Abstract:
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Purpose: Dual-energy x-ray absorptiometry (DXA) systems present
semi-automated analyses of lumbar spine and femur bone mineral density (BMD).
Complete analysis, however, should include a visual assessment by trained
personnel to a) guarantee proper acquisition mode and patient positioning, b)
identify regions of interest (ROI) accurately, and c) identify abnormal
conditions that could artificially elevate BMD. New software known as Computer
Assisted Densitometry (CAD) (GE Medical Systems Lunar) was recently introduced
to identify scans with specific, common irregularities introduced during
acquisition or analysis. Abnormalities include problems related to positioning,
accurate ROI placement, unusual high-density areas, unusual T-scores, and
spinal curvature. We compared the CAD assessment with that of two experienced
DXA users.
Methods and Materials: Seventy-one spine and 70 femur scans were evaluated for
abnormalities in six areas: spine centering, spine alignment, ROI accuracy,
unusual high-density bone, unusual T-scores, and spine curvature. Two-thirds of
the scans exhibited at least one abnormal condition that could be identified by
CAD. Two experienced users with ISCD certification examined the scans and
agreed on their findings prior to knowledge of CAD results. CAD results were
then compared with their visual assessment. Differences between CAD and visual
assessment prompted a secondary review to determine whether a scan abnormality
might have been missed by the densitometry team.
Results: Results showed strong agreement between CAD classification and visual
assessment in all six areas. Experienced users agreed with CAD assessment in
76% to 86% of cases prior to knowing the CAD results. The densitometry team
changed their assessment in 20% to 40% of the cases where there was a
disagreement between CAD and visual assessment. Agreement increased to 83% to
92% after CAD assessment was known. Femur results were similar.
Conclusion: We conclude that CAD provides valuable information for
inexperienced users regarding DXA scan quality and assists experienced
densitometrists in identifying abnormal scans which might have been missed by
visual assessment alone. (E.N.S., D.M.S. received grants from GE Medical
Systems Lunar.)
Faulkner PhD, K,
Computer-assisted Densitometry (CAD): Performance Comparison with Visual Assessment by Experienced Densitometrists. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3105423.html
