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  • Bone remodeling  (1)
  • Key words:High-resolution computed tomography – Histomorphometry – Human cancellous bone – Mechanical properties  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 35 (1983), S. 410-417 
    ISSN: 1432-0827
    Keywords: Bone remodeling ; Histomorphometry ; Corticosteroid therapy ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have compared the mean wall thickness (MWT) and active formation periods (sigmaf(A)) of trabecular bone packets in iliac crest biopsies from 20 patients (7 male, 13 female) with corticosteroid-induced osteoporosis (CS-OP) and 20 age- and sex-matched controls. The trabecular bone volume (TBV) of the CS-OP patients (9.6%±2.2% [SD]) was significantly reduced compared to controls (19.3%±5.1%). The MWT of CS-OP patients (32.7±4.3 µm) was also significantly lower than the control value (48.0±6.2 µm). There was a positive correlation between MWT and TBV in both groups. The mineralization rate (M) of the CS-OP patients (0.54±0.25 µm/day) was within the normal range, and since there was no increase in osteoid seam thickness, so therefore was the osteoblastic appositional rate (OAR). The active formation period of trabecular bone packets (sigmaf(A)=MWT/M) was significantly lower in the CS-OP patients (55.9 ± 14.4 days) than in the control group (68.1 ± 9.4 days). MWT and sigmaf(A) both decreased with age in the control group, whereas in the CS-OP group they were independent of age. We conclude that corticosteroid therapy results in a reduction of the MWT of trabecular bone packets and, consequently, of TBV. In these patients, where the OAR was normal, the reduction in MWT was apparently caused by a shortening of the lifespan of the active osteoblastic population at the basic multicellular unit (BMU) level.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1433-2965
    Keywords: Key words:High-resolution computed tomography – Histomorphometry – Human cancellous bone – Mechanical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: The aim of the present study on human vertebral cancellous bone was to validate structural parameters measured with high-resolution (150 μm) computed tomography (HRCT) by referring to histomorphometry and to try to predict mechanical properties of bone using HRCT. Two adjacent vertical cores were removed from the central part of human L2 vertebral body taken after necropsy in 22 subjects aged 47–95 years (10 women, 12 men; mean age 79 ± 14 years). The right core was used for structural analysis performed by both HRCT and histomorphometry. Two cancellous bone specimens were extracted from the left core: a cube for HRCT and a compression test, and a cylinder for a shear test. Significant correlations were found between HRCT and histomorphometric measurements (BV/TV, trabecular thickness, separation and number, and node-strut analysis), but with higher values for most of the tomographic parameters (BV/TV and trabecular thickness determined by HRCT were overestimated by a factor 3.5 and 2.5 respectively, as compared with histomorphometry). The maximum compressive strength and Young’s modulus were highly correlated (ρ= 0.99, p〈0.0005). Significant correlation was obtained between bone mineral density (determined using dual-energy X-ray absorptiometry) and the maximum compressive strength (ρ= 0.64, p= 0.002). In addition the maximum compressive strength and architectural parameters determined by HRCT or histomorphometry showed significant correlations (e.g., for HRCT, BV/TV: ρ = 0.88, p〈0.0005, N.Nd/TV: ρ= 0.73, p〈0.001). The shear strength was significantly correlated with BV/TV (ρ= 0.62, p= 0.002), Tb.Sp (ρ=−0.58, p= 0.004) and TSL (ρ= 0.55, p= 0.006) measured by HRCT. In conclusion, an HRCT system with 150 μm resolution is not sufficient to predict the true values of the structural parameters measured by histomorphometry, although high correlations were found between the two methods. However, we showed that a resolution of 150 μm allowed us to predict the mechanical properties of human cancellous bone. In vivo peripheral systems with such a resolution should be of interest and would deliver an acceptable radiation dose to the patient.
    Type of Medium: Electronic Resource
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