title: Coronary calcium scores are systematically underestimated at a large chest size: A multivendor phantom study.
abstract: OBJECTIVE
  To evaluate the effect of chest size on coronary calcium score (CCS) as assessed with new-generation CT systems from 4 major vendors.
  
  
  METHODS
  An anthropomorphic, small-sized (300 × 200 mm) chest phantom containing 100 small calcifications (diameters, 0.5-2.0 mm) was evaluated with and without an extension ring on state-of-the-art CT systems from 4 vendors. The extension ring was used to mimic a patient with a large chest size (400 × 300 mm). Image acquisition was repeated 5 times with small translations and/or rotations. Routine clinical acquisition and reconstruction protocols for small and large patients were used. CCS was quantified as Agatston and mass scores with vendor software.
  
  
  RESULTS
  The small-sized phantom resulted in median (interquartiles) Agatston scores of 10 (9-35), 136 (123-146), 34 (30-37), and 87 (85-89) for Philips, GE, Siemens, and Toshiba, respectively. Mass scores were 4 mg (3-9 mg), 23 mg (21-27 mg), 8 mg (8-9 mg), and 20 mg (20-20 mg), respectively. Adding the extension ring resulted in reduced Agatston scores for all vendors (17%-48%) and mass scores for 2 vendors (11%-49%). Median Agatston scores decreased to 9 (5-10), 79 (60-80), 27 (24-32), and 45 (29-53) units, and median mass scores remained similar for Philips at 4 mg (4-6 mg) and Siemens at 8 mg (7-8 mg) and decreased for the other vendors to 13 mg (11-14 mg) and 10 mg (8-13 mg), respectively.
  
  
  CONCLUSIONS
  This multivendor phantom study showed that CCS can be underestimated up to 50% (49%-66%) for Agatston scores and 49% (36%-59%) for mass scores at a larger chest size, which may be relevant for women and large patients. However, CCS underestimation by chest size differs considerably by vendor.
authors.affiliation: Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, E01.132, Utrecht 3508 GA, The Netherlands. Electronic address: m.willemink@umcutrecht.nl.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Willemink
authors.affiliation: Department of Radiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Bronislaw
authors.initials: B
authors.lastname: Abramiuc
authors.affiliation: Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, E01.132, Utrecht 3508 GA, The Netherlands.
authors.forename: Annemarie M
authors.initials: AM
authors.lastname: den Harder
authors.affiliation: Department of Radiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Niels R
authors.initials: NR
authors.lastname: van der Werf
authors.affiliation: Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, E01.132, Utrecht 3508 GA, The Netherlands.
authors.forename: Pim A
authors.initials: PA
authors.lastname: de Jong
authors.affiliation: Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, E01.132, Utrecht 3508 GA, The Netherlands; Department of Radiology, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Ricardo P J
authors.initials: RP
authors.lastname: Budde
authors.affiliation: Department of Radiology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Joachim E
authors.initials: JE
authors.lastname: Wildberger
authors.affiliation: Department of Radiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Center for Medical Imaging North East Netherlands, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Rozemarijn
authors.initials: R
authors.lastname: Vliegenthart
authors.affiliation: Department of Radiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Tineke P
authors.initials: TP
authors.lastname: Willems
authors.affiliation: Department of Radiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Marcel J W
authors.initials: MJ
authors.lastname: Greuter
authors.affiliation: Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, E01.132, Utrecht 3508 GA, The Netherlands.
authors.forename: Tim
authors.initials: T
authors.lastname: Leiner
mesh_terms: D017023:Coronary Angiography / Q000295:instrumentation*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D004867:Equipment Design; D006801:Humans; D019047:Phantoms, Imaging; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012984:Software; D013909:Thorax / Q000033:anatomy & histology*; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*; D061205:Vascular Calcification / Q000000981:diagnostic imaging*
keywords: Agatston score; Chest size; Computed tomography; Coronary calcium score