Objectives: Bone densitometry is a current method for evaluating skeletal status, assessing osteoporosis, and determining fracture risk DEXA has rapidly become a dominant method for evaluating skeletal status. But the comparison of patient data among different DEXA scanners is complicated because the instruments show differences in scanner design, bone mineral calibration, and analysis algorithms, and scan . site. This study was performed to establish appropriate cross-calibration parameters at the lumbar and femoral sites among two models of DEXA system from different manufacturers.
Materials and Methods: In our study, 63 healthy, Korean women aged 37-81 years(mean age:57.1 ± 7.03) were examined. Posteroanterior Lumbar spine (L2-L4) and hip measurements were obtained on a Hologic QDR 4500, and a Noland XR-36 densitometer. All subjects had no spinal deformities, osteophytes, fractures and scoliosis, bilateral hip replacements, and other conditions that could affect BMD measurements. We performed the measurement of BMD in each subject with different two scanners at two scan sites at the same time.
Results: The correlations of the patients´ spinal BMD(r=0.971) and femoral neck BMD(r=0.905) were excellent for each of the two scanner pairs. From the linear regression analysis-of-the patient data, cross calibration equations for spinal and femoral neck BMD values were derived. The BMD values at the lumbar spine and proximal femur measured using different scanner showed different proportion of diagnostic criteria in osteoporosis.
Conclusion: Even though it has some limitations, the standardization approach as performed in our study may provide compatibility of DEXA results obtained on different scanners
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