European Journal of Nuclear Medicine

, Volume 19, Issue 1, pp 41–46

Measurements of bone mineral density of the proximal femur by two commercially available dual energy X-ray absorptiometric systems

  • Ole Lander Svendsen
  • Ulla Marslew
  • Christian Hassager
  • Claus Christiansen
Original Articles

DOI: 10.1007/BF00178307

Cite this article as:
Svendsen, O.L., Marslew, U., Hassager, C. et al. Eur J Nucl Med (1992) 19: 41. doi:10.1007/BF00178307

Abstract

Two dual energy X-ray absorptiometric (DXA) instruments have recently become commercially available for local bone densitometry: the QDR-1000 (Hologic Inc.) and the DPX (Lunar Radiation Corp.). We report the precision, influence of femoral rotation, correlation and agreement of bone mineral measurements of the proximal femur by these two instruments. In vitro (femur phantom) short-term precision was 1.1%–3.5%, and the long-term precision was 1.2%–3.8%. In vivo (groups of 10 premenopausal and 10 postmenopausal women) short-term precision of duplicate measurements was 1.6%–4.7%, and long-term precision was 1.9%–5.5%. Overall, the precision for Ward's triangle was over 3% and that for the femoral neck and trochanter, 2%–3%. Rotation of a femur phantom produced a statistically significant change in the bone mineral density (BMD) of the femoral neck. Within a clinically relevant range of femoral rotation (20° inward rotation ±5°) the coefficient of variation (CV%) increased by a mean factor of 1.1–1.4. Although the correlation (r < 0.9) between BMD measurements of the proximal femur by the DPX and QDR-1000 in 30 postmenopausal women was high, there was lack of agreement between the two instruments. We found no statistically significant differences between the right and left femur in 30 postmenopausal women. A bilateral femur scan took a mean total time of about 22 min. We conclude that with the introduction of DXA instruments, the precision of bone mineral measurements of the proximal femur has improved. However, for comparability between commercially available DXA instruments, it might be advantageous if units were standardized.

Key words

Dual energy X-ray absorptiometryBone mineralProximal femurFemoral rotationPrecision

Copyright information

© Springer-Verlag 1992

Authors and Affiliations

  • Ole Lander Svendsen
    • 1
  • Ulla Marslew
    • 1
  • Christian Hassager
    • 1
  • Claus Christiansen
    • 1
  1. 1.Department of Clinical Chemistry, Glostrup HospitalUniversity of CopenhagenGlostrupDenmark