Comparison of Differences in Bone Mineral Density Measurement With 3 Hologic Dual-Energy X-Ray Absorptiometry Scan Modes.

Abstract Introduction Bone mineral density (BMD) measurement using dual-energy X-ray absorptiometry (DXA) is considered a diagnostic parameter for osteoporosis by the World Health Organization (WHO). DXA densitometers have different scanning modes for BMD measurements, although the specific scanning modes vary based upon the manufacturer. For DXA machines manufactured by Hologic, which are used globally, a range of scanning modes exist, including but not limited to (in order of decreasing spatial resolution) Array, Fast Array, and Express Array. Only a handful of prior studies have compared the reproducibility of BMD measurements across scan modes. The present study aimed to add to this body of literature by investigating the differences in BMD measured between three scanning modes in Hologic DXA machines at 19 different health centers. Methodology As part of cross-calibration activities for two multi-center studies in China measuring BMD, the European spine phantom (ESP, 1.000 g/m2) was scanned on 19 different Hologic DXA machines. To measure differences in BMD between the three scan modes most commonly found on the Hologic models available (i.e., Array, Fast Array, Express Array), the ESP measurement was performed 10 times for each scan mode on each Hologic DXA machine. One-sample t-test was used to compare the average difference between the measured ESP results of the three scanning modes at each hospital and reference ESP values. Single factor analysis of variance (ANOVA) was performed to compare the average differences between the pairs of scanning modes using the reference ESP. Results Statistically significant differences between the measured ESP results with reference ESP values were found with each scanning mode at 19 hospitals (all p-values Conclusion The selection of ideal scanning mode requires a balance of scanning time, radiation exposure, and measurement accuracy. In this ex vivo study, the Fast Array scanning mode appeared to be a reasonable choice compared with Array and Express Array for BMD measurements by Hologic DXA. Future in vivo studies can help guide the clinical application of these findings.