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1

A sequential extended regional maxima transformation with contrast-based criterion for image segmentation

Markiewcz T., Dziekiewicz M., Kozłowski W.

Przegląd Elektrotechniczny

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2015

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R. 91, nr 7

13-15

EN

This paper describes the sequential extended regional maxima transformation combined with the contrast-based criterion for establishing a sub-optimal h-value. This method is applied to computed tomography angiography and histological image segmentation. The presented method is effective for high and low contrasted arteries, which are detected in 94.3% exactly and in 97.7% with area tolerance, and also for cell nuclei segmentation with near 95% of accuracy.

PL

W pracy przedstawiono zastosowanie transformaty rozszerzonych maksimów lokalnych połączoną z kryterium opartym na kontraście celem ustalenia suboptymalnej wartości parametru h. Zaproponowana metoda została wykorzystana do analizy obrazów tomografii komputerowej naczyń oraz obrazów histologicznych. Okazała się ona wysoce skuteczna dla identyfikacji naczyń z różnym poziomem zakontrastowania, pozwalając na około 96% ich rozpoznawalność, jak również blisko 95% skuteczność w segmentacji jąder komórek w obrazach mikroskopowych.

2

Thresholding techniques for segmentation of atherosclerotic plaque and lumen areas in vascular arteries

Markiewicz T., Dziekiewicz M., Osowski S., Maruszyński M., Kozłowski W., Bogusławska-Walecka R.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2015

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Vol. 63, nr 1

269--280

EN

The paper develops the automatic methods of segmentation of the blood vessel area in the images of the multi-slice computed tomography, allowing to separate the lumen from the atherosclerotic plaque areas. The solution is based on the application of different implementations of thresholding, including between class variance in a bimodal mode, Gaussian mixture modeling, clustering technique, polynomial and multilayer perceptron approximations. These methods are compared with many examples of arteries of different percentage of the plaque occupancy in the iliac and femoral arteries. The numerical results of segmentation have been verified by the medical experts and prove its usefulness in medical practice. The presented system can find application in an automatic evaluation of the atherosclerosis progression/regression of patients on the basis of sequence of Computed Tomography slice images.

3

Recognition of atherosclerotic plaques and their extended dimensioning with computerized tomography angiography imaging

Markiewicz T., Dziekiewicz M., Maruszyński M., Bogusławska-Walecka R., Kozłowski W.

International Journal of Applied Mathematics and Computer Science

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2014

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Vol. 24, no. 1

33--47

EN

In this paper the authors raise the issue of automatic discrimination of atherosclerotic plaques within an artery lumen based on numerical and statistical thresholding of Computerized Tomography Angiographic (CTA) images and their advanced dimensioning as a support for preoperative vessel assessment. For the study, a set of tomograms of the aorta, as well as the ilio-femoral and femoral arteries were examined. In each case a sequence of about 130–480 images of the artery cutoff planes were analyzed prior to their segmentation based on morphological image transformation. A crucial step in the staging of atherosclerotic alteration is recognition of the plaque in the CTA image. To solve this problem, statistical and linear fitting methods, including the least-squares approximation by polynomial and spline polynomial functions, as well as the error fitting function were used. Also, new descriptors of atherosclerotic changes, such as the lumen decrease factor, the circumference occupancy factor, and the convex plaque area factor, are proposed as a means of facilitating preoperative vessel examination. Finally, ways to reduce the computational time are discussed. The proposed methods can be very useful for automatic quantification of atherosclerotic changes visualized by CTA imaging.

4

Pro-angiogenic effects of X-rays on murine endothelial cells

Lisiak E., Dziekiewicz M., Meineke V., Bilski M., Janiak M.

Nukleonika

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2005

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Vol. 50,suppl.2

17-20

EN

Recently, significant attention has been paid to the possibility of thwarting cancer progression by inhibition of neoangiogenesis (formation of new blood vessels) in growing tumors. Although general mechanisms of angiogenesis have been elucidated, virtually nothing is known about the effects of low doses of ionizing radiation on pro-angiogenic properties of endothelial cells. In the present study, we evaluated the effects of a low (0.2 Gy), intermediate (1 Gy), and high (4 Gy) doses of X-rays on a few angiogenesis-related parameters of isolated murine endothelial cells. We show here that 24 to 48 hours after irradiation with 0.2 Gy the cell proliferation was inhibited to a similar extent as after the exposure to 1 Gy. Also, adhesion of the 0.2 Gy-irradiated cells to both gelatin and MatrigelŽ was inhibited 24 hours post-exposure, whereas irradiation with 1 or 4 Gy resulted in the increased adhesion of the cells to these substrata. Similar effects were observed during the "wound" migration assay. Finally, 24 hours after exposure of the cells to 0.2 Gy of X-rays, the surface expression of the â3 integrin subunit was down-regulated, whereas irradiations with 1 and 4 Gy of X-rays resulted in the significantly elevated expression of this subunit. These results indicate that proliferating endothelial cells are sensitive in vitro to relatively low doses of ionizing radiation