title: Peripheral quantitative computed tomography: measurement sensitivity in persons with and without spinal cord injury.
abstract: OBJECTIVE
  To determine (1) the error attributable to external tibia-length measurements by using peripheral quantitative computed tomography (pQCT) and (2) the effect these errors have on scan location and tibia trabecular bone mineral density (BMD) after spinal cord injury (SCI).
  
  
  METHODS
  Blinded comparison and criterion standard in matched cohorts.
  
  
  METHODS
  Primary care university hospital.
  
  
  METHODS
  Eight able-bodied subjects underwent tibia length measurement. A separate cohort of 7 men with SCI and 7 able-bodied age-matched male controls underwent pQCT analysis.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  The projected worst-case tibia-length-measurement error translated into a pQCT slice placement error of +/-3 mm. We collected pQCT slices at the distal 4% tibia site, 3 mm proximal and 3 mm distal to that site, and then quantified BMD error attributable to slice placement.
  
  
  RESULTS
  Absolute BMD error was greater for able-bodied than for SCI subjects (5.87 mg/cm(3) vs 4.5 mg/cm(3)). However, the percentage error in BMD was larger for SCI than able-bodied subjects (4.56% vs 2.23%).
  
  
  CONCLUSIONS
  During cross-sectional studies of various populations, BMD differences up to 5% may be attributable to variation in limb-length-measurement error.
authors.affiliation: Graduate Program in Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA 52242-1190, USA. richard-shields@uiowa.edu
authors.forename: Richard K
authors.initials: RK
authors.lastname: Shields
authors.forename: Shauna
authors.initials: S
authors.lastname: Dudley-Javoroski
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Boaldin
authors.forename: Trent A
authors.initials: TA
authors.lastname: Corey
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Fog
authors.forename: Jacquelyn M
authors.initials: JM
authors.lastname: Ruen
mesh_terms: D000328:Adult; D000368:Aged; D015519:Bone Density; D015331:Cohort Studies; D005260:Female; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008875:Middle Aged; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D013977:Tibia / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed