval. Image noise was measured in both studies. Calcium volume, calcium mass and Agatston score were calculated using a commercially available software tool.
  
  
  RESULTS
  Due to increased image noise in thinner slices, calcium scoring in all scans was performed applying a scoring threshold of 350 HU. In the phantom study, 1-mm slices showed significantly higher scoring results in respect to calcium volume (+8.2%), calcium mass (+12.5%), and Agatston score (+5.3%) (all P < 0.0001). In the patient study, 27 patients had coronary calcifications in 3-mm slices, and 31 patients had coronary calcifications in 1-mm slices. Thinner slices showed significantly higher scoring results in respect to volume (+47.1%), mass (+47.2%), and Agatston score (+29.7%) (all P < 0.0001).
  
  
  CONCLUSIONS
  When comparing 3-mm and 1-mm slices in coronary calcium scoring in MSCT, thinner slices lead to significantly increased scoring results.
authors.affiliation: Department of Diagnostic Radiology, University Hospital (RWTH), Aachen, Aachen, Germany. gmuhlen@rad.rwth-aachen.de
authors.forename: Georg
authors.initials: G
authors.lastname: Mühlenbruch
authors.forename: Christoph
authors.initials: C
authors.lastname: Thomas
authors.forename: Joachim E
authors.initials: JE
authors.lastname: Wildberger
authors.forename: Ralf
authors.initials: R
authors.lastname: Koos
authors.forename: Marco
authors.initials: M
authors.lastname: Das
authors.forename: Christian
authors.initials: C
authors.lastname: Hohl
authors.forename: Marcus
authors.initials: M
authors.lastname: Katoh
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Günther
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Mahnken
mesh_terms: D000368:Aged; D016477:Artifacts; D002114:Calcinosis / Q000000981:diagnostic imaging*; D002118:Calcium / Q000378:metabolism; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*
chemical_list: D002118:Calcium