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1

The influence of osteoporotic bone structures of the pelvic-hip complex on stress distribution under impact load

Arkusz K., Klekiel T., Niezgoda T. M., Będziński R.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 1

29--38

EN

Purpose: The aim of this study was to determine the effect of bone mineral density (BMD) on the stress distribution in pelvic-hip complex (PHC) model which included bone structures and soft tissues. Bone mass changes in osteoporosis and osteopenia were considered in this analysis. In addition, the relations between force direction and stress distribution causing PHC fractures were determined. Methods: This paper presents the development and validation of a detailed 3D finite element model with high anatomical fidelity of the PHC and BMD changes in trabecular and cortical bones, modelled based on CT scans. 10 kN loading was induced on a model consisting of 8 ligaments, the pelvis, sacrum, femur in front and side directions. Results: For validation, the results of this model were compared to physiological stress in standing position and previous results with high-energy crashes under side impact load. Analysis of side-impact indicated the influence of BMD on femoral neck fractures, acetabular cartilage and sacroiliac joint delaminations. Front-impact analysis revealed the inferior pubic ramus, femoral neck fractures and soft tissue injuries, i.e., acetabular cartilage and symphysis pubis in osteoporosis and osteopenia. Conclusions: The elaborated PHC model enables effective prediction of pelvis injuries in high-energy trauma, according to Young-Burgess classification, and the determination of the influence of BMD reduction on pelvis trauma depending on force direction. The correlation between BMD and stress distribution causing varying injuries was determined.

2

Relationship between the mineral content of human trabecular bone and selected parameters determined from fatigue test at stepwise-increasing amplitude

Mazurkiewicz A. J., Topoliński T.

Acta of Bioengineering and Biomechanics

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2017

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Vol. 19, no. 3

19--26

EN

Purpose: The study aimed to investigate a relationship between the mineral content of the human trabecular bone and parameters determined from compression fatigue tests at stepwiseincreasing amplitude. Methods: Mineral content of the trabecular bone was estimated as ash density and bone mineral density values. The relationship between the ash density, bone mineral density and factors obtained from fatigue test: fatigue life, cumulative elastic energy and cumulative energy of dissipation was determined. Results: The results from the measurements of ash density and bone mineral density show good correlation with the fatigue test results. The relationship was estimated based on the correlation coefficient R within 0.74-0.79 for the particular pairs of factors. Conclusions: The study shows that the ash density and the bone mineral density are good predictors to estimate the fatigue life of trabecular bone. The study also validates the applicability of the tests at stepwise-increasing amplitude in determining the mechanical properties of trabecular bone.

3

Drilling resistance : A method to investigate bone quality

Lughmani W. A., Farukh F., Bouazza-Marouf K., Ali H.

Acta of Bioengineering and Biomechanics

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2017

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Vol. 19, no. 1

55--62

EN

Purpose: Bone drilling is a major part of orthopaedic surgery performed during the internal fixation of fractured bones. At present, information related to drilling force, drilling torque, rate of drill-bit penetration and drill-bit rotational speed is not available to orthopaedic surgeons, clinicians and researchers as bone drilling is performed manually. Methods: This study demonstrates that bone drilling force data if recorded in-vivo, during the repair of bone fractures, can provide information about the quality of the bone. To understand the variability and anisotropic behaviour of cortical bone tissue, specimens cut from three anatomic positions of pig and bovine were investigated at the same drilling speed and feed rate. Results: The experimental results showed that the drilling force does not only vary from one animal bone to another, but also vary within the same bone due to its changing microstructure. Drilling force does not give a direct indication of bone quality; therefore it has been correlated with screw pull-out force to provide a realistic estimation of the bone quality. A significantly high value of correlation (r 2 = 0.93 for pig bones and r 2 = 0.88 for bovine bones) between maximum drilling force and normalised screw pull-out strength was found. Conclusions: The results show that drilling data can be used to indicate bone quality during orthopaedic surgery.

4

Investigation of microstructure of bone tissue in mandibles of newborn rats after maternal treatment with antiretroviral drugs

Filipek J., Binkowski M., Maciejewska K., Drzazga Z., Wróbel Z.

Biocybernetics and Biomedical Engineering

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2015

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Vol. 35, no. 1

54--63

EN

High-resolution imaging has become a powerful tool for measurements in clinics, laboratory and animal studies, etc. In the present study, we aimed to investigate age related changes in bone development, and the effect of two antiretroviral agents (zidovudine and indinavir), which were administered during pregnancy, on the microstructure and bone mineral density (BMD) in newborn rats (7-, 14- and 28-day-old), with the use of X-ray microcomputed tomography (XMT). Fifty-four mandible bones were collected and divided into 3 groups: group 1 and 2: newborns after maternal treatment of zidovudine and indinavir respectively, group 3: control animals. The specimens were XMT scanned with the resolution of 7 μm and with a density phantom. Histomorphometric parameters and BMD were calculated to assess bone development depending on the administered drug. A statistical analysis was carried out to compare the differences among the control, zidovudine and indinavir groups. The analysis of the microstructure revealed disturbances in the development of the bone tissue in newborn rats. Indinavir seems to have a greater impact on bone microstructure than zidovudine.

5

Comparison of two interpolation methods for empirical mode decomposition based evaluation of radiographic femur bone images

Udhayakumar G., Sujatha C. M., Ramakrishnan S.

Acta of Bioengineering and Biomechanics

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2013

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Vol. 15, no. 2

73--80

EN

Analysis of bone strength in radiographic images is an important component of estimation of bone quality in diseases such as osteoporosis. Conventional radiographic femur bone images are used to analyze its architecture using bi-dimensional empirical mode decomposition method. Surface interpolation of local maxima and minima points of an image is a crucial part of bi-dimensional empirical mode decomposition method and the choice of appropriate interpolation depends on specific structure of the problem. In this work, two interpolation methods of bi-dimensional empirical mode decomposition are analyzed to characterize the trabecular femur bone architecture of radiographic images. The trabecular bone regions of normal and osteoporotic femur bone images (N = 40) recorded under standard condition are used for this study. The compressive and tensile strength regions of the images are delineated using pre-processing procedures. The delineated images are decomposed into their corresponding intrinsic mode functions using interpolation methods such as Radial basis function multiquadratic and hierarchical b-spline techniques. Results show that bi-dimensional empirical mode decomposition analyses using both interpolations are able to represent architectural variations of femur bone radiographic images. As the strength of the bone depends on architectural variation in addition to bone mass, this study seems to be clinically useful.

6

Differences in trabecular bone mechanical strength measured by the x-ray microcomputed tomography and compressive test

Binkowski M., John A., Nowak R., Bożek M., Bielecki M.

Journal of Medical Informatics & Technologies

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2010

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Vol. 15

163--168

EN

The article describes the concept of measurement of the mechanical strength of trabecular bone dissected from human femoral head. When the studies are performed based on the human trabecular bone, there is a risk that correlation can be not achieved due to high discrepancy in the distribution of the bone density and mechanical properties. The compressive tests and X-ray microcomputed tomography with associated density phantom were used to deliver quantitative data. There is a conclusion that the selection of the region in the femoral head has to be performed very carefully. The region where cylinder is dissected can influence the results and produce fake data, which could not be correlated in the density of bone.

7

Thyroid hormone and thyreotropin (TSH) association with densitometric parameters in children

Porwik E., Matusik P., Drzyzdzyk K.

Journal of Medical Informatics & Technologies

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2009

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Vol. 13

141--144

EN

The influence of TSH on bones is still vastly unknown and the information that is known is considered controversial. This important relationship has not been studied in detail. The aim of our research was to assess the correlation between TSH, thyroid hormone and bone mineral density in children measured by DXA scanning. Our study group included 36 children (16 girls and 20 boys) mean age 12.9 š 3.3 years. Basic anthropometrical measurements were performed (height, weight, body mass index-BMI), in all subjects. Blood was collected and measured for TSH and FT4. Bone mineral density of lumbar spine (L2-L4 BMD) and total body (Total Body BMD) were measured by DXA and expressed as bone mineral content (BMC [g]) and bone mineral density (BMD [g/cm2]). BMD Z-Score was also calculated. Correlation between the parameters obtained by DXA and anthropometrical data, TSH and thyroid hormone concentration were calculated. A statistically significant positive correlation was observed between height, weight and BMI and BMD which was calculated. Weight and BMI also had a statically significant correlation with Z-Score and total bone mineral content (BMC – expressed in grams). There was a statistically significant positive correlation between TSH level and Z-Score for both L2-L4 lumbar spine and for total body. TSH did not correlate significantly with BMD [g/cm2] and BMC [g]. FT4 was negatively and significantly correlated with Z-Score for both L2-L4 lumbar spine and for total body. There was also no significant correlation between FT4 and BMD [g/cm2] and BMC [g]. Conclusion: 1. Thyroid stimulating-hormone (TSH) appears to be associated with maintenance of bone mineral density in children. 2. BMD Z-Score especially from L2-L4 lumbar spine assessed by DXA scanning is correlated best with hormonal and biochemical factors potentially influencing bone mineralization in children.

8

Relationships between structure, density and strength of human trabecular bone

Mazurkiewicz A., Topoliński T.

Acta of Bioengineering and Biomechanics

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2009

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Vol. 11, nr 4

55-61

EN

The article deals with the examination of the relationships between density, structure parameters and strength of human trabecular bone. The tests were carried out on the samples taken from osteoporotic and coxarthrotic human femoral heads. The samples cylindrical in shape had the diameters of 10 mm and the height of 8.5 mm. During the tests with uCT scanner the parameters of a sample structure were measured. Bone mineral density (BMD) was measured as well. The samples were subjected to compression in order to assess the ultimate compression strength (fi)c. The relationships between two-element combinations (BMD and one of the structure parameters) and the compression strength of the samples have been studied. The consistence of the results for multiple regression and response surface regression was estimated based on the correlation coefficient R. For the examined pairs of parameters, the value R increased in the range of 7÷30% in comparison with the case where for the strength description only BMD was used. Additionally, the authors' own models of two-variable regression was calculated. The comparison of the results obtained for all models of regression based on the coefficient E proved the consistence of these results.

9

The influence of bone tissue microstructure' parameters on bone mineral density parameter computed within the computer simulation process

Binkowski M., Dyszkiewicz A., Wróbel Z.

Journal of Medical Informatics & Technologies

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2005

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Vol. 9

49--55

EN

The given article was created with reference to lack of correlation between results from densitometry test of bone tissue and its mechanical strength. The changes of bone mechanical strength cannot be solely connected with changes of bone mineral density with micro structural construction of bone tissue. The article describes the research using a computer simulation where changes of physical density and parameters of bone microstructure were modelled. The influences of those parameters for changing the bone mineral density have been computed. It has been calculated during simulation process similar to the way it has been provided from densitometry test. The computation process has been carried out on the basis of computer method of simulation of x-ray radiation propagating through the object and had been was created and tested in the previous research. The model of tested object was defined by spatial high resolution distribution of density. The simulation was executed on a sample of bone tissue. The input data to the model of sample were series of cross-sections obtained previously from micro CT of an animal sample. The changes of parameters were simulated in the model based on a method of 2D image processing. The procedure was used to reduce the trabecular surface for all cross-sections. The results of the algorithm were measured during algorithm process. Images were also analyzed by software to measure parameters of microstructure. It gave a chance to estimate the correlation between measured parameter and parameters of microstructure. The applied method of simulation of attenuation of x-ray radiation allowed to produce densitometry image and to compute parameter similar to bone mineral density. The analysis of obtained results shows how the bone mineral density computed from simulation depends on changes of parameters of microstructure.

10

Simulation of the reaction of X-ray radiation with an object while densitometry tests

Binkowski M., Dyszkiewicz A., Wróbel Z.

Journal of Medical Informatics & Technologies

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2004

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Vol. 8

MM95--104

EN

The computer modelling of absorption effect of X-ray radiation in the bone tissue was analysed. An image, which is produced as a result of X-ray absorption was computed based on the absorption law. The simulation enables to define dimensions and resolution of space where the experiment will be realised. A model of a sample contains information about its geometry and distribution of density. It can be made as simple solids or loaded from external source, like files. This method may be useful to load information about bone microstructure into the simulation space. A source of X-ray radiation was defined as a plate, which has initial radiation intensity. Rules of radiation propagation were simplified to straight model where radiation propagates in the direction perpendicular to the surface of detector which records an image. The image is generated by computation of partial absorption for each space elements. The results of simulation of model of micro-structure of bone tissue are presented. They can be useful to show when densitometry test does not contain accurate and full information about bone tissue. It may by helpful in the future while searching for reasons of incomplete correlation between mineral density and mechanical strength.

11

Analiza tekstur obrazów radiologicznych dla detekcji zmian gęstości mineralnej tkanki kostnej

Cichy P., Materka A., Tuliszkiewicz J.

Elektronika : prace naukowe

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1998

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nr 3

51-63

PL

W artykule przedstawiono zastosowanie cyfrowych technik obróbki i analizy obrazów rentgenowskich do oceny zmian w gęstości mineralnej kości. Rezultaty analizy odniesiono do pomiarów densytometrycznych, wykonanych metodą DXA. Obrazy rentgenograficzne, przedstawiające dalszą część przedramienia, były zarejestrowane z zachowaniem jednakowych warunków technicznych. Dodatkowo w celu ujednolicenia jasności radiogramów zastosowano fantom kalibracyjny. Analizie poddano zarówno obrazy z wyrównaną jasnością fantomu, jak i bez standaryzacji. Zdjęcia rentgenowskie przetworzono na postać cyfrową przy użyciu systemu obrazowego wyposażonego w kamerę CCD. W artykule przedstawiono algorytmy wyznaczania poszczególnych parametrów statystycznych oraz wymiaru fraktainego obrazów cyfrowych. Rozważano wartość oczekiwaną jasności, odchylenie standardowe jasności, skośność histogramu, współczynnik skupienia-kurtozę, energię i entropię oraz wymiary fraktalne estymowane w dziedzinie częstotliwości i metodą wariancyjną. Dlu poszczególnych parametrów wyznaczono ich wartość średnią, odchylenie standardowe oraz współczynnik korelacji liniowej z gęstością tkanki kostnej dystalnego odcinka kości promieniowej. Celem badań byio określenie związków korelacyjnych między parametrami obrazu a wynikami pomiarów densytometrycznych.

EN

Digital image processing and analysis techniques for detection of changes in bone mineral density (BMD) are examined m this paper Analysis results are compared with BMD measured using DXA method. A further part of forearm (Radius UD) is examined. Roentgenogram patterns were registered in the same conditions of exposure and chemical development. Additionally a calibration phantom was used to standardize the results. Radiogram patterns were digitized with a CCD camera. Algorithms for computation of statistical parameters of roentgenogram textures and their fractal dimension are presented. The following texture parameters were computed the mean of intensity, standard deviation of intensity, skewness, kurtosis, energy, entropy and fractal dimension. Fifty radiograms were analyzed. The mean value, standard deviation and coefficient of linear correlation with BMD were estimated for every parameter. Occurrence probability of intensity level is highly correlated with densitometry results. It seems that analysis of fractal dimension can additionally enrich diagnostic knowledge about bone microarchitecture.