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Combining areal DXA bone mineral density and vertebrae postero-anterior width improves the prediction of vertebral strength.

Tatoń G, Rokita E, Wróbel A, Korkosz M - Skeletal Radiol. (2013)

Bottom Line: The coefficients of correlation between P(max) and vBMD(min), vBMD(av), as well as BMAD, were r = 0.626 (p = 0.005), r = 0.610 (p = 0.006) and r = 0.567 (p = 0.012), respectively.Our results showed that aBMD normalized by vertebrae dimensions describes vertebrae BS better than aBMD alone.The considered indices vBMD(av), vBMD(min), and BMAD can be measured in routine PA DXA and considerably improve BS variability prediction. vBMD(min) is superior compared to vBMD(av) and BMAD.

View Article: PubMed Central - PubMed

Affiliation: Department of Biophysics, Jagiellonian University Medical College, Łazarza 16, 31530, Kraków, Poland, g.taton@uj.edu.pl.

ABSTRACT

Objective: Areal bone mineral density (aBMD) measured by dual-energy X-ray absorptiometry (DXA) is an important determinant of bone strength (BS), despite the fact that the correlation between aBMD and BS is relatively weak. Parameters that describe BS more accurately are desired. The aim of this study was to determine whether the geometrical corrections applied to aBMD would improve its ability for BS prediction. We considered new parameters, estimated from a single DXA measurement, as well as BMAD (bone mineral apparent density) reported in the literature.

Materials and methods: In vitro studies were performed with the L3 vertebrae from 20 cadavers, which were studied with DXA and quantitative computed tomography (QCT). A mechanical strength assessment was carried out. Two new parameters were introduced: vBMD(min) = aBMD/W(PA)(min) and vBMD(av) = aBMD/W(PA)(av) (W PA(min) -minimal vertebral body width in postero-anterior (PA) view, W(PA)(av) - average PA vertebral body width). Volumetric BMD measured by QCT (vBMD), aBMD, BMAD, vBMD(min), and vBMD(av) were correlated to ultimate load and ultimate stress (P(max)) to find the best predictor of vertebrae BS.

Results: The coefficients of correlation between P(max) and vBMD(min), vBMD(av), as well as BMAD, were r = 0.626 (p = 0.005), r = 0.610 (p = 0.006) and r = 0.567 (p = 0.012), respectively. Coefficients for vBMD and aBMD are r = 0.648 (p = 0.003) and r = 0.511 (p = 0.03), respectively.

Conclusions: Our results showed that aBMD normalized by vertebrae dimensions describes vertebrae BS better than aBMD alone. The considered indices vBMD(av), vBMD(min), and BMAD can be measured in routine PA DXA and considerably improve BS variability prediction. vBMD(min) is superior compared to vBMD(av) and BMAD.

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Schematic view of DXA vertebral measurement geometry. The vertebra is scanned in the postero-anterior view. For mathematical description used in the present work, the whole vertebrae body was divided into N long and narrow pieces. The base area of each element is a, while their length is different for every element (denoted as wi). The whole vertebrae body projection area is A
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Fig1: Schematic view of DXA vertebral measurement geometry. The vertebra is scanned in the postero-anterior view. For mathematical description used in the present work, the whole vertebrae body was divided into N long and narrow pieces. The base area of each element is a, while their length is different for every element (denoted as wi). The whole vertebrae body projection area is A

Mentions: All symbols used are presented in Table 1 and Fig. 1. Threeis a simplified scheme of the vertebrae DXA measurement geometry presented in Fig. 1. In order to deliver appropriate formulas, the whole vertebral volume was divided into N small volume elements. The base area of each volume element is small and equal to a. The areal bone mineral density (aBMD) is defined as:Table 1


Combining areal DXA bone mineral density and vertebrae postero-anterior width improves the prediction of vertebral strength.

Tatoń G, Rokita E, Wróbel A, Korkosz M - Skeletal Radiol. (2013)

Schematic view of DXA vertebral measurement geometry. The vertebra is scanned in the postero-anterior view. For mathematical description used in the present work, the whole vertebrae body was divided into N long and narrow pieces. The base area of each element is a, while their length is different for every element (denoted as wi). The whole vertebrae body projection area is A
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3824230&req=5

Fig1: Schematic view of DXA vertebral measurement geometry. The vertebra is scanned in the postero-anterior view. For mathematical description used in the present work, the whole vertebrae body was divided into N long and narrow pieces. The base area of each element is a, while their length is different for every element (denoted as wi). The whole vertebrae body projection area is A
Mentions: All symbols used are presented in Table 1 and Fig. 1. Threeis a simplified scheme of the vertebrae DXA measurement geometry presented in Fig. 1. In order to deliver appropriate formulas, the whole vertebral volume was divided into N small volume elements. The base area of each volume element is small and equal to a. The areal bone mineral density (aBMD) is defined as:Table 1

Bottom Line: The coefficients of correlation between P(max) and vBMD(min), vBMD(av), as well as BMAD, were r = 0.626 (p = 0.005), r = 0.610 (p = 0.006) and r = 0.567 (p = 0.012), respectively.Our results showed that aBMD normalized by vertebrae dimensions describes vertebrae BS better than aBMD alone.The considered indices vBMD(av), vBMD(min), and BMAD can be measured in routine PA DXA and considerably improve BS variability prediction. vBMD(min) is superior compared to vBMD(av) and BMAD.

View Article: PubMed Central - PubMed

Affiliation: Department of Biophysics, Jagiellonian University Medical College, Łazarza 16, 31530, Kraków, Poland, g.taton@uj.edu.pl.

ABSTRACT

Objective: Areal bone mineral density (aBMD) measured by dual-energy X-ray absorptiometry (DXA) is an important determinant of bone strength (BS), despite the fact that the correlation between aBMD and BS is relatively weak. Parameters that describe BS more accurately are desired. The aim of this study was to determine whether the geometrical corrections applied to aBMD would improve its ability for BS prediction. We considered new parameters, estimated from a single DXA measurement, as well as BMAD (bone mineral apparent density) reported in the literature.

Materials and methods: In vitro studies were performed with the L3 vertebrae from 20 cadavers, which were studied with DXA and quantitative computed tomography (QCT). A mechanical strength assessment was carried out. Two new parameters were introduced: vBMD(min) = aBMD/W(PA)(min) and vBMD(av) = aBMD/W(PA)(av) (W PA(min) -minimal vertebral body width in postero-anterior (PA) view, W(PA)(av) - average PA vertebral body width). Volumetric BMD measured by QCT (vBMD), aBMD, BMAD, vBMD(min), and vBMD(av) were correlated to ultimate load and ultimate stress (P(max)) to find the best predictor of vertebrae BS.

Results: The coefficients of correlation between P(max) and vBMD(min), vBMD(av), as well as BMAD, were r = 0.626 (p = 0.005), r = 0.610 (p = 0.006) and r = 0.567 (p = 0.012), respectively. Coefficients for vBMD and aBMD are r = 0.648 (p = 0.003) and r = 0.511 (p = 0.03), respectively.

Conclusions: Our results showed that aBMD normalized by vertebrae dimensions describes vertebrae BS better than aBMD alone. The considered indices vBMD(av), vBMD(min), and BMAD can be measured in routine PA DXA and considerably improve BS variability prediction. vBMD(min) is superior compared to vBMD(av) and BMAD.

Show MeSH