Article

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.

Langue : ANGLAIS