Abstract
Two dual energy X-ray absorptiometric (DXA) instruments have recently become commercially available for local bone densitometry: the QDR-1000 (Hologic Inc.) and the DPX (Lunar Radiation Corp.). We report the precision, influence of femoral rotation, correlation and agreement of bone mineral measurements of the proximal femur by these two instruments. In vitro (femur phantom) short-term precision was 1.1%–3.5%, and the long-term precision was 1.2%–3.8%. In vivo (groups of 10 premenopausal and 10 postmenopausal women) short-term precision of duplicate measurements was 1.6%–4.7%, and long-term precision was 1.9%–5.5%. Overall, the precision for Ward's triangle was over 3% and that for the femoral neck and trochanter, 2%–3%. Rotation of a femur phantom produced a statistically significant change in the bone mineral density (BMD) of the femoral neck. Within a clinically relevant range of femoral rotation (20° inward rotation ±5°) the coefficient of variation (CV%) increased by a mean factor of 1.1–1.4. Although the correlation (r < 0.9) between BMD measurements of the proximal femur by the DPX and QDR-1000 in 30 postmenopausal women was high, there was lack of agreement between the two instruments. We found no statistically significant differences between the right and left femur in 30 postmenopausal women. A bilateral femur scan took a mean total time of about 22 min. We conclude that with the introduction of DXA instruments, the precision of bone mineral measurements of the proximal femur has improved. However, for comparability between commercially available DXA instruments, it might be advantageous if units were standardized.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Alonso CG, Lopez JBD, Virges MJ, Serrano M, Carcedo MAG, Cannata JB (1990) Assessing on a long-term basis the precision error of dual energy radiography absorptiometry. In: Christiansen C, Overgaard K (eds) Osteoporosis 1990. Proceedings of the third international symposium on osteoporosis, Oct. 14–20, 1990, Copenhagen, Denmark, pp 883–884
Bland JM, Altman DG (1986) Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 11:307–310
Glüer CC, Steiger PT, Selvidge R, Elliesen-Kliefoth K, Hayashi C, Geneat HK (1990) Comparative assessment of dual-photon absorptiometry and dual-energy radiography. Radiology 174:223–228
Gundry CR, Miller CW, Ramos E, Moscona A, Stein JA, Mazess RB, Sartoris DJ, Resnick D (1990) Dual-energy radiographic absorptiometry of the lumbar spine: clinical experience with two different systems. Radiology 174:539–541
Hansen MA, Hassager C, Overgaard K, Marslew U, Riis BJ, Christiansen C (1990) Dual-energy X-ray absorptiometry: a precise method of measuring bone mineral density in the lumbar spine. J Nucl Med 31:1156–1162
Hassager C, Gotfredsen A, Jensen SB, Christiansen C (1991) The impact of measurement errors on the diagnostic value of bone mass measurements. Theoretical consideration. Osteoporosis Int (in press)
Kelly TL, Slovik DM, Schoenfeld DA, Neer RM (1988) Quantitative digital radiography versus dual photon absorptiometry of the lumbar spine. J Clin Endocrinol Metab 67:839–844
Mazess RB, Hanson J, Sorenson J, Barden HS (1988) Accuracy and precision of dual-photon absorptiometry. In: Dequecker J, Geusens P, Wahner H (eds) Bone mineral measurements by photon absorptiometry: methodological problems. Leuven University Press, Leuven, pp 157–164
Mazess R, Collick B, Trempe J, Barden H, Hanson J (1989) Performance evaluation of dual-energy X-ray bone densitometer. Calcif Tissue Int 44:228–232
Nijs J, Geusens P, Dumortier F, Borghs H, Decqueker J (1990) Comparison of DEXA and DPA in clinical situations. In: Christiansen C, Overgaard K (eds) Osteoporosis 1990. Proceedings of the third international symposium on osteoporosis, Oct. 14–20, 1990, Copenhagen, Denmark, pp 726–727
Nilas L, Hassager C, Christiansen C (1988) Long-term precision of dual photon absorptiometry in the spine in clinical settings. Bone Mineral 3:305–315
SAS Institute Inc (1987) SAS/STAT guide for personal computers, version 6 edn. SAS Institute Inc., Cary, p 551
Slosman DO, Rizzoli R, Buchs B, Piana F, Donath A, Bonjour J-P (1990) Comparative study of performances of X-ray and gadolinium 153 bone densitometers at the level of the spine, femoral neck and femoral shaft. Eur J Nucl Med 17:3–9
Sorenson JA, Duke PR, Smith SW (1989) Simulation studies of dual energy X-ray absorptiometry. Med Phys 16:75–80
Strause L, Braecker M, Saltman P, Sartoris D, Kerr E (1989) A comparison of quantative dual-energy radiographic absorptiometry and dual photon absorptiometry of the lumbar spine in postmenopausal women. Calcif Tissue Int 45:288–291
Wahner HW, Dunn WL, Brown ML, Morin RL, Riggs BL (1988a) Comparison of dual-energy X-ray absorptiometry and dual photon absorptiometry for bone mineral measurements of the lumbar spine. Mayo Clin Proc 63:1075–1084
Wahner HW, Dunn WL, Dimagno M, Machler D (1988b) Bone mineral (BM) measurements at the hip by dual photon absorptiometry (DPA), precision and performance evaluation. In: Dequecker J, Geusens P, Wahner H (eds) Bone mineral measurements by photon absorptiometry: methodological problems. Leuven University Press, Leuven, pp 179–189
Wilson CR, Collier BD, Carrere GF, Jacobson DR (1990) Acronym for dual-energy X-ray absorptiometry. Radiology 176:875–876
Wilson CR, Gogelman I, Blake GM, Rodin A (1991) The effects of positioning on dual energy X-ray bone densitometry of the proximal femur. Bone Mineral 13:69–76
Author information
Authors and Affiliations
Additional information
Offprint requests to: O.L. Svendsen
Rights and permissions
About this article
Cite this article
Svendsen, O.L., Marslew, U., Hassager, C. et al. Measurements of bone mineral density of the proximal femur by two commercially available dual energy X-ray absorptiometric systems. Eur J Nucl Med 19, 41–46 (1992). https://doi.org/10.1007/BF00178307
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00178307