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  • Articles: DFG German National Licenses  (3)
  • Osteoporosis  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Broadband ultrasound attenuation signals depend on trabecular orientation: An in vitro study (1993)
    Springer
    Osteoporosis international 3 (1993), S. 185-191 
    Details
    ISSN: 1433-2965
    Keywords: Bone densitometry ; Bone structure ; Osteoporosis ; Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Quantitative ultrasound (QUS) techniques have recently been introduced as alternative methods free of ionizing radiation for non-invasive assessment of skeletal status in osteoporosis. We carried out an in vitro study on bone specimens to investigate whether broadband ultrasound attenuation (BUA) signals are associated with bone structure, specifically with the orientation of the trabeculae, and whether this association is independent of the association between orientation and bone mineral density (BMD) as measured by dual-energy X-ray absorptiometry (DXA). BUA and BMD of 10 cubical specimens of purely trabecular bovine bone were examined along the three principal axes. The relative orientation of the trabeculae with respect to the direction of the ultrasound beam was evaluated on high-resolution conventional radiographs employing a semiquantitative ALIGNMENT score ranging from −2 (for perpendicular) to +2 (parallel). BUA variability was 27.6 dB/MHz, reflecting both inter-specimen (18.2 dB/MHz) and intra-specimen (19.4 dB/MHz) variability at comparable levels and to a much lesser extent reproducibility errors (1 dB/MHz). BUA was 44%–54% larger along the axis of the compressive trabeculae as compared with the two perpendicular axes. BMD and ALIGNMENT showed independent significant associations with BUA. A change in ALIGNMENT from perpendicular to parallel corresponded to a difference in BUA of 36.1 dB/MHz. The substantial level of intra-specimen variability suggests that BUA reflects anisotropical characteristics of trabecular bone. The association of BUA and ALIGNMENT indicates that BUA signals depend on trabecular orientation. This association is independent of BMD, indicating that BUA has considerable potential for non-invasive assessment of bone structure and strength, free of ionizing radiation, and for complementing existing bone densitometry examinations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01623674
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Comparison of semiquantitative and quantitative techniques for the assessment of prevalent and incident vertebral fractures (1995)
    Springer
    Osteoporosis international 5 (1995), S. 354-370 
    Details
    ISSN: 1433-2965
    Keywords: Morphometry ; Osteoporosis ; Semiquantitative assessment ; Vertebral
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To compare visual semiquantitative (SQ) reading and quantitative morphometry (QM) for assessing prevalent and incident vertebral fractures, radiographs of the thoracolumbar spine were evaluated in 400 (only baseline films) and 335 (baseline and follow-up films) postmenopausal women with osteopenia as defined by aT-score of less than 2 SD below young normals. QM was performed using different cutoff thresholds, and the SQ reading was performed by three radiologists independently. A joint consensus reading of the radiographs by all participating radiologists was used as a reference standard. Our results indicate that the concordance within SQ methods is excellent, and it is higher than that between SQ and QM regardless of the cutoff criteria used. This finding was consistent for the diagnosis of prevalent as well as incident vertebral fractures. For prevalent fractures the use of the 2.5 SD cutoff criterion provided the highest concordance with the consensus reading and with the radiologists' reading, thereby providing high sensitivity (70.23%) with moderate specificity (98.76%) relative to the consensus reading when compared with the 3 SD or 4 SD cutoff criteria. For the diagnosis of incident vertebral fractures the best agreement between our consensus reading and QM was found for an absolute reduction of 6 mm and for a combination of relative and absolute reduction of 15% and 3 mm in vertebral height. The respective sensitivities and specificities for the two criteria were 51%/99.9% and 75.4%/98.9%, respectively. Even though the consensus reading may favor the reader's evaluation over QM, the assessment of prevalent and incident fractures using QM alone may not be sufficiently reliable for detection of vertebral fractures in epidemiological studies and clinical trials. It should be performed principally in conjunction with a trained radiologist or a highly experienced clinician.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01622258
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Three quantitative ultrasound parameters reflect bone structure (1994)
    Springer
    Calcified tissue international 55 (1994), S. 46-52 
    Details
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Ultrasound ; Bone densitometry ; Bone structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract We investigated whether quantitative ultrasound (QUS) parameters are associated with bone structure. In an in vitro study on 20 cubes of trabecular bone, we measured broadband ultrasound attenuation (BUA) and two newly defined parameters—ultrasound velocity through bone (UVB) and ultrasound attenuation in bone (UAB). Bone mineral density (BMD) was measured by dual X-ray absorptiometry (DXA) and bone structure was assessed by microcomputed tomography (μCT) with approximately 80 μm spatial resolution. We found all three QUS parameters to be significantly associated with bone structure independently of BMD. UVB was largely influenced by trabecular separation, UAB by connectivity, and BUA by a combination of both. For a one standard deviation (SD) increase in UVB, a decrease in trabecular separation of 1.2 SD was required compared with a 1.4 SD increase in BMD for the same effect. A 1.0 SD increase in UAB required a reduction in connectivity of 1.4 SD. Multivariate models of QUS versus BMD combined with bone structure parameters showed squared correlation coefficients of r2=0.70–0.85 for UVB, r2=0.27–0.56 for UAB, and r2=0.30–0.68 for BUA compared with r2=0.18–0.58 for UVB, r2〈0.26 for UAB and r2〈0.13 for BUA for models including BMD alone. QUS thus reflects bone structure, and a combined analysis of QUS and BMD will allow for a more comprehensive assessment of skeletal status than either method alone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310168
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    Paper (German National Licenses)
    Fulltext
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