title: Reproducibility of a peripheral quantitative computed tomography scan protocol to measure the material properties of the second metatarsal.
abstract: BACKGROUND
  Peripheral quantitative computed tomography (pQCT) is an established technology that allows for the measurement of the material properties of bone. Alterations to bone architecture are associated with an increased risk of fracture. Further pQCT research is necessary to identify regions of interest that are prone to fracture risk in people with chronic diseases. The second metatarsal is a common site for the development of insufficiency fractures, and as such the aim of this study was to assess the reproducibility of a novel scanning protocol of the second metatarsal using pQCT.
  
  
  METHODS
  Eleven embalmed cadaveric leg specimens were scanned six times; three times with and without repositioning. Each foot was positioned on a custom-designed acrylic foot plate to permit unimpeded scans of the region of interest. Sixty-six scans were obtained at 15% (distal) and 50% (mid shaft) of the second metatarsal. Voxel size and scan speed were reduced to 0.40 mm and 25 mm.sec(-1). The reference line was positioned at the most distal portion of the 2(nd) metatarsal. Repeated measurements of six key variables related to bone properties were subject to reproducibility testing. Data were log transformed and reproducibility of scans were assessed using intraclass correlation coefficients (ICC) and coefficients of variation (CV%).
  
  
  RESULTS
  Reproducibility of the measurements without repositioning were estimated as: trabecular area (ICC 0.95; CV% 2.4), trabecular density (ICC 0.98; CV% 3.0), Strength Strain Index (SSI) - distal (ICC 0.99; CV% 5.6), cortical area (ICC 1.0; CV% 1.5), cortical density (ICC 0.99; CV% 0.1), SSI - mid shaft (ICC 1.0; CV% 2.4). Reproducibility of the measurements after repositioning were estimated as: trabecular area (ICC 0.96; CV% 2.4), trabecular density (ICC 0.98; CV% 2.8), SSI - distal (ICC 1.0; CV% 3.5), cortical area (ICC 0.99; CV%2.4), cortical density (ICC 0.98; CV% 0.8), SSI - mid shaft (ICC 0.99; CV% 3.2).
  
  
  CONCLUSIONS
  The scanning protocol generated excellent reproducibility for key bone properties measured at the distal and mid-shaft regions of the 2(nd) metatarsal. This protocol extends the capabilities of pQCT to evaluate bone quality in people who may be at an increased risk of metatarsal insufficiency fractures.
authors.forename: Elodie
authors.initials: E
authors.lastname: Chaplais
authors.forename: David
authors.initials: D
authors.lastname: Greene
authors.forename: Anita
authors.initials: A
authors.lastname: Hood
authors.forename: Scott
authors.initials: S
authors.lastname: Telfer
authors.forename: Verona
authors.initials: V
authors.lastname: du Toit
authors.forename: Davinder
authors.initials: D
authors.lastname: Singh-Grewal
authors.forename: Joshua
authors.initials: J
authors.lastname: Burns
authors.forename: Keith
authors.initials: K
authors.lastname: Rome
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Schiferl
authors.affiliation: Institute for Applied Health Research, Glasgow Caledonian University, Glasgow G4 0BA, UK. gordon.hendry@gcu.ac.uk.
authors.forename: Gordon J
authors.initials: GJ
authors.lastname: Hendry
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D002102:Cadaver; D006801:Humans; D008297:Male; D008682:Metatarsal Bones / Q000000981:diagnostic imaging*; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*