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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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Displacement–load curves acquired for four example samples. The curve marked by an asterisk represents the case when the maximal testing device load (20 kN) was achieved and the vertebrae remained unbroken
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Fig2: Displacement–load curves acquired for four example samples. The curve marked by an asterisk represents the case when the maximal testing device load (20 kN) was achieved and the vertebrae remained unbroken

Mentions: Our study was aimed for the assessment of BS (and potentially FR) for patients who did not suffer from vertebrae fractures in the past and not for the fractures diagnosis. The mechanical vertebrae properties are definitely influenced by possible past fractures, so the geometrical measurements and a semi-quantitative method of the vertebrae fracture assessment [22, 23] were used to eliminate the vertebrae suspected for past fractures. Two specimens were excluded as suspected for the previous fractures. Three others were excluded because their displacement–load curves did not allow for the ultimate stress calculations. In these cases, the maximal mechanical testing device load (20 kN) was achieved without vertebrae disruption. An example of such a case is denoted by an asterisk in Fig. 2. In total, 20 specimens were considered.Fig. 2


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)

Displacement–load curves acquired for four example samples. The curve marked by an asterisk represents the case when the maximal testing device load (20 kN) was achieved and the vertebrae remained unbroken
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig2: Displacement–load curves acquired for four example samples. The curve marked by an asterisk represents the case when the maximal testing device load (20 kN) was achieved and the vertebrae remained unbroken
Mentions: Our study was aimed for the assessment of BS (and potentially FR) for patients who did not suffer from vertebrae fractures in the past and not for the fractures diagnosis. The mechanical vertebrae properties are definitely influenced by possible past fractures, so the geometrical measurements and a semi-quantitative method of the vertebrae fracture assessment [22, 23] were used to eliminate the vertebrae suspected for past fractures. Two specimens were excluded as suspected for the previous fractures. Three others were excluded because their displacement–load curves did not allow for the ultimate stress calculations. In these cases, the maximal mechanical testing device load (20 kN) was achieved without vertebrae disruption. An example of such a case is denoted by an asterisk in Fig. 2. In total, 20 specimens were considered.Fig. 2

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