Accurate assessment of precision errors: How to measure the reproducibility of bone densitometry techniques
Rent the article at a discountRent now
* Final gross prices may vary according to local VAT.Get Access
Assessment of precision errors in bone mineral densitometry is important for characterization of a technique's ability to detect logitudinal skeletal changes. Short-term and long-term precision errors should be calculated as root-mean-square (RMS) averages of standard deviations of repeated measurements (SD) and standard errors of the estimate of changes in bone density with time (SEE), respectively. Inadequate adjustment for degrees of freedom and use of arithmetic means instead of RMS averages may cause underestimation of true imprecision by up to 41% and 25% (for duplicate measurements), respectively. Calculation of confidence intervals of precision errors based on the number of repeated measurements and the number of subjects assessed serves to characterize limitations of precision error assessments. Provided that precision error are comparable across subjects, examinations with a total of 27 degrees of freedom result in an upper 90% confidence limit of +30% of the mean precision error, a level considered sufficient for characterizing technique imprecision. We recommend three (or four) repeated measurements per individual in a subject group of at least 14 individuals to characterize short-term (or long-term) precision of a technique.
- Nilas L, Christiansen CC. Rates of bone loss in normal women: evidence of accelerated trabecular bone loss after the menopause. Eur J Clin Invest 1988;18:529–34.
- Block J, Smith R, Glüer CC, et al. Models of spinal trabecular bone loss as determined by quantitative computed tomography. J Bone Miner Res 1989;4:249–57.
- Kalender WA, Felsenberg D. Louis O, et al. Reference values for trabecular and cortical vertebral bone density in single and dual-energy quantitative computed tomography. Eur J Radiol 1989;9:75–80.
- Harris S, Dawson-Hughes B. Rates of change in bone mineral density of the spine, heel, femoral neck, and radius in healthy postmenopausal women. Bone Miner 1992;17:87–95.
- Davis JW, Ross PD, Wasnich RD, MacLean CJ, Vogel JM. Long-term precision of bone loss rate measurements among postmenopausal women. Calcif Tissue Int 1991;48:311–8.
- Pacifici R, Rupich R, Vered I, et al. Dual energy radiography (DER): a preliminary comparative study. Calcif Tissue Int 1988;43:189–91.
- Glüer CC, Steiger P, Selvidge R, et al. Comparative assessment of dual-photon-absorptiometry and dual-energy-radiography. Radiology 1990;174:223–8.
- Steiger P, Block JE, Steiger S, et al. Spinal bone mineral density by quantitative computed tomography: effect of region of interest, vertebral level, and technique. Radiology 1990;175:537–43.
- Lilley J, Walters BG, Heath DA, Drolc Z. In vivo and in vitro precision of bone density measured by dual-energy x-ray absorption. Osteoporosis Int 1991;1:141–6.
- Schneider P, Börner W, Mazess RB, Barden H. The relationship of peripheral to axial bone density. Bone Miner 1988;4:279–87.
- Rüegsegger P, Durand E, Dambacher MA. Localization of regional forearm bone loss from high resolution computed tomo-graphic images. Osteoporosis Int 1991;1:6–80.
- Glüer CC, Vahlensieck M, Faulkner KG, et al. Site-matched calcaneal measurements of broadband ultrasound attenuation and single x-ray absorptiometry: do they measure different skeletal properties? J Bone Miner Res 1992;7:1071–9.
- Devogelaer JP, Baudoux C, Nagant de Deuxchaisnes C. Reproducibility BMD measurements on the QDR-2000 Hologic, Inc. In: Proceedings of Ninth International Workshop on Bone Densitometry, Traverse City, USA, 1992.
- Kotz S, Johnson NL, Encyclopedia of statistical sciences. Vol. 8, New York: Wiley, 1982.
- Harnett DL. Statistical methods. Reading, MA: Addison-Wesley, 1982.
- Kuzma JW. Basic statistics for the health sciences. Mountain View, CA: Mayfield, 1984.
- Olson CL. Statistics: Making sense of data. Boston, Mass.: Allyn and Bacon, 1987.
- Wonnacott TH, Wonnacott RJ. Introductory statistics for business and economics. New York: Wiley, 1984.
- Ryan PJ, Blake GM, Herd R, Parker J, Fogelman I. Spine and femur BMD by DXA in patients with varying severity spinal osteoporosis. Calcif Tissue Int 1993;52:263–8.
- Abramowitz M, Stegun IA, Handbook of mathematical functions. Washington, DC: National Bureau of Standards, 1964.
- Accurate assessment of precision errors: How to measure the reproducibility of bone densitometry techniques
Volume 5, Issue 4 , pp 262-270
- Cover Date
- Print ISSN
- Online ISSN
- Additional Links
- Bone densitometry
- Precision error
- Industry Sectors