Adam Piórkowski

Outcome in adult patients after arterial switch operation for transposition of the great arteries

BACKGROUND The arterial switch operation (ASO) is currently the treatment of choice in neonates with transposition of the great arteries (TGA). The outcome in childhood is encouraging but only limited data for long-term outcome into adulthood exist. METHODS AND RESULTS We studied 145 adult patients (age>16, median 25 years) with ASO followed at our institution. Three patients died in adulthood (mortality 2.4/1000-patient-years). Most patients were asymptomatic and had normal left ventricular function. Coronary lesions requiring interventions were rare (3 patients) and in most patients related to previous surgery. There were no acute coronary syndromes. Aortic root dilatation was frequent (56% patients) but rarely significant (>45 mm in 3 patients, maximal-diameter 49 mm) and appeared not to be progressive. There were no acute aortic events and no patient required elective aortic root surgery. Progressive neo-aortic-valve dysfunction was not observed in our cohort and only 1 patient required neo-aortic-valve replacement. Many patients (42.1%), however, had significant residual lesions or required reintervention in adulthood. Right ventricular outflow tract lesions or dysfunction of the neo-pulmonary-valve were frequent and 8 patients (6%) required neo-pulmonary-valve replacement. Cardiac interventions during childhood (OR 3.0, 95% CI 1.7-5.4, P<0.0001) were strong predictors of outcome (cardiac intervention/significant residual lesion/death) in adulthood. CONCLUSIONS Adult patients with previous ASO remain free of acute coronary or aortic complications and have low mortality. However, a large proportion of patients require re-interventions or present with significant right sided lesions. Life-long cardiac follow-up is, therefore, warranted. Periodic noninvasive surveillance for coronary complications appears to be safe in adult ASO patients.

A Statistical Dominance Algorithm for Edge Detection and Segmentation of Medical Images

This article proposes an algorithm which performs the initial stage of edge detection or segmentation. The algorithm counts the number of pixels with a given relation to the central point of the neighborhood. The output image is a statistical result of the dominance of points over their neighborhoods and allows the classification of these points to be determined (peak, valley, and slope). Therefore, this solution allows the impact of noise or uneven illumination in image results to be reduced. The basic features of the proposed algorithm are considered in this paper. Application of the algorithm is illustrated in the context of image segmentation of a corneal endothelium with a specular microscope, images of specimens of the brain tissue, and hand radiographs.

Load Balancing for Heterogeneous Web Servers

A load balancing issue for heterogeneous web servers is described in this article. The review of algorithms and solutions is shown. The selected Internet service for on-line echocardiography training is presented. The independence of simultaneous requests for this server is proved. Results of experimental tests are presented.

The Transesophageal Echocardiography Simulator Based on Computed Tomography Images

Simulators are a new tool in education in many fields, including medicine, where they greatly improve familiarity with medical procedures, reduce costs, and, importantly, cause no harm to patients. This is so in the case of transesophageal echocardiography (TEE), in which the use of a simulator facilitates spatial orientation and helps in case studies. The aim of the project described in this paper is to simulate an examination by TEE. This research makes use of available computed tomography data to simulate the corresponding echocardiographic view. This paper describes the essential characteristics that distinguish these two modalities and the key principles of the wave phenomena that should be considered in the simulation process, taking into account the conditions specific to the echocardiography. The construction of the CT2TEE (Web-based TEE simulator) is also presented. The considerations include ray-tracing and ray-casting techniques in the context of ultrasound beam and artifact simulation. An important aspect of the interaction with the user is raised.

A Model of a System for Stream Data Storage and Analysis Dedicated to Sensor Networks of Embankment Monitoring

Contemporary monitoring systems are a source of data streams. Processing of this data is an interesting issue from both a performance and data storage perspective. It is worth paying attention to the concept of stream database management systems, which are a hybrid that allows for efficient analysis of the data stream and provide a set of implemented statistical methods.

Analysis of selected component technologies efficiency for parallel and distributed seismic wave field modeling

In this article efficiency of using component-based software for seismic wave field modeling is presented. The most common component solutions like: .NET, Java and Mono were analyzed for various operating systems and hardware platform combinations. Obtained results clearly indicate that the component approach is able to give satisfactory results in this kind of applications, but global solution efficiency can strongly depends on operating system and hardware. The most important conclusion of this work is that for this kind of computations and at this stage of component technology development there are almost no differences between commercial and free platforms.

Creating 3D Web-Based Viewing Services for DICOM Images

This paper presents the design of Web-based medical image viewing system. It allows easy access to the selected DICOM data. The purpose of this application is to provide 3D results of computer tomography as a projection at any angle. This system contains of modules for data storing, projection creating and image file creating. In the experimental part two common web technologies (Java and ASP) were tested in terms of performance for designed system.

Cell Detection in Corneal Endothelial Images Using Directional Filters

The article presents an algorithm for the detection of corneal endothelium cells in images obtained with confocal microscopy (KH algorithm). Firstly, preprocessing issues are presented. The proposed methodology is based on image processing algorithms, especially filters. The method outputs images that are prepared for further analysis, e.g. stereological measurements. Each step of the algorithm is discussed in detail and other methods of digital images processing are compared to the research results.

Towards Precise Segmentation of Corneal Endothelial Cells

This article describes an algorithm for defining the precise, objective, repeatable and unambiguous segmentation of cells in images of the corneal endothelium. This issue is important for clinical purposes, because the quality of the grid cells is assessed on the basis of segmentation. Other solutions, including commercial software, do not always mark cell boundaries along lines of lowest brightness.

A Concept of Time Windows Length Selection in Stream Databases in the Context of Sensor Networks Monitoring

Monitoring systems are a source of large amounts of data. These streams of data flow down as information which, in the case of sensor networks is often associated with the measurement of the selected physical signals. Processing of these data is a non-trivial issue, because accurate calculations often require dedicated solutions and large computing power.