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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.

2

Modeling of X-ray propagation in bone microstructure

Binkowski M., Król Z., Wróbel Z., Zeilhofer H.-F.

Journal of Medical Informatics & Technologies

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2005

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Vol. 9

75--82

EN

This paper presents some results concerning the analysis of X-ray propagation through biological structures. We introduce a physical model of the phenomenon and a numerical method based on this model for simulation of X-ray radiation propagation. The proposed method enables generation of radiological projections like those in the computed tomography or microtomography. We have focused our attention on the attenuation of X-ray radiation in bone tissue. Our computational model enables simulation of radiation propagation in the virtual specimen. The virtual bone microstructures used in our experiments are derived from the microtomography datasets of real bone specimens. The main advantage of our approach is that we can change the microstructure of the virtual sample in many ways by using the image processing methods. Results presented in this paper contain simulations of X-ray propagation for modified and unmodified trabecular microstructures as well as the visualization of the radiation intensity distribution for the simulated cases. With this new simulation technique, it is possible for example to analyze the propagation of X-ray radiation for different pathologic types of bone microstructure (e.g. virtually generated osteoporosis).

3

Trabecular bone microstructure analysis of first metacarpal bone; correlation’s with bone mineral density of spine

Chaberek S.

Journal of Medical Informatics & Technologies

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2000

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Vol. 1

BI 91--99

EN

The aim of this study was presented parameters of bone microstructure the method was based on the 2 dimensional FFT analysis, fractal dimension and analysis distribution histogram of intensity microradiographic image of trabecular bone microstructure. We compare all parameters with BMD using correlation analysis (Pearson’s linear correlation coefficient). We analysed 44 microradiograms of first metacarpal bone obtained from 44 postmenopausal women. For imagination we used microfocal x-ray tube (focus diameter 13µm, 25kV, magnification microradiograms was 5x, spatial resolution 40 pl/mm). Each study view was scanned in BMP format using 256 grey scale in 200x200 DPI scan resolution. Scan parameters was evaluated in each case used: parameters energy spectrum of 2D FFT, fractal dimension and image histogram parameters. All patients had standard QCT technique studies. We was high correlation between parameters of bone microstructure described by FFT energy spectrum and BMD - |r|=0,9285 (p<0,05). Correlation between fractal dimension and BMD was |r|=0,8529 (p<0.01). In analysis distribution histogram of intensity high correlation was between mean BMD - |r|=0,9435 (p<0.05).

PL

Tematem pracy jest przedstawienie korelacji parametrów opisujących mikrostrukturę kości gąbczastej pierwszej kości śródręcza z pomiarami BMD (bone mineral density) kręgosłupa wykonanymi metodą QCT. Mikrostrukturę opisano za pomocą następujących grup parametrów: grupa parametrów opisujących histogram obrazu, grupa parametrów opisujących widmo energetyczne dwuwymiarowej transformaty Fouriera obrazu rentgenowskiego struktury kostnej, wartość wymiaru fraktalnego badanego obrazu (FRDIM). Analizie poddano 44 obrazy mikroradiograficzne pierwszej kości śródręcza kobiet w wieku pomenopauzalnym. Do obrazowania mikrostruktury kostnej zastosowano mikroogniskową lampę rentgenowską. Otrzymane radiogramy przetwarzano do postaci cyfrowej przy użyciu skanera BMD pacjentek określono na podstawie badania QCT kręgosłupa. Otrzymano wysokie i bardzo wysokie korelacje parametrów opisujących stan mikrostruktury kostnej z BMD. Wśród parametrów opisujących histogram badanego obrazu najwyższą korelację z BMD wykazała wartość średnia histogramu - |r|=0,9435 (p<0,05). Dla wartości średniej widma energetycznego otrzymano wartość korelacji - |r|=0,9285 (p<0,05). Korelacja wymiaru fraktalnego z BMD wyniosła - |r|=0,8529 (p<0.01).