Calcified Tissue International

, Volume 56, Issue 3, pp 210–214 | Cite as

The accuracy of volumetric bone density measurements in dual X-ray absorptiometry

  • M. A. Sabin
  • G. M. Blake
  • S. M. MacLaughlin-Black
  • I. Fogelman
Clinical Investigations

Abstract

New developments in dual x-ray absorptiometry (DXA) allow the performance of high precision anteroposterior (AP) and lateral scans of spinal bone mineral density (BMD, units: g/cm2) without the patient moving from the supine position. Data from both projections may be combined to give an estimate of the true volumetric bone mineral density (VBMD, units: g/cm3) of the lumbar vertebral bodies. This report presents a cadaver study designed to validate DXA measurements of volumetric bone density. Sections of whole lumbar spine were scanned in AP and lateral projections in a water tank to simulate soft tissue. Individual vertebrae were then divided to separate the vertebral body from the neural arch, and vertebral body volume was measured using the displacement of sand. The bone mineral content (BMC) of vertebral bodies and neural arches was measured by ashing at 250°C for 60 hours followed by 500°C for a further 24 hours. The results showed that DXA scanning systematically underestimated ashing data by 14% for AP BMC, 33% for vertebral body BMC, 23% for vertebral body volume, and 12% for VBMD. Despite these significant systematic errors, the DXA measurements and ashing values were highly correlated (r=0.979-0.992). The results suggested that after allowing for the systematic errors, lateral DXA parameters related closely to true BMC, volume, and VBMD.

Key words

Bone mineral measurements Dual x-ray absorptiometry Volumetric bone density 

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Copyright information

© Springer-Verlag New York Inc. 1995

Authors and Affiliations

  • M. A. Sabin
    • 1
  • G. M. Blake
    • 2
  • S. M. MacLaughlin-Black
    • 1
  • I. Fogelman
    • 2
  1. 1.Division of Anatomy and Cell BiologyUMDS (Guy's Campus)LondonUK
  2. 2.Department of Nuclear MedicineGuy's HospitalLondonUK

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