title: Trabecular structure analysis using C-arm CT: comparison with MDCT and flat-panel volume CT.
abstract: OBJECTIVE
  This paper assesses interscan, interreader, and intrareader variability of C-arm CT and compares it to that of flat-panel volume-CT (fpVCT) and high-definition multi-detector-CT (HD-MDCT).
  
  
  METHODS
  Five cadaver knee specimens were imaged using C-arm-CT, fpVCT, and HD-MDCT. Apparent (app.) trabecular bone volume fraction (BV/TV), app. trabecular number (TbN), app. trabecular spacing (TbSp), and app. trabecular thickness (TbTh) of the proximal tibia were measured by three readers. Interreader, intrareader, and interscan variability for C-arm CT was expressed as coefficient of variation (CV), standard deviation (SD), and intraclass correlation coefficient (ICC).
  
  
  RESULTS
  With the exception of app.TbSp (CV: 7.05-9.35%, SD: 0.06-0.09, ICC: 0.89-0.94), the variability of C-arm CT was low (CV: 2.41-6.43%, SD: 0.01-0.048, ICC: 0.65-0.98). Its interreader reliability (CV: 2.66-4.55%, SD: 0.01-0.03, ICC: 0.81-0.95) was comparable to that of HD-MDCT (CV: 2.41-4.08%, SD: 0.014-0.016, ICC: 0.95-0.96), and fpVCT (CV: 3.13-5.63%, SD: 0.009-0.036, ICC: 0.64-0.98) for all parameters except app.TbSp.
  
  
  CONCLUSIONS
  C-arm CT is a reliable method for assessing trabecular bone architectural parameters with the exception of app.TbSp due to spatial resolution limitation.
authors.affiliation: Department of Radiology, Massachusetts General Hospital Neuroradiology, GRB-273A, 55 Fruit Street, Boston, MA 02114, USA. cmphan@partners.org
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Phan
authors.forename: Eric A
authors.initials: EA
authors.lastname: Macklin
authors.forename: Miriam A
authors.initials: MA
authors.lastname: Bredella
authors.forename: Monica
authors.initials: M
authors.lastname: Dadrich
authors.forename: Paul
authors.initials: P
authors.lastname: Flechsig
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Yoo
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Hirsch
authors.forename: Rajiv
authors.initials: R
authors.lastname: Gupta
mesh_terms: D000368:Aged; D002102:Cadaver; D054893:Cone-Beam Computed Tomography / Q000295:instrumentation / Q000379:methods; D006801:Humans; D015203:Reproducibility of Results; D013977:Tibia / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*