Application of multidetector computed tomography in the diagnosis of pulmonary embolism and new directions of development

Introduction: Pulmonary embolism (PE) is a condition involving the mechanical part of the closure of the pulmonary arterial thrombus or other embolic material. Is the third the most typical cardiovascular disease - vascular, immediately after a heart attack and stroke. Clinical symptoms are often nonspecific and may result in an incorrect diagnosis. The most common complications of PE include: attack the lungs, impaired heart function, superinfection and development of pulmonary hypertension. Objective: The purpose of the work was to discuss of the technical aspects and the use of multi-slice computed tomography in the diagnosis of PE. The presentation emphasized new directions of development of tomographic methods in imaging thromboembolic events of pulmonary arteries, including multi-energy CT and low-dose techniques. Description of the state of knowledge: Angiography-CT is currently the gold standard in the diagnosis of PE, especially in patients with high and indirect clinical risk. It is characterized by high sensitivity and specificity in contrast enhancement imaging defects within the pulmonary vasculature and blood changes in the pulmonary parenchyma, which may accompany the EP. It also allows to assess the features of right heart overload in the course of massive PE or radiological symptoms associated with the development of chronic PE. Summary: Nowadays, the greatest challenges of CT diagnostics in PE are the improvement of image quality, minimization of artifacts and reduction of the radiation dose to which the patient is exposed. Effective diagnosis of PE is not only good quality CT imaging, but also the efficiency of the process of diagnosis. Hence the development of new applications of CT - called. computer aided diagnosis (CAD)

VISIBILITY DETERMINATION IN BEAM TRACING WITH APPLICATION TO REAL-TIME SOUND SIMULATION

The work presents some aspects of beam tracing technique used in sound simulation. Adaptive Frustum algorithm, which was designed for detecting obstacles via beam subdivision was reviewed from efficiency point of view as well asfor its accuracy. Some possible improvements are suggested, however, they donot fully solve the problems of using this algorithm in real-time applications.Improved algorithm implementation was tested on five scenes with differentcharacteristics and varying complexity

Pricing Rules Comparisonin the Context of Bandwidth Trade, Journal of Telecommunications and Information Technology, 2010, nr 2

In this paper we compare two pricing rules in the context of bandwidth trade. Allocation and pricing rules, together with a set of signals received from independent agents, constitute a market mechanism. In the paper we analyze two pricing rules: well known Vickrey-Clarke-Groves rule (VCG) and the parametric pricing rule (PPR).We apply these pricing rules to the allocation rule specified by the balancing communication bandwidth trade model (BCBT)

Topical treatment of psoriasis

Psoriasis is an autoimmune systemic disease that affects approximately 2-3% of the population. Its symptoms, although focused mainly on the skin, can also have a negative impact on other spheres of the patient's life, including their mental state, because this illness still works with some misunderstanding on the part of society. This chronic, severe inflammatory disease affects mainly skin, but other manifestations, such as joint manifestations, may occur in about 30% of patients. One of the aims of this work is to present the topic of psoriasis, and in particular its topical treatment. It discusses the most commonly used topical preparations for the treatment of psoriasis. Currently thanks to the dynamic development in the fields of medicine, pharmacology and chemistry, schemes and specimens for the effective treatment of psoriasis have been developed. They allow to treat the main, persistent and most affecting the patient’s health symptoms, at the same time improving their quality of life. These specimens are divided into local and systemic ones. They can be used in monotherapy or in combination, depending on the severity of the disease. Topical agents have a symptomatic effect, limited to the maximum remission of skin lesions. These agents not only support the healing process, but also improve the condition of the patient’s skin, which undoubtly has a positive impact on the patient’s daily life

AUTOMATIC PORTAL GENERATION FOR 3D AUDIO - FROM TRIANGLE SOUP TO A PORTAL SYSTEM

The purpose of this paper is to investigate an algorithm for generating an automatic portal system. This has been accomplished based on a given set of triangles. The proposed solution was designed to enhance the performance of a sound beam-tracing engine. This solution can also be used for other areas where portal systems are applicable. The provided technical solution emphasizes the beam tracing engine's requirements. Our approach is based on the work of Haumont et al. (with additional improvements), resulting in improved scene segmentation and lower computational complexity. We examined voxelization techniques and their properties, and have adjusted these to fit the requirements of a beam-tracing engine. As a result of our investigation, a new method for finding portal placement has been developed by adjusting the orientation of the found portals to fit the neighboring scene walls. In addition, we replaced Haumont et al.'s prevoxelization step, which is used for erasing geometrical details (for example, thin walls). This was done by smoothing the distance field that, in effect, eliminated incorrectly positioned portals. The results of our work remove the requirement for walls that separate rooms to have a particular thickness. We also describe a method for building a structure that accelerates real-time queries for determining the area where a given point is located. All of the presented techniques allow for the use of larger sized voxels, which increases performance and reduces memory requirements (not only during the preprocessing phase but also during real-time usage). The proposed solutions were tested using scenarios with scenes of varying complexity

Multicommodity Auction Model for Indivisible Network Resource Allocation, Journal of Telecommunications and Information Technology, 2008, nr 4

In this paper we present the multicommodity auction model BCBT-I that allocates indivisible network resources among bidders. The approach can be considered as a generalization of the basic multicommodity model for balancing communication bandwidth trade (BCBT). The BCBT model assumes that offers concerning inter-node links and point-to-point bandwidth demands can be realized partially. However, in the real-world trade there might be a need to include capacity modularity in the market balancing process. Thus we state the model for balancing communication bandwidth trade that takes into account the indivisibility of traded bandwidth modules. This requires to solve a mixed integer problem and increases computational complexity. Furthermore, the pricing issue appears nontrivial, as the dual prices cannot be longer used to set fair, competitive market prices. For clearing the market, we examine the multicommodity pricing mechanizm based on differentiation of buy and sell market prices

A Framework for Evaluationof Communication Bandwidth Market Models, Journal of Telecommunications and Information Technology, 2010, nr 2

The article presents a method of analysis of market-based models for resource allocation in communication networks. It consists of several stages: classification of a market model, generation of input data, data adaptation to a tested model, test calculations and, finally, presentation and interpretation of results. A set of general criteria to assess various models has been proposed. Tests are run using dedicated computer applications, data is stored in open XML-based format originated in the multicommodity market model. Network topologies are derived from the SNDlib library

Bandwidth Trading: A Comparison of the Combinatorial and Multicommodity Approach, Journal of Telecommunications and Information Technology, 2010, nr 2

Since the telecommunication market becomes more complex and dynamic, a strong need for a new, efficient and flexible bandwidth trading mechanisms appears. We believe that good mechanisms, that allow effective and fair allocation of bandwidth between market participants will help to develop the real competitive bandwidth market. In this paper we compare two different double-sided bandwidth auction mechanisms, that seem to be well suited approaches for trading indivisible units of bandwidth: combinatorial auction c-SeBiDA and multicommodity mechanism BACBR-I. The c-SeBiDA mechanism considers two types of commodities: inter-node links and paths consisting of particular links. Market partici- pants may bid a single link, or a bundle of links, constituting a specific path. The BACBR-I mechanism is a multicommodity exchange model, that allows bidders to place buy offers not only for individual or bundled links, but rather for end-to-end connections. Therefore, it is the decision model that allocates the most efficient links to connections. We run a large set of experiments to test the allocation and computational efficiency obtained under both approaches

Model for Balancing Aggregated Communication Bandwidth Resources, Journal of Telecommunications and Information Technology, 2009, nr 3

In this paper we present a multicommodity bandwidth exchange model for balancing aggregated communication bandwidth resources (BACBR) that allows us to aggregate similar offers. In this model offers submitted to sell (or buy) the same, similar, or equivalent network resources (or demands for end-to-end connections) are aggregated into single commodities. BACBR model is based on the balancing communication bandwidth trade (BCBT) model. It requires much less variables and constraints then original BCBT, however the outcomes need to be disaggregated. The general model for disaggregation is also given in the paper

A New Statistical Reconstruction Method for the Computed Tomography Using an X-Ray Tube with Flying Focal Spot

Abstract This paper presents a new image reconstruction method for spiral cone- beam tomography scanners in which an X-ray tube with a flying focal spot is used. The method is based on principles related to the statistical model-based iterative reconstruction (MBIR) methodology. The proposed approach is a continuous-to-continuous data model approach, and the forward model is formulated as a shift-invariant system. This allows for avoiding a nutating reconstruction-based approach, e.g. the advanced single slice rebinning methodology (ASSR) that is usually applied in computed tomography (CT) scanners with X-ray tubes with a flying focal spot. In turn, the proposed approach allows for significantly accelerating the reconstruction processing and, generally, for greatly simplifying the entire reconstruction procedure. Additionally, it improves the quality of the reconstructed images in comparison to the traditional algorithms, as confirmed by extensive simulations. It is worth noting that the main purpose of introducing statistical reconstruction methods to medical CT scanners is the reduction of the impact of measurement noise on the quality of tomography images and, consequently, the dose reduction of X-ray radiation absorbed by a patient. A series of computer simulations followed by doctor's assessments have been performed, which indicate how great a reduction of the absorbed dose can be achieved using the reconstruction approach presented here