VALIDATION OF A BONE MINERAL DENSITY CALIBRATION PROTOCOL FOR MICRO-COMPUTED TOMOGRAPHY

2017 ◽  
Vol 17 (01) ◽  
pp. 1750015
Author(s):  
FABIO BARUFFALDI ◽  
ROSSELLA STOICO ◽  
SIMONE TASSANI ◽  
LAURA MECOZZI ◽  
STEFANO FALCIONI ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Bone Mineral Density ◽  
Trabecular Bone ◽  
Bone Mineral ◽  
Bone Structure ◽  
Tissue Type ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Mineral Density ◽  
Calibration Protocol

Micro-computed tomography (micro-CT) is widely used for in vitro studies to characterize bone structure at the resolution of 10–100 microns. However, a densitometric calibration protocol is necessary to convert the X-ray attenuation coefficient provided by micro-CT in bone mineral density (BMD). The lastest one has an important role to improve the accuracy of subject-specific finite element models. This work presents a simple calibration protocol based on the use of solid hydroxyapatite phantoms with the correction of the beam hardening effect. The method was validated in comparison to ashing measures of cortical and trabecular human bone. In addition, bone samples tissue mineral density (TMD) was calculated with two different methods. The correlation between ash density and BMD was linear both for cortical ([Formula: see text]) and trabecular bone ([Formula: see text]). The analysis stratified by tissue type versus the pooled analysis confirmed the validity of a common linear model for both types of tissue ([Formula: see text]). Despite its simplicity, the correlation obtained in this work does not depend on the acquisition settings of the micro-CT. TMD was shown to be dependent on the tissue investigated, with values in the range of 1.15–1.21[Formula: see text]mg/mm3 for trabecular bone, and 1.19–1.29[Formula: see text]mg/mm3 for cortical bone. Results are of some interest for generating micro finite elements models.

scholarly journals Possible role of lymphocytes in glucocorticoid-induced increase in trabecular bone mineral density

2014 ◽  
Vol 224 (1) ◽  
pp. 97-108 ◽  
Author(s):  
Louise Grahnemo ◽  
Caroline Jochems ◽  
Annica Andersson ◽  
Cecilia Engdahl ◽  
Claes Ohlsson ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Bone Mineral Density ◽  
Bone Turnover ◽  
Trabecular Bone ◽  
B Lymphocytes ◽  
Bone Mineral ◽  
Mineral Density ◽  
Trabecular Bone Mineral Density ◽  
Anti Inflammatory ◽  
Lymphocyte Populations

Treatment with anti-inflammatory glucocorticoids is associated with osteoporosis. Many of the treated patients are postmenopausal women, who even without treatment have an increased risk of osteoporosis. Lymphocytes have been shown to play a role in postmenopausal and arthritis-induced osteoporosis, and they are targeted by glucocorticoids. The aim of this study was to investigate the mechanisms behind effects of glucocorticoids on bone during health and menopause, focusing on lymphocytes. Female C57BL/6 or SCID mice were therefore sham-operated or ovariectomized and 2 weeks later treatment with dexamethasone (dex), the nonsteroidal anti-inflammatory drug carprofen, or vehicle was started and continued for 2.5 weeks. At the termination of experiments, femurs were phenotyped using peripheral quantitative computed tomography and high-resolution micro-computed tomography, and markers of bone turnover were analyzed in serum. T and B lymphocyte populations in bone marrow and spleen were analyzed by flow cytometry. Dex-treated C57BL/6 mice had increased trabecular bone mineral density, but lower cortical content and thickness compared with vehicle-treated mice. The dex-treated mice also had lower levels of bone turnover markers and markedly decreased numbers of spleen T and B lymphocytes. In contrast, these effects could not be repeated when mice were treated with the nonsteroidal anti-inflammatory drug carprofen. In addition, dex did not increase trabecular bone in ovariectomized SCID mice lacking functional T and B lymphocytes. In contrast to most literature, the results from this study indicate that treatment with dex increased trabecular bone density, which may indicate that this effect is associated with corticosteroid-induced alterations of the lymphocyte populations.

Dependence of broadband ultrasound attenuation on the elastic anisotropy of trabecular bone

1998 ◽  
Vol 212 (3) ◽  
pp. 223-226 ◽  
Author(s):  
S-M Han ◽  
J-Y Rho
Keyword(s):  
Computed Tomography ◽  
Bone Mineral Density ◽  
Trabecular Bone ◽  
Bone Mineral ◽  
Elastic Anisotropy ◽  
Quantitative Computed Tomography ◽  
Broadband Ultrasound Attenuation ◽  
Mineral Density ◽  
Ultrasound Attenuation ◽  
Ultrasonic Parameters

The effect of trabecular elastic anisotropy on broadband ultrasound attenuation (BUA) and bone mineral density (BMD) was investigated with human and bovine cubic cancellous bones. Ultrasonic parameters describing trabecular anisotropy were found from the three orthogonal ultrasound velocities. BMD was measured using quantitative computed tomography. Three elastic anisotropy ratios were compared to BUA in all three directions and to BMD. The combined effect of anisotropic characteristics and BMD was also correlated with BUA. The results showed that the anisotropy ratios were significantly related to BUA (p<0.05). There was, however, no correlation between BMD and the elastic anisotropy ratios. The combination of BMD and the anisotropy produced a significantly enhanced relationship with BUA.

scholarly journals Three-Dimensional Characterization of Trabecular Bone Mineral Density of the Distal Radius Utilizing Quantitative Computed Tomography

Hand ◽  
2018 ◽  
Vol 15 (1) ◽  
pp. 131-139 ◽  
Author(s):  
Tyler S. Pidgeon ◽  
Katia A. DaSilva ◽  
Joseph J. Crisco ◽  
Eric C. Johnson ◽  
Alison B. Chambers ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Bone Mineral Density ◽  
Trabecular Bone ◽  
Distal Radius ◽  
Bone Mineral ◽  
Quantitative Computed Tomography ◽  
Three Dimensional ◽  
Mineral Density ◽  
Quantitative Ct ◽  
Trabecular Bone Mineral Density

Background: Distal radius (DR) fractures demonstrate patterns of predictable fragments. Bone mineral density (BMD) measurements of these regions of interest (ROIs) may guide more precise treatment. Methods: Computed tomography (CT) scans of the DR of 42 healthy volunteers (23 female) were analyzed using quantitative CT software, measuring BMD within trabecular bone. Seven ROIs were described by alignment with the distal (volar ulnar distal [VUD], dorsal ulnar distal [DUD], volar radial distal [VRD], and dorsal radial distal [DRD]) or proximal (middle ulnar proximal [MUP], middle proximal [MP], and middle radial proximal [MRP]) sigmoid notch. Additional ROIs were the radial styloid (RS) and metadiaphysis (MD). A general estimation equation assessed subject’s BMDs with predictive factors of gender, ROI, and age. The interaction between gender, ROI, and age was included in the model to allow for differences in ROI to vary with gender and/or age. Results: Comparing ROIs within the same gender and, separately, within the same age group revealed significantly higher BMD adjacent to the radioulnar and radiocarpal joints. Male and female individuals aged ≥50 years (mean: 172.7 mg/cm3 ± 6.1) had significantly lower BMD than those aged <50 years (mean: 202.7 mg/cm3 ± 5.8) when all ROIs were considered. Males had higher mean BMD at each ROI compared with females; these differences were significant in 5 of the 9 ROIs: VUD, DUD, DRD, RS, MUP. Conclusions: Trabecular BMD of the DR is highest adjacent to the radioulnar and radiocarpal joints. Female patients and those ≥50 years have lower trabecular BMD.

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