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  • 1
    Publication Date: 1983-04-01
    Print ISSN: 0167-5087
    Electronic ISSN: 1872-9606
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Physics
    Published by Elsevier
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  • 2
  • 3
    Publication Date: 2022-01-31
    Description: We assessed the potential of Calcium (Ca) isotope fractionation measurements in blood (δ44/42CaBlood) and urine (δ44/42CaUrine) as a new biomarker for the diagnosis of osteoporosis. One hundred post-menopausal women aged 50 to 75 years underwent dual-energy X-ray absorptiometry (DXA), the gold standard for determination of bone mineral density. After exclusion of women with kidney failure and vitamin D deficiency (〈25 nmol/l) 80 women remained in the study. Of these women 14 fulfilled the standard diagnostic criteria for osteoporosis based on DXA. Both the δ44/42CaBlood (p 〈 0.001) and δ44/42CaUrine (p = 0.004) values were significantly different in women with osteoporosis (δ44/42CaBlood: −0.99 ± 0.10‰, δ 44/42CaUrine: +0.10 ± 0.21‰, (Mean ± one standard deviation (SD) n = 14) from those without osteoporosis (δ44/42CaBlood: −0.84 ± 0.14‰, δ44/42CaUrine: +0.35 ± 0.33‰, (SD), n = 66). This corresponded to the average Ca concentrations in morning spot urine samples ([Ca]Urine) which were higher (p = 0.041) in those women suffering from osteoporosis ([Ca]Urine-Osteoporosis: 2.58 ± 1.26 mmol/l, (SD), n = 14) than in the control group ([Ca]Urine-Control: 1.96 ± 1.39 mmol/l, (SD), n = 66). However, blood Ca concentrations were statistically indistinguishable between groups ([Ca]Blood, control: 2.39 ± 0.10 mmol/l (SD), n = 66); osteoporosis group: 2.43 ± 0.10 mmol/l (SD, n = 14) and were also not correlated to their corresponding Ca isotope compositions. The δ44/42CaBlood and δ44/42CaUrine values correlated significantly (p = 0.004 to p = 0.031) with their corresponding DXA data indicating that both Ca isotope ratios are biomarkers for osteoporosis. Furthermore, Ca isotope ratios were significantly correlated to other clinical parameters ([Ca]Urine, ([Ca]Urine/Creatinine)) and biomarkers (CRP, CTX/P1NP) associated with bone mineralization and demineralization. From regression analysis it can be shown that the δ44/42CaBlood values are the best biomarker for osteoporosis and that no other clinical parameters need to be taken into account in order to improve diagnosis. Cut-off values for discrimination of subjects suffering from osteoporosis were − 0.85‰ and 0.16‰ for δ44/42CaBlood and δ44/42CaUrine, respectively. Corresponding sensitivities were 100% for δ44/42CaBlood and ~79% for δ44/42CaUrine. Apparent specificities were ~55% for δ44/42CaBlood and ~71%. The apparent discrepancy in the number of diagnosed cases is reconciled by the different methodological approaches to diagnose osteoporosis. DXA reflects the bone mass density (BMD) of selected bones only (femur and spine) whereas the Ca isotope biomarker reflects bone Ca loss of the whole skeleton. In addition, the close correlation between Ca isotopes and biomarkers of bone demineralization suggest that early changes in bone demineralization are detected by Ca isotope values, long before radiological changes in BMD can manifest on DXA. Further studies are required to independently confirm that Ca isotope measurement provide a sensitive, non-invasive and radiation-free method for the diagnosis of osteoporosis.
    Type: Article , PeerReviewed
    Format: text
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  • 4
    ISSN: 1432-0827
    Keywords: Key words: Dual-energy X-ray Absorptiometry — Degenerative factors — Postmenopausal women — Bone mineral density — Osteoporosis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. The purpose of this study is to evaluate degenerative factors in a postmenopausal patient group and differentiate the influence on bone mineral density (BMD) measurements by dual-energy X-ray absorptiometry (DXA). The patients and methods included an investigation of 144 postmenopausal women (mean 63.3 years) with PA-DXA of the spine. Degenerative factors (osteophytes, osteochondrosis, scoliosis, and vascular calcification) were evaluated from plain lumbar radiographs, their estimated probability was analyzed as a function of age, and their influence on BMD measured by PA-DXA was determined. The results of the study revealed osteophytes in 45.8%, vascular calcifications in 24.3%, scoliosis in 22.2%, osteochondrosis in 21.5%. The estimated probability for degenerative factors increased from 35 to 80% in the 55- to 70- year age group. Osteophytes and osteochondrosis were associated with up to a 14% increase in BMD values (P 〈 0.001). Vascular calcifications showed a positive trend, whereas scoliosis did not show a discernible influence. We concluded that degenerative factors, except for scoliosis, showed an influence on BMD as measured by DXA. Their prevalence increased rapidly between 55 and 70 years of age. Interpretation of PA-DXA spine data for subjects of or above this age range should be complemented by plain film radiographs.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0827
    Keywords: Quantitative computed tomography ; Dual X-ray absorptiometry ; Degenerative joint disease ; Osteoporosis ; Bone mineral density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract We assessed the impact of various forms of spinal degenerative joint disease (DJD) on bone mineral density (BMD) measured by quantitative computed tomography (QCT) and dual X-ray absorptiometry (DXA) in a group of postmenopausal women. Lateral (T4-L4) and AP (L1-L4) spinal radiographs were reviewed for fracture and DJD in 209 women (mean age 62.6±6.7). The severity of DJD findings was graded as 0,1, or 2 on the lumbar films, except for vertebral osteophytes which were graded from 0 to 3. Vertebral fractures were defined semiquantitatively as approximately 20% reduction in anterior, middle, or posterior vertebral height. BMD was measured in all subjects by QCT and DXA, including posteroanterior DXA (PA-DXA), lateral DXA (L-DXA) and midlateral DXA (mL-DXA). When BMD was measured by QCT and mL-DXA in the 168 women without fractures, no significant differences were found between women with and those without DJD. However, BMD by PA-DXA was significantly higher in women with DJD changes, particularly when osteophytes were present at the vertebral bodies or facet joints. BMD by L-DXA was less affecied by DJD. For this measurement a significant increase in BMD was only noted in subjects with vertebral osteophytes. Multivariate analysis of variance (MANOVA) showed that BMD by QCT and mL-DXA was not affected by DJD. In contrast, for all women, BMD by PA-and L-DXA was affected more by DJD than by fracture status. Chi-square testing demonstrated no significant relationships between vertebral fractures and any of the DJD changes. We conclude that QCT and mL-DXA are superior to PA-DXA and L-DXA in detecting bone loss in patients with DJD. Thus, for these patients, BMD assessment by QCT or mL-DXA may be advisable.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 56 (1995), S. 19-25 
    ISSN: 1432-0827
    Keywords: DXA ; In vivo ; Precision ; Soft tissue
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract In this study we analyzed the effect of variations in bone area size, baseline soft tissue composition represented by the R-value, and bone region of interest positioning on the precision in vivo of bone mineral density (BMD) and content (BMC) as measured by dual X-ray absorptiometry (DXA). The posterior-anterior (PA) spine, decubitus latcral, and femur modes were evaluated. Eleven (PA-spine), 9 (dec-lat), and 14 (femur) postmenopausal women were scanned twice on a Norland XR-26 with repositioning to determine short-term precision of BMD, BMC, AREA, and the R-value. Phantom precisions (CV[%] of 10 consecutive scans) for BMD (BMC) were PA spine: 0.66% (0.57%), neck: 1.1% (1.2%), and trochanter: 0.55% (1.0%). Precisions in vivo (CV[%]; two consecutive scans averaged over all patients) were PA spine: 0.9% (1.0%), dec-lat: 7.1% (18%), neck: 1.3% (1.9%), and trochanter: 2.5% (4.9%). BMD precision could be fully explained by BMC and AREA variations. However, BMC alone was a particularly poor predictor of BMD in the dec-lat (r2=0.05) and in the neck (r2=0.13) modes. AREA was a strong predictor for BMC precision explaining between 41% and 88% of the BMC changes. Changes in soft tissue composition contributed significantly in explaining the BMC changes in the dec-lat projection. A higher dependence of BMC changes on AREA changes resulted in a larger difference between BMC and BMD precision. Thus, particularly in the femur and in the decubitus lateral modes, the use of BMD is advantageous compared with BMC.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0827
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Recent advances in the development of methods to assess the skeleton noninvasively have contributed to screening for risk of osteoporosis, early detection of the disease, and effective monitoring of its progression and response to therapy. The capability now exists to evaluate the peripheral, central, or entire skeleton as well as the trabecular bone or cortical bone envelopes accurately and precisely, with the capacity to determine bone strength and predict fracture risk. In this article we examine the current and future capabilities of quantitative computed tomography (QCT), quantitative ultrasound (QUS), and magnetic resonance microscopy (μMR) to assess architectural and densitometric properties of the skeleton to enhance the prediction of fracture risk.
    Type of Medium: Electronic Resource
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