title: Accuracy of bone mineral density quantification using dual-layer spectral detector CT: a phantom study.
abstract: OBJECTIVE
  To investigate the accuracy of bone mineral density (BMD) quantification using dual-layer spectral detector CT (SDCT) at various scan protocols.
  
  
  METHODS
  Two validated anthropomorphic phantoms containing inserts of 50-200 mg/cm3calcium hydroxyapatite (HA) were scanned using a 64-slice SDCT scanner at various acquisition protocols (120 and 140 kVp, and 50, 100 and 200 mAs). Regions of interest (ROIs) were placed in each insert and mean attenuation profiles at monochromatic energy levels (90-200 keV) were constructed. These profiles were fitted to attenuation profiles of pure HA and water to calculate HA concentrations. For comparison, one phantom was scanned using dual energy X-ray absorptiometry (DXA).
  
  
  RESULTS
  At both 120 and 140 kVp, excellent correlations (R = 0.97, P < 0.001) were found between true and measured HA concentrations. Mean error for all measurements at 120 kVp was -5.6 ± 5.7 mg/cm3(-3.6 ± 3.2%) and at 140 kVp -2.4 ± 3.7 mg/cm3(-0.8 ± 2.8%). Mean measurement errors were smaller than 6% for all acquisition protocols. Strong linear correlations (R2≥ 0.970, P < 0.001) with DXA were found.
  
  
  CONCLUSIONS
  SDCT allows for accurate BMD quantification and potentially opens up the possibility for osteoporosis evaluation and opportunistic screening in patients undergoing SDCT for other clinical indications. However, patient studies are needed to extend and translate our findings.
  
  
  CONCLUSIONS
  • Dual-layer spectral detector CT allows for accurate bone mineral density quantification. • BMD measurements on SDCT are strongly linearly correlated to DXA. • SDCT, acquired for several indications, may allow for evaluation of osteoporosis. • This potentially opens up the possibility for opportunistic osteoporosis screening.
authors.affiliation: Department of Radiology, University Medical Centre Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands. R.W.vanHamersvelt-3@umcutrecht.nl.
authors.forename: Robbert W
authors.initials: RW
authors.lastname: van Hamersvelt
authors.affiliation: Department of Radiology, University Medical Centre Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
authors.forename: Arnold M R
authors.initials: AMR
authors.lastname: Schilham
authors.affiliation: Institute of Medical Physics, University of Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Engelke
authors.affiliation: Department of Radiology, University Medical Centre Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
authors.forename: Annemarie M
authors.initials: AM
authors.lastname: den Harder
authors.affiliation: Department of Nuclear Medicine, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: Bart
authors.initials: B
authors.lastname: de Keizer
authors.affiliation: Department of Geriatric Medicine, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: Harald J
authors.initials: HJ
authors.lastname: Verhaar
authors.affiliation: Department of Radiology, University Medical Centre Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
authors.forename: Tim
authors.initials: T
authors.lastname: Leiner
authors.affiliation: Department of Radiology, University Medical Centre Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
authors.forename: Pim A
authors.initials: PA
authors.lastname: de Jong
authors.affiliation: Department of Radiology, University Medical Centre Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Willemink
mesh_terms: D015502:Absorptiometry, Photon; D015519:Bone Density; D006801:Humans; D010024:Osteoporosis / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Bone mineral density; Dual energy X-Ray absorptiometry; Dual-energy CT; Dual-layer spectral detector CT; Material decomposition