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Biomedizinische Technik. Biomedical Engineering

Amadeus Holmer, Jörg Marotz, Philip Wahl, Michael Dau, Peer W Kämmerer
Blood perfusion is the supply of tissue with blood, and oxygen is a key factor in the field of minor and major wound healing. Reduced perfusion of a wound bed or transplant often causes various complications. Reliable methods for an objective evaluation of perfusion status are still lacking, and insufficient perfusion may remain undiscovered, resulting in chronic processes and failing transplants. Hyperspectral imaging (HSI) represents a novel method with increasing importance for clinical practice. Therefore, methods, software and algorithms for a new HSI system are presented which can be used to observe tissue oxygenation and other parameters that are of importance in supervising healing processes...
July 20, 2018: Biomedizinische Technik. Biomedical Engineering
Taha Haddadifam, Mohammad Azim Karami
Digital silicon photomultiplier (dSiPM) is introduced for diffuse optical imaging (DOI) applications instead of conventional photomultiplier tubes and avalanche photodiodes (APDs) as a state-of-the-art detector. According to the low-level light regime in DOI applications, high sensitivity and high dynamic range (DR) image sensors are needed for DOI systems. dSiPM is proposed as a developing detector which can detect low-level lights. Also, an accurate equation is obtained for calculating the DR of dSiPMs. Different dSiPMs and the corresponding benefits are studied for DOI applications...
July 12, 2018: Biomedizinische Technik. Biomedical Engineering
Axel Boese, Philipp Hündorf, Christoph Arens, Daniel T Friedrich, Michael Friebe
Purpose For the treatment of malignant diseases of the oral cavity and the larynx, a total or partial resection is the standard therapy, while in special cases chemo- and/or external radiation therapy is considered. Transoral access reduces trauma and hospitalization time. Transoral surgery is usually executed using external microscopic imaging. Therefore, the microscope is placed in the visual line of the opening of the mouth and throat. However, specific anatomical structures like the posterior commissure (dorsal end of the vocal cords) are not visible in these procedures...
July 12, 2018: Biomedizinische Technik. Biomedical Engineering
Beibei Zhang, Ning Bi, Chao Zhang, Xiangping Gao, Zhao Lv
Human activity recognition (HAR) is a research hotspot in the field of artificial intelligence and pattern recognition. The electrooculography (EOG)-based HAR system has attracted much attention due to its good realizability and great application potential. Focusing on the signal processing method of the EOG-HAR system, we propose a robust EOG-based saccade recognition using the multi-channel convolutional independent component analysis (ICA) method. To establish frequency-domain observation vectors, short-time Fourier transform (STFT) is used to process time-domain EOG signals by applying the sliding window technique...
July 5, 2018: Biomedizinische Technik. Biomedical Engineering
Michael Czaplik, Mark Ulbrich, Nadine Hochhausen, Rolf Rossaint, Steffen Leonhardt
The gold standard for estimating blood alcohol content (BAC) after alcohol consumption is a blood sample analysis. An innovative technology to estimate BAC is based on impedance cardiography and bioimpedance spectroscopy (BIS). This study investigated whether it is possible to estimate increasing blood alcohol levels during a drinking trial with bioimpedance measurement techniques. Twenty-one healthy volunteers were assigned to a test (ethanol) group (ETH) or a reference group (H2O). After baseline measurements, the ETH group ingested 120 ml of vodka, followed by a resorption phase of 50 min...
June 27, 2018: Biomedizinische Technik. Biomedical Engineering
Randy E S Harnarinesingh, Chanan S Syan
Brain-computer interface (BCI) applications such as keyboard control and vehicular navigation present significant assistive merit for disabled individuals. However, there are limitations associated with BCI paradigms which restrict a wider adoption of BCI technology. For example, rapid serial visual presentation (RSVP) paradigms can induce seizures in photosensitive epileptic subjects. This paper evaluates the novel mirrored-word reading paradigm (MWRP) for BCI implementation using an offline experimental study...
June 27, 2018: Biomedizinische Technik. Biomedical Engineering
Halim Kovacı, Ali Fatih Yetim, Ayhan Çelik
Spinal implants are commonly used in the treatment of spinal disorders or injuries. However, the biomechanical analyses of them are rarely investigated in terms of both biomechanical and clinical perspectives. Therefore, the main purpose of this study is to investigate the effects of rod diameter on the biomechanical behavior of spinal implants and to make a comparison among them. For this purpose, three spinal implants composed of pedicle screws, setscrews and rods, which were manufactured from Ti6Al4V, with diameters of 5...
June 23, 2018: Biomedizinische Technik. Biomedical Engineering
Andrea Balasso, Marco Fritzsche, Dieter Liepsch, Sascha Prothmann, Jan Stefan Kirschke, Sergey Sindeev, Sergey Frolov, Benjamin Friedrich
The presence of high-frequency velocity fluctuations in aneurysms have been confirmed by in-vivo measurements and by several numerical simulation studies. Only a few studies have located and recorded wall vibrations in in-vitro experiments using physiological patient models. In this study, we investigated the wall fluctuations produced by a flowing perfusion fluid in a true-to-scale elastic model of a cerebral fusiform aneurysm using a laser Doppler vibrometer (LDV). The model was obtained from patient data...
June 23, 2018: Biomedizinische Technik. Biomedical Engineering
Michael Stiehm, Carolin Wüstenhagen, Stefan Siewert, Hüseyin Ince, Niels Grabow, Klaus-Peter Schmitz
Bioresorbable scaffolds (BRS) promise to be the treatment of choice for stenosed coronary vessels. But higher thrombosis risk found in current clinical studies limits the expectations. Three hemodynamic metrics are introduced to evaluate the thrombosis risk of coronary stents/scaffolds using transient computational fluid dynamics (CFD). The principal phenomena are platelet activation and effective diffusion (platelet shear number, PSN), convective platelet transport (platelet convection number, PCN) and platelet aggregation (platelet aggregation number, PAN) were taken into consideration...
June 22, 2018: Biomedizinische Technik. Biomedical Engineering
Sotirios Spiliopoulos, Vera Hergesell, Andrae Wasler, Otto Dapunt
Due to the declining instances of organ donation, total artificial heart (TAH) therapy is of increasing importance for the management of end-stage biventricular heart failure. We introduce the currently most important established and novel TAH systems (SynCardia, CARMAT, ReinHeart, BiVACOR), report clinical outcomes and discuss technical requirements for the successful implementation of TAH therapy as an alternative to cardiac transplantation.
June 14, 2018: Biomedizinische Technik. Biomedical Engineering
Sebastian Zaunseder, Alexander Trumpp, Daniel Wedekind, Hagen Malberg
Over the last few years, the contactless acquisition of cardiovascular parameters using cameras has gained immense attention. The technique provides an optical means to acquire cardiovascular information in a very convenient way. This review provides an overview on the technique's background and current realizations. Besides giving detailed information on the most widespread application of the technique, namely the contactless acquisition of heart rate, we outline further concepts and we critically discuss the current state...
June 13, 2018: Biomedizinische Technik. Biomedical Engineering
Jan-Christoph Edelmann, Dominik Mair, Thomas Ussmueller
This manuscript introduces a novel concept for measuring coil coupling for extremely loose-coupled coils (coupling factors k<10-6; mutual inductance values M<10-10 H). Such a coupling is found everywhere where the ratio of solenoid diameter to coil spacing is >50. Measuring these quantities with a low-power technology requires a sophisticated setup that goes beyond the sensitivity of state-of-the art approaches. The methodology is validated using laboratory measurements with three sets of solenoids (two ferrite-cored, one air-cored) and numerical simulations with COMSOL Multiphysics 5...
June 12, 2018: Biomedizinische Technik. Biomedical Engineering
Jan Karsten, Nicolas Voigt, Hans-Joerg Gillmann, Thomas Stueber
There is no agreement on gold standard method for positive end-expiratory pressure (PEEP) titration. Electrical impedance tomography (EIT) may aid in finding the optimal PEEP level. In this pilot trial, we investigated potential differences in the suggested optimal PEEP (BestPEEP) as derived by respiratory compliance and EIT-derived parameters. We examined if compliance-derived PEEP differs with regard to the regional ventilation distribution in relation to atelectasis and hyperinflation. Measurements were performed during an incremental/decremental PEEP trial in 15 ventilated intensive care patients suffering from mild-to-moderate impairment of oxygenation due to sepsis, pneumonia, trauma and metabolic and ischemic disorders...
June 6, 2018: Biomedizinische Technik. Biomedical Engineering
Behrouz Alizadeh Savareh, Hassan Emami, Mohamadreza Hajiabadi, Seyed Majid Azimi, Mahyar Ghafoori
PURPOSE: Manual brain tumor segmentation is a challenging task that requires the use of machine learning techniques. One of the machine learning techniques that has been given much attention is the convolutional neural network (CNN). The performance of the CNN can be enhanced by combining other data analysis tools such as wavelet transform. MATERIALS AND METHODS: In this study, one of the famous implementations of CNN, a fully convolutional network (FCN), was used in brain tumor segmentation and its architecture was enhanced by wavelet transform...
May 29, 2018: Biomedizinische Technik. Biomedical Engineering
Mohamed Rouis, Abdelkrim Ouafi, Salim Sbaa
The recorded phonocardiogram (PCG) signal is often contaminated by different types of noises that can be seen in the frequency band of the PCG signal, which may change the characteristics of this signal. Discrete wavelet transform (DWT) has become one of the most important and powerful tools of signal representation, but its effectiveness is influenced by the issue of the selected mother wavelet and decomposition level (DL). The selection of the DL and the mother wavelet are the main challenges. This work proposes a new approach for finding an optimal DL and optimal mother wavelet for PCG signal denoising...
May 23, 2018: Biomedizinische Technik. Biomedical Engineering
Syed Rashid Habib
OBJECTIVE: The aim of this in vitro research study was to evaluate the vertical marginal discrepancies of zirconia (Zr) cores fabricated by five different computer-aided design and manufacturing (CAD/CAM) systems using a digital microscope. MATERIALS AND METHODS: A total of 60 specimens were prepared and randomly divided into five groups (n=12 each) using the following systems: Ceramill Motion 2 (CM, Amanngirrbach, Germany); Weiland (WI, Ivoclar Vivadent, USA); Cerec (CS, Sirona Dental, USA); Zirkonzahn (ZZ, Gmbh Bruneck, Italy) and Cad4dent (CD, Canada)...
May 18, 2018: Biomedizinische Technik. Biomedical Engineering
Sebastian Stach, Olga Kędzia, Żaneta Garczyk, Zygmunt Wróbel
The main goal of the study was to develop a model of the degree of surface porosity of a biomaterial intended for implants. The model was implemented using MATLAB. A computer simulation was carried out based on the developed model, which resulted in a two-dimensional image of the modelled surface. Then, an algorithm for computerised image analysis of the surface of the actual oxide bioceramic layer was developed, which enabled determining its degree of porosity. In order to obtain the confocal micrographs of a few areas of the biomaterial, measurements were performed using the LEXT OLS4000 confocal laser microscope...
May 18, 2018: Biomedizinische Technik. Biomedical Engineering
Georg Daeschlein, Rico Rutkowski, Stine Lutze, Sebastian von Podewils, Claudia Sicher, Thomas Wild, Hans-Robert Metelmann, Thomas von Woedkte, Michael Jünger
An important clinical potential of cold atmospheric plasma (CAP) lies in tumor and wound treatment, whereby the last-mentioned is well-referenced already. However, the underlying mechanisms of improved wound healing have not been sufficiently clarified yet, in particular the influence of CAP on microcirculation. Hyperspectral imaging (HSI) enables the visualization of microcirculation of large tissue areas, thus this technique seems to be a candidate to examine CAP effects on perfusion and oxygen saturation in wounds...
May 4, 2018: Biomedizinische Technik. Biomedical Engineering
Spiros Zinelis, Youssef S Al Jabbari
This study was conducted to evaluate the failure mechanism of clinically failed Hedstrom (H)-files. Discarded H-files (n=160) from #8 to #40 ISO sizes were collected from different dental clinics. Retrieved files were classified according to their macroscopic appearance and they were investigated under scanning electron microscopy (SEM) and X-ray micro-computed tomography (mXCT). Then the files were embedded in resin along their longitudinal axis and after metallographic grinding and polishing, studied under an incident light microscope...
May 1, 2018: Biomedizinische Technik. Biomedical Engineering
Vera Miler Jerkovic, Vladimir Kojic, Natasa Dragasevic Miskovic, Tijana Djukic, Vladimir S Kostic, Mirjana B Popovic
The purpose of this paper is to emphasize the importance of in-air movement besides on-surface movement for handwriting analysis. The proposed method uses a classification of drawing healthy subjects and subjects with Parkinson's disease, according to their on-surface and in-air handwriting parameters during their writing on a graphical tablet. Experimental results on real data sets demonstrate that the highest accuracy of subject's classification was obtained by combining both on-surface and in-air kinematic parameters...
May 1, 2018: Biomedizinische Technik. Biomedical Engineering
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