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Open access

Piotr Karwat, Ziemowit Klimonda, Michał Sęklewski, Marcin Lewandowski and Andrzej Nowicki

Abstract

Ultrasonic methods of human body internal structures imaging are being continuously enhanced. New algorithms are created to improve certain output parameters. A synthetic aperture method (SA) is an example which allows to display images at higher frame-rate than in case of conventional beam-forming method.

Higher computational complexity is a limitation of SA method and it can prevent from obtaining a desired reconstruction time. This problem can be solved by neglecting a part of data. Obviously it implies a decrease of imaging quality, however a proper data reduction technique would minimize the image degradation.

A proposed way of data reduction can be used with synthetic transmit aperture method (STA) and it bases on an assumption that a signal obtained from any pair of transducers is the same, no matter which transducer transmits and which receives. According to this postulate, nearly a half of the data can be ignored without image quality decrease.

The presented results of simulations and measurements with use of wire and tissue phantom prove that the proposed data reduction technique reduces the amount of data to be processed by half, while maintaining resolution and allowing only a small decrease of SNR and contrast of resulting images.

Open access

Piotr Karwat, Jerzy Litniewski, Tamara Kujawska, Wojciech Secomski and Kazimierz Krawczyk

Abstract

Therapeutic and surgical applications of focused ultrasound require monitoring of local temperature rises induced inside tissues. From an economic and practical point of view ultrasonic imaging techniques seem to be the most suitable for the temperature control. This paper presents an implementation of the ultrasonic echoes displacement estimation technique for monitoring of local temperature rise in tissue during its heating by focused ultrasound The results of the estimation were compared to the temperature measured with thermocouple. The obtained results enable to evaluate the temperature fields induced in tissues by pulsed focused ultrasonic beams using non-invasive imaging ultrasound technique

Open access

Marcin Lewandowski, Mateusz Walczak, Piotr Karwat, Beata Witek and Paweł Karłowicz

Abstract

A new ultrasound digital transcranial Doppler system (digiTDS) is introduced. The digiTDS enables diagnosis of intracranial vessels which are rather difficult to penetrate for standard systems. The device can display a color map of flow velocities (in time-depth domain) and a spectrogram of a Doppler signal obtained at particular depth. The system offers a multigate processing which allows to display a number of spectrograms simultaneously and to reconstruct a flow velocity profile.

The digital signal processing in digiTDS is partitioned between hardware and software parts. The hardware part (based on FPGA) executes a signal demodulation and reduces data stream. The software part (PC) performs the Doppler processing and display tasks. The hardware-software partitioning allowed to build a flexible Doppler platform at a relatively low cost.

The digiTDS design fulfills all necessary medical standards being a new useful tool in the transcranial field as well as in heart velocimetry research.

Open access

Piotr Chomik, Paulina Gil-Kulik, Malgorzata Filas, Agnieszka Wojcieszek, Mateusz Wilinski, Jolanta Karwat, Lidia Kotula, Alicja Niedojadlo, Marcin Czop, Anna Bogucka-Kocka, Maria Cioch, Ryszard Pluta and Janusz Kocki

ABSTRACT

The BIRC6 gene encodes the Bruce (Apollon) protein. This belongs to the III class of Inhibitors of the Apoptosis Protein (IAP) and demonstrates anti-apoptotic activity (binding, inhibiting and degrading the caspases). Moreover, the Bruce protein shows multilevel activities and additional functions. The Bruce protein is involved in the maintenance of cell viability, and it is also suggested that it plays an important role in cell proliferation and diversification. Many researchers have noticed elevated BIRC6 gene expression in cell lines of brain cancer and ovarian carcinoma, leukemia, breast cancer and even in colorectal cancer tissues. Resistance to chemotherapy-inducted apoptosis in cancers characterized by BIRC6 gene over-expression was also reported. The aim of the study was to assess the BIRC6 gene expression in peripheral blood lymphocytes of patients diagnosed with chronic lymphocytic leukemia.

Open access

Ziemowit Klimonda, Jerzy Litniewski, Piotr Karwat and Andrzej Nowicki

Abstract

The soft tissue attenuation is an interesting parameter from medical point of view, because the value of attenuation coefficient is often related to the state of the tissue. Thus, the imaging of the attenuation coefficient distribution within the tissue could be a useful tool for ultrasonic medical diagnosis. The method of attenuation estimation based on tracking of the mean frequency changes in a backscattered signal is presented in this paper. The attenuation estimates are characterized by high variance due to stochastic character of the backscattered ultrasonic signal and some special methods must be added to data processing to improve the resulting images. The following paper presents the application of Spatial Compounding (SC), Frequency Compounding (FC) and the combination of both. The resulting parametric images are compared by means of root-mean-square errors. The results show that combined SC and FC techniques significantly improve the quality and accuracy of parametric images of attenuation distribution.

Open access

Paulina Gil-Kulik, Alicja Niedojadło, Marcin Feldo, Jolanta Karwat, Lidia Kotuła, Piotr Chomik, Ilona Dudek, Małgorzata Filas, Agnieszka Wojcieszek, Tomasz Zubilewicz, Anna Bogucka-Kocka and Janusz Kocki

Abstract

Introduction. Recent research shows that programmed cell death has great importance in the pathomechanism of atherosclerosis. The BIRC5 and BIRC6 genes belong to Class III IAPs with the anti-apoptotic effect. The proteins display multidirectional action. According to the available literature, in addition to the effect of apoptosis inhibition they also display other properties. It is suggested that they play an important role in the processes of proliferation and cellular differentiation. Aim. The aim of the study was to assess the expression of the BIRC5 and BIRC6 genes in normal peripheral blood lymphocytes and in peripheral blood lymphocytes of patients diagnosed with atherosclerosis. Material and methods. The analysis was carried out on RNA samples obtained from peripheral blood lymphocytes of 21 patients with diagnosed atherosclerosis. The specific fragment of the analysed gene was obtained through amplification with the use of cDNA synthesised in the reaction of reverse transcription. The test of expression was conducted with the use of the Real-Time PCR method. In the studied cases, the level of expression of the analysed gene was compared to the level of expression of the reference gene, B2M. Results. The study showed that mRNA of the BIRC5 and BIRC6 genes is present in the cells of patients with atherosclerosis, as well as in the cells of healthy individuals. The cells taken from the patients with atherosclerosis were mainly characterized by an increased gene expression in comparison to the normal cells. Conclusion. Increased BIRC6 and BIRC5 gene expression in the cells of the patients with atherosclerosis can suggest an increased amount of the inhibitor protein BRUCE and survivin, and also decreased sensitivity of cells to apoptosis. In the case of the patients who had significantly higher expression of the BIRC6 gene in lymphocytes compared to the norm, hypertension and diabetes mellitus were more common