title: Coronary calcium quantification using various calibration phantoms and scoring thresholds.
abstract: OBJECTIVE
  To compare scoring threshold and calibration method-dependent accuracy and variability of coronary calcium measurements by multidetector computed tomography (MDCT).
  
  
  METHODS
  Ninety-five subjects were scanned with MDCT. We calculated Agatston score and volume score. Mineral mass (MM) was calculated using patient-based and scanner-based calibration methods. Accuracy of calibration was validated using artificial calcium cylinders.
  
  
  RESULTS
  Patient-based and scanner-based calibration permitted accurate quantification of artificial calcium cylinders (bias: 0 mg and -2 mg). In the subjects, the mean relative difference of MM measurements performed at 90 and 130 Hounsfield units threshold (59%) was lower than for Agatston score (94%) and volume score (109%; P < 0.05). Patient-based and scanner-based calibration yielded systematically different MM measurements (bias: 22%).
  
  
  CONCLUSIONS
  MM lowers threshold-dependent variability of coronary calcium measurements. Patient-based and scanner-based calibration allows accurate calcium quantification ex vivo but reveal systematic differences in subjects. Patient-based calibration may better account for subject size and composition.
authors.affiliation: Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 100 Charles River Plaza, Suite 400, Boston, MA 02114, USA. maros_ferencik@hms.harvard.edu
authors.forename: Maros
authors.initials: M
authors.lastname: Ferencik
authors.forename: Ashley
authors.initials: A
authors.lastname: Ferullo
authors.forename: Stephan
authors.initials: S
authors.lastname: Achenbach
authors.forename: Suhny
authors.initials: S
authors.lastname: Abbara
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Chan
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Booth
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Brady
authors.forename: Udo
authors.initials: U
authors.lastname: Hoffmann
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000032:analysis*; D002138:Calibration; D017023:Coronary Angiography / Q000379:methods*; D003331:Coronary Vessels / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D002118:Calcium