Dual energy X-ray absorptiometry of the knee in spinal cord injury: Methodology and correlation with quantitative computed tomography

J. G. McPherson; W. B. Edwards; A. Prasad; K. L. Troy; J. W. Griffith; T. J. Schnitzer

doi:10.1038/sc.2014.122

Dual energy X-ray absorptiometry of the knee in spinal cord injury: Methodology and correlation with quantitative computed tomography

J. G. McPherson, W. B. Edwards, A. Prasad, K. L. Troy, J. W. Griffith, T. J. Schnitzer^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

29 Scopus citations

Abstract

Study Design: Comparison of diagnostic tests; methodological validation. Objectives: Primary: to investigate the precision and reliability of a knee bone mineral density (BMD) assessment protocol that uses an existing dual energy X-ray absorptiometry (DXA) forearm acquisition algorithm in individuals with spinal cord injury (SCI). Secondary: to correlate DXA-based knee areal BMD with volumetric BMD assessments derived from quantitative computed tomography (QCT). Setting: Academic medical center, Chicago, IL, USA. Methods: Participants: a convenience sample of 12 individuals with acute SCI recruited for an observational study of bone loss and 34 individuals with chronic SCI who were screened for a longitudinal study evaluating interventions to increase BMD. Main outcome measures: root-mean-square standard deviation (RMS-SD) and intrainter-rater reliability of areal BMD acquired at three knee regions using an existing DXA forearm acquisition algorithm; correlation of DXA-based areal BMD with QCT-derived volumetric BMD. Results: The RMS-SD of areal BMD at the distal femoral epiphysis, distal femoral metaphysis and proximal tibial epiphysis averaged 0.021, 0.012 and 0.016 g cm^-2, respectively, in acute SCI and 0.018, 0.02 and 0.016 g cm^-2 in chronic SCI. All estimates of intra/inter-rater reliability exceeded 97% and DXA-based areal BMD was significantly correlated with QCT-derived volumetric BMD at all knee regions analyzed. Conclusions: Existing DXA forearm acquisition algorithms are sufficiently precise and reliable for short-term assessments of knee BMD in individuals with SCI. Future work is necessary to quantify the reliability of this approach in longitudinal investigations and to determine its ability to predict fractures and recovery potential.

Original language	English (US)
Pages (from-to)	821-825
Number of pages	5
Journal	Spinal Cord
Volume	52
Issue number	11
DOIs	https://doi.org/10.1038/sc.2014.122
State	Published - Nov 13 2014

Funding

Study Design: Comparison of diagnostic tests; methodological validation. Objectives: Primary: to investigate the precision and reliability of a knee bone mineral density (BMD) assessment protocol that uses an existing dual energy X-ray absorptiometry (DXA) forearm acquisition algorithm in individuals with spinal cord injury (SCI). Secondary: to correlate DXA-based knee areal BMD with volumetric BMD assessments derived from quantitative computed tomography (QCT). Setting: Academic medical center, Chicago, IL, USA. Methods: Participants: a convenience sample of 12 individuals with acute SCI recruited for an observational study of bone loss and 34 individuals with chronic SCI who were screened for a longitudinal study evaluating interventions to increase BMD. Main outcome measures: root-mean-square standard deviation (RMS-SD) and intra/inter-rater reliability of areal BMD acquired at three knee regions using an existing DXA forearm acquisition algorithm; correlation of DXA-based areal BMD with QCT-derived volumetric BMD. Results: The RMS-SD of areal BMD at the distal femoral epiphysis, distal femoral metaphysis and proximal tibial epiphysis averaged 0.021, 0.012 and 0.016 g cm−2, respectively, in acute SCI and 0.018, 0.02 and 0.016 g cm−2 in chronic SCI. All estimates of intra/ inter-rater reliability exceeded 97% and DXA-based areal BMD was significantly correlated with QCT-derived volumetric BMD at all knee regions analyzed. Conclusions: Existing DXA forearm acquisition algorithms are sufficiently precise and reliable for short-term assessments of knee BMD in individuals with SCI. Future work is necessary to quantify the reliability of this approach in longitudinal investigations and to determine its ability to predict fractures and recovery potential. Sponsorship: This work was funded by the Department of Defense, grant number DOD W81XWH-10-1-0951, with partial support from Merck & Co, Inc. Spinal Cord (2014) 52, 821–825; doi:10.1038/sc.2014.122; published online 15 July 2014

ASJC Scopus subject areas

Clinical Neurology
Neurology
Rehabilitation

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title = "Dual energy X-ray absorptiometry of the knee in spinal cord injury: Methodology and correlation with quantitative computed tomography",

abstract = "Study Design: Comparison of diagnostic tests; methodological validation. Objectives: Primary: to investigate the precision and reliability of a knee bone mineral density (BMD) assessment protocol that uses an existing dual energy X-ray absorptiometry (DXA) forearm acquisition algorithm in individuals with spinal cord injury (SCI). Secondary: to correlate DXA-based knee areal BMD with volumetric BMD assessments derived from quantitative computed tomography (QCT). Setting: Academic medical center, Chicago, IL, USA. Methods: Participants: a convenience sample of 12 individuals with acute SCI recruited for an observational study of bone loss and 34 individuals with chronic SCI who were screened for a longitudinal study evaluating interventions to increase BMD. Main outcome measures: root-mean-square standard deviation (RMS-SD) and intrainter-rater reliability of areal BMD acquired at three knee regions using an existing DXA forearm acquisition algorithm; correlation of DXA-based areal BMD with QCT-derived volumetric BMD. Results: The RMS-SD of areal BMD at the distal femoral epiphysis, distal femoral metaphysis and proximal tibial epiphysis averaged 0.021, 0.012 and 0.016 g cm-2, respectively, in acute SCI and 0.018, 0.02 and 0.016 g cm-2 in chronic SCI. All estimates of intra/inter-rater reliability exceeded 97% and DXA-based areal BMD was significantly correlated with QCT-derived volumetric BMD at all knee regions analyzed. Conclusions: Existing DXA forearm acquisition algorithms are sufficiently precise and reliable for short-term assessments of knee BMD in individuals with SCI. Future work is necessary to quantify the reliability of this approach in longitudinal investigations and to determine its ability to predict fractures and recovery potential.",

author = "McPherson, {J. G.} and Edwards, {W. B.} and A. Prasad and Troy, {K. L.} and Griffith, {J. W.} and Schnitzer, {T. J.}",

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AU - McPherson, J. G.

AU - Edwards, W. B.

AU - Prasad, A.

AU - Troy, K. L.

AU - Griffith, J. W.

AU - Schnitzer, T. J.

PY - 2014/11/13

Y1 - 2014/11/13

N2 - Study Design: Comparison of diagnostic tests; methodological validation. Objectives: Primary: to investigate the precision and reliability of a knee bone mineral density (BMD) assessment protocol that uses an existing dual energy X-ray absorptiometry (DXA) forearm acquisition algorithm in individuals with spinal cord injury (SCI). Secondary: to correlate DXA-based knee areal BMD with volumetric BMD assessments derived from quantitative computed tomography (QCT). Setting: Academic medical center, Chicago, IL, USA. Methods: Participants: a convenience sample of 12 individuals with acute SCI recruited for an observational study of bone loss and 34 individuals with chronic SCI who were screened for a longitudinal study evaluating interventions to increase BMD. Main outcome measures: root-mean-square standard deviation (RMS-SD) and intrainter-rater reliability of areal BMD acquired at three knee regions using an existing DXA forearm acquisition algorithm; correlation of DXA-based areal BMD with QCT-derived volumetric BMD. Results: The RMS-SD of areal BMD at the distal femoral epiphysis, distal femoral metaphysis and proximal tibial epiphysis averaged 0.021, 0.012 and 0.016 g cm-2, respectively, in acute SCI and 0.018, 0.02 and 0.016 g cm-2 in chronic SCI. All estimates of intra/inter-rater reliability exceeded 97% and DXA-based areal BMD was significantly correlated with QCT-derived volumetric BMD at all knee regions analyzed. Conclusions: Existing DXA forearm acquisition algorithms are sufficiently precise and reliable for short-term assessments of knee BMD in individuals with SCI. Future work is necessary to quantify the reliability of this approach in longitudinal investigations and to determine its ability to predict fractures and recovery potential.

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Dual energy X-ray absorptiometry of the knee in spinal cord injury: Methodology and correlation with quantitative computed tomography

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