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1

Modelling the temperature-dependent RF ablation produced by the multi-tine electrode

Gas Piotr

Przegląd Elektrotechniczny

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2020

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R. 96, nr 1

48--51

EN

The paper discusses a thermal ablation of liver tissue with a multi-tine probe. The 3D model of such applicator with evenly distributed 2–5 arms was placed in hepatic tissue near a cylindrical vessel with circulating blood. The temperature of the surrounding tissue was regulated within defined limits by changing the voltage employed on the RF electrode. The current study examines influence of temperature-dependent and constant parameters of liver tissue on thermal efficiency of ablation procedure. As presented, a blood flowing in the blood vessel causes the cooling of tissue, which requires the electrode voltage to be increased to maintain the set therapeutic levels of temperatures. Interestingly, even larger changes in electrode potential are required in the case of temperature-dependent ablation with a blood vessel.

PL

Praca omawia termiczną ablację tkanki wątroby za pomocą sondy wielopalcowej. Model 3D takiego aplikatora o równomiernie rozmieszczonych 2–5 ramionach umieszczono w tkance wątroby w pobliżu cylindrycznego naczynia z przepływającą krwią. Temperatura otaczającej tkanki była regulowana w określonych granicach poprzez zmianę napięcia przyłożonego na elektrodzie RF. W pracy zbadano wpływ zależnych od temperatury i stałych parametrów tkanki wątroby na sprawność ablacji cieplnej. Jak pokazano, krew płynąca w naczyniu krwionośnym powoduje chłodzenie tkanki, co wymaga zwiększenia napięcia elektrody, aby utrzymać zadane poziomy terapeutyczne temperatury. Co ciekawe, nawet większe zmiany potencjału elektrody są wymagane w przypadku zależnej od temperatury ablacji w obecności naczynia krwionośnego.

2

A fully automatic computer-aided diagnosis system for hepatocellular carcinoma using convolutional neural networks

Li Jing, Wu Yurun, Shen Nanyan, Zhang Jiawen, Chen Enlong, Sun Jie, Deng Zongqian, Zhang Yuchen

Biocybernetics and Biomedical Engineering

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2020

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Vol. 40, no. 1

238--248

EN

The cancer of liver, which is the leading cause of cancer death, is commonly diagnosed by comparing the changes of gray level of liver tissue in the different phases of the patient's CT images. To aid the doctor in reducing misdiagnosis or missed diagnosis, a fully automatic computer-aided diagnosis (CAD) system is proposed to diagnose hepatocellular carcinoma (HCC) using convolutional neural network (CNN) classifier. The automatic segmentation and classification are two core technologies of the proposed CAD system, which are both realized based on CNN. The segmentation of liver and tumor is implemented by a fully convolutional networks (FCN) based on a fine tuning VGG-16 model with two additional 'skip structures' using a weighted loss function which helps to solve the problem of inaccurate tumor segmentation caused by the inevitably unbalanced training data. HCC classification is implemented by a 9-layer CNN classifier, whose input is a 4-channel image data constructed by combining the segmentation result of FCN with the original CT image. A total of 165 venous phase CT images including 46 diffuse tumors, 43 nodular tumors, and 76 massive tumors are used to evaluate the performance of the proposed CAD system. The classification accuracy of CNN classifier for diffuse, nodular and massive tumors are 98.4%, 99.7% and 98.7% respectively, which are significantly improved in contrast with the traditional feature-based ANN and SVM classifiers. The proposed CAD system, which is unaffected by the difference of preprocessing method and feature type, is proved satisfactory and feasible by the test set.

3

Influence of multi-tine electrode configuration in realistic hepatic RF ablative heating

Gas Piotr, Wyszkowska Joanna

Archives of Electrical Engineering

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2019

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Vol. 68, nr 3

521--533

EN

Percutaneous RF ablation is one of alternative treatment for non-surgical liver tumors. Ablative changes in hepatic tissue can be successfully estimated using the finite element method. The authors created a 3D model of a multi-tine applicator immersed in liver tissue, and then determined the optimal values of voltage applied to such an RF electrode, which do not exceed the therapeutic temperature range valid during thermal ablation procedure. Importantly, the simulations were carried out for the RF electric probes with 2 to 5 evenly spaced arms. Additionally, the thermal damage of hepatic tissue for multi-armed applicators working at pre-defined limit values of voltages was established based on the Arrhenius model.

4

Logistyczne ujęcie badań zmian ogniskowych wątroby u młodych dorosłych

Sirak J.

Logistyka

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2015

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nr 4

8292--8300, CD 2

PL

Zmiany ogniskowe wątroby stanowią bardzo istotny problem diagnostyczny i terapeutyczny. Dzięki logistycznemu podejściu w diagnozowaniu chorób nowotworowych zmiany ogniskowe wątroby są często wykrywane przypadkowo w grupie coraz to młodszych pacjentów, szczególnie u kobiet w grupie wiekowej między 31 a 40-tym rokiem życia. U młodych dorosłych najczęściej diagnozowane są zmiany przerzutowe do wątroby, wykrywane głównie w badaniu ultrasonograficznym. Badania laboratoryjne nie mają tak istotnego znaczenia w przypadku diagnozowania zmian ogniskowych, gdyż wirusy hepatotropowe powodujące marskość i nowotwory wątroby u pacjentów w danej grupie wiekowej w głównej mierze są ujemne. Nieprawidłowości w wynikach badań laboratoryjnych dotyczyły przede wszystkim markera CA 19-9 oraz enzymu wątrobowego–gammaglutamylotranspeptydazy. Badania histopatologiczne zmiany ogniskowej wątroby mają na celu postawienie ostatecznego rozpoznania, w przypadku gdy wynik badania obrazowego jest niejednoznaczny.

EN

Focal lesions of the liver are a very important diagnostic and therapeutic problem. Thanks to the logistic approach in the diagnosis of cancer of the liver focal lesions are often detected accidentally in the group of increasingly younger patients, particularly in women groups aged between 31 and 40. By young adults most frequently are diagnosed metastatic lesions to the liver mainly detected by ultrasonography. Laboratory tests do not have such importance for the diagnosis of focal lesions, as hepatotropic viruses that cause cirrhosis and liver cancer by patients in a particular age group are mainly negative. Irregularities in the results of laboratory tests were related primarily to the marker CA 19-9 and liver-enzyme gammaglutamyltranspeptydase. Histopathological tests of the changes in focal lesions of the liver intend to place final diagnosis when imaging test result is inconclusive.