Improved precision with Hologic Apex software

Abstract

Summary: The precision of Hologic Apex v2.0 analysis software is significantly improved from Hologic Delphi v11.2 software and is comparable to GE Lunar Prodigy v7.5 software. Apex and Delphi precisions were, respectively, 1.0% vs. 1.2% (L1-L4 spine), 1.l % vs. 1.3% (total femur), 1.6% vs. 1.9% (femoral neck), and 0.7% vs. 0.9% (dual total femur). Introduction: Precision of bone mineral density (BMD) measurements by dual-energy X-ray absorptiometry (DXA) is known to vary by manufacturer, model, and technologist. This study evaluated the precision of three analysis versions: Apex v2.0 and Delphi v11.2 (Hologic, Inc.), and Prodigy v7.5 (GE Healthcare, Inc.) independent of technologist skill. Methods: Duplicate spine and dual hip scans on 90 women were acquired on both Delphi and Prodigy DXA systems at three clinics. BMD measures were converted to standardized BMD (sBMD) units. Precision errors were described as a root-mean-square (RMS) standard deviations and RMS percent coefficients of variation across the population. Results: Apex and Delphi values were highly correlated (r ranged from 0.90 to 0.99). Excluding the right neck, the Apex precision error was found to be 20% to 25% lower than the Delphi (spine: 1.0% versus 1.2% (p<0.05), total hip: 1.1% versus 1.3% (p<0.05), right neck: 2.3% versus 2.6% (p>0.1)). No statistically significant differences were found in the precision error of the Apex and Prodigy (p>0.05) except for the right neck (2.3% versus 1.8% respectively, p=0.03). Conclusion: The Apex software has significantly lower precision error compared to Delphi software with similar mean values, and similar precision to that of the Prodigy. © 2008 International Osteoporosis Foundation and National Osteoporosis Foundation.