title: UK reference data for the Hologic QDR Discovery dual-energy x ray absorptiometry scanner in healthy children and young adults aged 6-17 years.
abstract: BACKGROUND
  The use and correct interpretation of bone densitometry measurements in paediatric patients relies on the availability of appropriate reference data. Ideally, such data should be matched for sex, chronological age, height, weight, pubertal development and ethnicity.
  
  
  OBJECTIVE
  To provide UK-specific reference data for the Hologic QDR Discovery dual-energy x ray absorptiometry (DXA) scanners.
  
  
  METHODS
  Healthy, Caucasian children aged 5-18 years were recruited from local schools, colleges, general practitioner surgeries and staff from the University of Manchester, Manchester, UK. Suitable participants had DXA measurements taken of the lumbar spine, hip and total body. Sex-specific reference centile curves for bone mineral apparent density (BMAD; spine and femoral neck) are provided, using the approach suggested by Mølgaard et al. to interpret the scans. LMS (lambda, mu, varsigma) tables for calculation of individual standard deviation scores (SDSs) were produced; a weblink is provided to these tables to allow calculation of an individual child's SDSs.
  
  
  RESULTS
  The total study population consisted of 442 participants (239 male). The total numbers of scans available for analysis were 431 of the lumbar spine, 426 of the total body and 393 of the proximal femur. Data are provided for clinical interpretation of the spine and femoral neck scans based on BMAD (g/cm3), which reduces the size dependence of DXA areal bone mineral density (g/cm2). The spine and total-body data are also presented for interpretation of results using the approach suggested by Mølgaard et al.
  
  
  CONCLUSIONS
  This article provides the first sex-specific and ethnicity-specific reference databases for UK, which should allow the clinician to assess bone mineral density in paediatric patients, measured by the Hologic QDR Discovery DXA scanner.
authors.affiliation: Department of Clinical Radiology, Imaging Science and Biomedical Engineering, University of Manchester, Manchester, UK. kathryn.a.ward@manchester.ac.uk
authors.forename: Kate A
authors.initials: KA
authors.lastname: Ward
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Ashby
authors.forename: Steven A
authors.initials: SA
authors.lastname: Roberts
authors.forename: Judith E
authors.initials: JE
authors.lastname: Adams
authors.forename: M
authors.initials: M
authors.lastname: Zulf Mughal
mesh_terms: D015502:Absorptiometry, Photon / Q000295:instrumentation / Q000592:standards*; D000293:Adolescent; D015519:Bone Density / Q000502:physiology; D002648:Child; D015331:Cohort Studies; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000502:physiology; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000502:physiology; D008297:Male; D012016:Reference Values; D006113:United Kingdom