Hologic Total Hip Region of Interest Placed Too High

Case Description:

In the analysis on the left, the bottom of the total hip region of interest box is not 10 pixels below the bottom of the lesser trochanter, it is at the bottom of the lesser trochanter. In the analysis on the right, the bottom of the region of interest box is down 10 pixels from the bottom of the lesser trochanter.  In this case, the bone mineral density is higher at the total hip because more cortical bone is included.  It is recommended that a technologist step through the analysis each time.  Auto-analysis is said to be correct <50% of the time.

In the analysis protocol in Hologic the upper, inner, and outer edges are set with a blue line that touches bone and there is a yellow line that is 5 pixels out.  For the bottom line, the blue line touches the bottom of the lesser trochanter and the yellow line is 10 pixels below the lesser trochanter.

Credit:

Sarah L Morgan, MD, RD, CCD, The University of Alabama at Biringham

References:

• Feit, A., et al., Effect of positioning of the region of interest on bone density of the hip. . J Clin Densitom, 2020: 23(3) p 426-431.
• Morgan, S.L. and F. Peace, Do changes in the femoral neck box size make a significant difference in femoral neck BMD? . J Clin Densitom, 2011. 14 p. 156
• McKiernan, F.E., et al., A long femur scan field does not alter proximal femur bone mineral density measurements by dual-energy X-ray absorptiometry. J Clin Densitom, 2011. 14(3): p. 354-8.
• Prater, G.L., et al., The effect of extending femur scan length on BMD results on the Hologic Discovery-W scanner. J Clin Densitom, 2014. 17(4): p. 518-21.
• Celik, O., et al., The effect of hip rotation on bone mineral density of the proximal femur measured by dual energy X-ray absorptiometry. Eklem Hastalik Cerrahisi, 2009. 20(2): p. 71-7.
• Cheng, X.G., et al., Effects of anteversion on femoral bone mineral density and geometry measured by dual energy X-ray absorptiometry: a cadaver study. Bone, 1997. 21(1): p. 113-7.
• Girard, M.S., et al., Measured femoral density by dual-energy X-ray absorptiometry as a function of rotation. Orthop Rev, 1994. 23(1): p. 38-40.
• Goh, J.C., S.L. Low, and K. Bose, Effect of femoral rotation on bone mineral density measurements with dual energy X-ray absorptiometry. Calcif Tissue Int, 1995. 57(5): p. 340-3.
• Lekamwasam, S. and R.S. Lenora, Effect of leg rotation on hip bone mineral density measurements. J Clin Densitom, 2003. 6(4): p. 331-6.
• Rosenthall, L., Range of change of measured BMD in the femoral neck and total hip with rotation in women. J Bone Miner Metab, 2004. 22(5): p. 496-9.
• Tang, H., S.M. Ren, and X.Z. Luo, [Effect of femoral rotation on hip bone mineral density measurement]. Zhongguo Yi Xue Ke Xue Yuan Xue Bao, 2003. 25(3): p. 267-70.
• Wilson, C.R., et al., The effect of positioning on dual energy X-ray bone densitometry of the proximal femur. Bone Miner, 1991. 13(1): p. 69-76.
• McKiernan, F. and W. Washington, Effect of subtle positioning flaws on measured bone mineral density of the hip. J Clin Densitom, 2005. 8(3): p. 330-4.
• Hans, D., et al., Effects of a new positioner on the precision of hip bone mineral density measurements. J Bone Miner Res, 1997. 12(8): p. 1289-94.