bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of open-source software for the lung segmentation
Authors: Alnaser Aseel , Gong Bo , Moeller Knut 
Published: December 2016

Abstract
In this study we evaluated open-source software for lung segmentation. Several parameters which emphasize on functionality, usability, image quality and 3D export are considered for this evaluation. Based on these parameters, a scoring system is generated. Our preliminary evaluation results indicated that the Pulmonary toolkit obtains the best overall performance according to the scoring system. However, the ranking of software shows a certain variation among different criteria. The selection of software should regard the focus and the specific interest of the user.
Radiopacity assessment of neurovascular implants
Authors: Hoffmann Thomas , Gugel Sebastian , Beuing Oliver , Rose Georg 
Published: December 2016

Abstract
An experimental method for radiopacity evaluation of neurovascular implants is presented. State of the art methods are described for cardiovasular implants. To extend the methods to neurovascular devices, imaging parameters were determined from clinical radiography data sets and protocols. To reduce background noise, a thresholding method is introduced. This method is evaluated on a setup with four different laser cut and braided stents. The results are compared to current evaluation methods without filtering. It is shown that unfiltered methods underestimate the radiopacity by 0.89 mm ± 0.21 mm (aluminum equivalent). The introduced method is highly repeatable and uses modern clinical imaging technology. Thus an image evaluation under realisitc conditions is possible. Slightly visible vascular devices and implants can be compared with high accuracy.
Rapid prototyping of replica knee implants for in vitro testing
Authors: Verjans Mark , Asseln Malte , Radermacher Klaus 
Published: December 2016

Abstract
The understanding of the complex biomechanics of the knee is a key for an optimal implant design. To easily investigate the influence of prosthetic designs on knee biomechanics a rapid prototyping workflow for knee implants has been developed and evaluated. Therefore, different manufacturing technologies and post-treatment methods have been examined and overall seven different replica knee implants were manufactured. For evaluation, the manufacturing properties such as surface accuracy and roughness were determined and kinematic behaviour was investigated in a novel knee testing rig. It was carried out that PolyJet-Modelling with a sanded surface resulted in changed kinematic patterns compared to a usual CoCr-UHMWPE implant. However, fused deposition modelling using ABS and subsequent surface smoothening with acetone vapor showed the lowest roughness of the manufactured implants and only minor kinematic differences. For this reason this method constitutes a promising approach towards an optimal implant design for improved patient-satisfaction and long lifetime of the implant. Finally the workflow is not only limited to the knee.
Protecting ultra- and hyperhydrophilic implant surfaces in dry state from loss of wettability
Authors: Lüers Steffen , Laub Markus , Jennissen Herbert P. 
Published: December 2016

Abstract
Ultrahydrophilic titanium miniplates with sandblasted and acid etched (SLA) surfaces were protected from loss of hydrophilicity by an exsiccation layer of salt and stored in a dry state. Various salts in different concentrations were tested in respect to their conservation capacity and optical appearance. Potassium phosphate buffer in a specified composition appeared to be optimal. This optimal system was applied in a long time storage experiment showing no loss of hydrophilicity over years. It was also transferred with success to hyperhydrophilic dental implants.
Plasma treatment on novel carbon fiber reinforced PEEK cages to enhance bioactivity
Authors: Banghard Michael , Freudigmann Christian , Silmy Kamel , Stett Alfred , Bucher Volker 
Published: December 2016

Abstract
Carbon fiber reinforced polyetheretherketone (CFR-PEEK) has similar mechanical properties to human bone and is considered as the best alternative material to substitute titanium for spine cage implants. To compensate its poor osteogenic properties and limited bioinertness, CFR-PEEK was coated with a thin film of titanium. In the study, we investigated the biological response in vitro of titanium coated CFR-PEEK with different vacuum plasma pretreatments. The so modified surface revealed first hints for a good cell response by excellent cell adhesion and morphology of human osteoblast – like cells MG 63 (ATXX:’CRL-1427). Thus, the findings show that surface roughness of CFR-PEEK material has a profound effect on the biological activity via vacuum plasma treatment.
Wear of a total intervertebral disc prosthesis
Authors: Micheler Carina , Krampe Erhard , Foehr Peter , Haerst Miriam , Burgkart Rainer 
Published: December 2016

Abstract
In this study we characterized the wear behavior of a tribological system with material combinations of the total intervertebral disc prosthesis InDisc (Institute of Medical and Polymer Engineering) – consisting of two laser sintered titanium alloy plates with an elastomer inbetween. For the tests a translatory oscillation test bench was used which simulates the kinematic and the physiological environment of the lumbar spine. In the interface between the elastomer (Silopren LSR 2670) and the laser sintered titanium alloy (Ti6Al4V) abrasion cords out of silicone rubber with a maximal area of 500 × 700 μm2 were generated as well as individual particles with a size of 10 × 20 to 40 × 50 μm2. In the second prosthesis interface of Ti6Al4V and bone, bone particles with an area of 0.5 × 0.5 to 1 × 1 μm2 were detected. The wear particles and the amount of wear volume influence the biological response of a total intervertebral disc prosthesis in the body.
Digital health and digital biomarkers – enabling value chains on health data
Authors: Meister Sven , Deiters Wolfgang , Becker Stefan 
Published: December 2016

Abstract
Smart Devices, IoT and Co. are changing healthcare. The possibilities for pervasive sensing and analysis are fast increasing and new therapy concepts as well as business models are arising, related to the term “Digital Health”. The paper will give a brief overview on the history and ask, whether Digital Health is more than Telemedicine 4.0. Furthermore, we will ask for the prospective currency to participate in new preventive offer. Data is the new oil – Digital Biomarkers enable new value chains on health data and allow for the personalization of healthcare. We will present ongoing work of Fraunhofer ISST on a Digital Biomarker called beHealthy Health Score.
Usability in the lifecycle of medical software development
Authors: Trauzettel Franziska , Minge Michael 
Published: December 2016

Abstract
A close cooperation with users is necessary to ensure that interactive systems are robust, easy to use and accepted. Therefore, in medical technology, standards for usability are of fundamental importance. We investigated with the presented study how the concept of usability is currently understood and implemented in medical software companies. Interviews were conducted with 21 employees of German enterprises. Furthermore we extended an already existing quantitative online survey where 53 companies (including 24 from the health industry sector) participated in. Results show that the importance of usability is recognized by most of the respondents. Moreover, a wide variety of methods and approaches is known and implemented for exploring user needs and evaluating system prototypes. However, it was observed that human-centered design activities mainly focus on functionality, risk prevention and accessibility. Hedonic user needs and subjective perceptions (“user experience”) still play a minor role. Based on the results, practical requirements are derived and a “best case” for methodological approach is introduced.
Device development guided by user satisfaction survey on auricular vagus nerve stimulation
Authors: Kampusch Stefan , Kaniusas Eugenijus , Thürk Florian , Felten Dorian , Hofmann Ibolya , Széles Jozsef C. 
Published: December 2016

Abstract
Development of wearable point-of-care medical devices faces many challenges. Besides technological and clinical issues, demands on robustness, miniaturization, and user interface design are of paramount importance. However, a systematic assessment of these non-functional but essential requirements is often impossible within the first product cycle. Later, surveys on user satisfaction with existing devices and user demands can offer significant input for device re-development and improvement. In this paper, we present a survey on satisfaction with and demands for a wearable medical device for percutaneous auricular vagus nerve stimulation (pVNS). We analyzed 36 responses from patients treated with pVNS and five responses from experienced physicians in order to devise a future concept of pVNS. Main shortcomings of a current pVNS device were identified to be lacking water resistance and mechanical robustness, both impairing daily activities. Painful sensation during pVNS application, unwanted side effects like skin irritations and strongly varying perception of the stimulation were reported. Results urge for more patient self-governance and an (automatic) adjustment of the stimulation to the current physiological state of the patient. Attained results support a strategic approach for future developments of pVNS towards personalized health care.
Empirical assessment of the time course of innovation in biomedical engineering: first results of a comparative approach
Authors: Farkas Robert , Puiu Andrei Alexandru , Hamadeh Nader , Bukowski Mark , Schmitz-Rode Thomas 
Published: December 2016

Abstract
The pathway from the flash of a technological invention until its use as a medical device in every day care is tedious and burdensome. But the often postulated acceleration has to balance the speed of innovation and the indispensable product safety by an improved understanding of the innovation cycle. While several studies investigated the time course of pharmaceutical innovation, a comparable empirical analysis of medical devices is lacking. Thus we evaluated the time between the patent priority date and the corresponding receipt of the CE mark as a function of a medical device risk class in 61 cases. The statistical analysis yielded a time increment (trend) from medical devices in risk category I (median = 5.8 years) compared to risk category III (median = 10.4 years), which is close to literature reported values for drug development (9–12 years). The difference between products in risk classes I and II did not reach significance. To investigate the underlying facts, a text-mining approach especially to resolve the ambiguity of, e.g. patents, CE Marks etc. is suggested for increasing the sample size.
Assessment of nasal resistance using computational fluid dynamics
Authors: Osman Jan , Großmann Friederike , Brosien Kay , Kertzscher Ulrich , Goubergrits Leonid , Hildebrandt Thomas 
Published: December 2016

Abstract
Anterior rhinomanometry is the current gold standard for the objective assessment of nasal breathing by determining the nasal resistance. However, computational fluid dynamics would allow spatially and temporally well- resolved investigation of additional flow parameters. In this study, measured values of nasal resistance are compared with measured values. An unclear discrepancy between the two methods was found, suggesting further investigation.
Inspiratory and expiratory elastance in a non-linear autoregressive model of pulmonary mechanics
Authors: Langdon Ruby , Docherty Paul D. , Möller Knut 
Published: December 2016

Abstract
For patients with acute respiratory distress syndrome (ARDS), the use of mathematical models to determine patient-specific ventilator settings can reduce ventilator induced lung injury and improve patient outcomes. A non-linear autoregressive model of pulmonary mechanics was used to identify inspiratory and expiratory pressure-dependent elastance (Ei
and Ee
) as independent variables. The analysis was implemented on 19 data sets of recruitment manoeuvres (RMs) that were performed on 10 mechanically ventilated patients. At pressures p = 15–20 cmH2O the agreement between Ei
and Ee
was low. However, Ei
was a well-matched predictor of Ee
for p = 25–40 cmH2O, with R2 ≥ 0.78, and there was no significant bias in the difference between Ei
and Ee
. Since many other models cannot uniquely identify Ei
and Ee
, the outcome may provide further insight into the characteristics of ARDS lungs in sedated patients.
Principle study on the signal connection at transabdominal fetal pulse oximetry
Authors: Böttrich Marcel , Laqua Daniel , Husar Peter 
Published: December 2016

Abstract
Transabdominal fetal pulse oximetry is an approach to measure oxygen saturation of the unborn child non-invasively. The principle of pulse oximetry is applied to the abdomen of a pregnant woman, such that the measured signal includes both, the maternal and the fetal pulse curve. One of the major challenges is to extract the shape of the fetal pulse curve from the mixed signal for computation of the oxygen saturation. In this paper we analyze the principle kind of connection of the fetal and maternal pulse curves in the measured signal. A time varying finite element model is used to rebuild the basic measurement environment, including a bulk tissue and two independently pulsing arteries to model the fetal and maternal blood circuit. The distribution of the light fluence rate in the model is computed by applying diffusion equation. From the detectors we extracted the time dependent fluence rate and analyzed the signal regarding its components. The frequency spectra of the signals show peaks at the fetal and maternal basic frequencies. Additional signal components are visible in the spectra, indicating multiplicative coupling of the fetal and maternal pulse curves. We conclude that the underlying signal model of algorithms for robust extraction of the shape of the fetal pulse curve, have to consider additive and multiplicative signal coupling.
Evaluating different approaches to identify a three parameter gas exchange model
Authors: Kretschmer Jörn , Docherty Paul D. , Riedlinger Axel , Möller Knut 
Published: December 2016

Abstract
Mathematical models can be employed to simulate a patient’s individual physiology and can therefore be used to predict reactions to changes in the therapy. To be clinically useful, those models need to be identifiable from data available at the bedside. Gradient based methods to identify the values of the model parameters that represent the recorded data highly depend on the initial estimates. The proposed work implements a previously developed method to overcome those dependencies to identify a three parameter model of gas exchange. The proposed hierarchical method uses models of lower order related to the three parameter model to calculate valid initial estimates for the parameter identification. The presented approach was evaluated using 12 synthetic patients and compared to a traditional direct approach as well as a global search method. Results show that the direct approach is highly dependent on how well the initial estimates are selected, while the hierarchical approach was able to find correct parameter values in all tested patients.
Effects of fibrosis on the extracellular potential based on 3D reconstructions from histological sections of heart tissue
Authors: Rottmann Markus , Zürn Jannik , Arslan Ufuk , Klingel Karin , Dössel Olaf 
Published: December 2016

Abstract
Atrial fibrillation is the most common arrhythmia. However, the mechanisms of AF are not completely understood. It is known that fractionated signals are measured in AF but the etiology of fractionated signals is still not clear. The central question is to evaluate the effects of segmented fibrotic areas in histological tissue sections on the extracellular potential in a simulation study. We calculated the transmembrane voltages and extracellular potentials from the excitation wave front around a 3D fibrotic area from mouse hearts that were reconstructed from histological tissue sections. Extracellular potentials resulted in fragmented signals and differed strongly by stimulations from different directions. The transmural angle of the excitation waves had a significantly influence on the signal morphologies. We suggest for future clinical systems to implement the possibility for substrate mapping by stimulations from different directions in sinus rhythm.
From imaging to hemodynamics – how reconstruction kernels influence the blood flow predictions in intracranial aneurysms
Authors: Glaßer Sylvia , Berg Philipp , Voß Samuel , Serowy Steffen , Janiga Gabor , Preim Bernhard , Beuing Oliver 
Published: December 2016

Abstract
Computational fluid dynamics (CFD) is increasingly used by biomedical engineering groups to understand and predict the blood flow within intracranial aneurysms and support the physician during therapy planning. However, due to various simplifications, its acceptance remains limited within the medical community. To quantify the influence of the reconstruction kernels employed for reconstructing 3D images from rotational angiography data, different kernels are applied to four datasets with patient-specific intracranial aneurysms. Sharp, normal and smooth reconstructions were evaluated. Differences of the resulting 24 segmentations and the impact on the hemodynamic predictions are quantified to provide insights into the expected error ranges. A comparison of the segmentations yields strong differences regarding vessel branches and diameters. Further, sharp kernels lead to smaller ostium areas than smooth ones. Analyses of hemodynamic predictions reveal a clear time and space dependency, while mean velocity deviations range from 3.9 to 8%. The results reveal a strong influence of reconstruction kernels on geometrical aneurysm models and the subsequent hemodynamic parameters. Thus, patient-specific blood flow predictions require a carefully selected reconstruction kernel and appropriate recommendations need to be formulated.
Flow optimised design of a novel point-of-care diagnostic device for the detection of disease specific biomarkers
Authors: Dethloff Manuel , Dangers Marc , Wilmes Boris , Seitz Hermann 
Published: December 2016

Abstract
For the development of a novel, user-friendly and low cost point-of-care diagnostic device for the detection of disease specific biomarkers a flow optimised design of the test system is investigated. For this, computational fluid dynamics and rapid prototyping methods are used. The result is a functional design, which can be used for further experimental investigations.
Improved FPGA controlled artificial vascular system for plethysmographic measurements
Authors: Laqua Daniel , Brieskorn Carina , Koch Jan Hannes , Rothmayer Markus , Zeiske Steve , Böttrich Marcel , Husar Peter 
Published: December 2016

Abstract
The fetal oxygen saturation is an important parameter to determine the health status of a fetus, which is until now mostly acquired invasively. The transabdominal, fetal pulse oximetry is a promising approach to measure this non-invasively and continuously. The fetal pulse curve has to be extracted from the mixed signal of mother and fetus to determine its oxygen saturation. For this purpose efficient algorithms are necessary, which have to be evaluated under constant and reproducable test conditions. This paper presents the improved version of a phantom which can generate artificial pulse waves in a synthetic tissue phantom. The tissue phantom consists of several layers that mimic the different optical properties of the fetal and maternal tissue layers. Additionally an artificial vascular system and a dome, which mimics the bending of the belly of a pregnant woman, are incorporated. To obtain data on the pulse waves, several measurement methods are included, to help understand the behavior of the signals gained from the pulse waves. Besides pressure sensors and a transmissive method we integrated a capacitive approach, that makes use of the so called “Pin Oscillator” method. Apart from the enhancements in the tissue phantom and the measurements, we also improved the used blood substitute, which reproduces the different absorption characteristics of fetal and maternal blood. The results show that the phantom can generate pulse waves similar to the natural ones. Furthermore, the phantom represents a reference that can be used to evaluate the algorithms for transabdominal, fetal pulse oximetry.
Control scheme selection in human-machine- interfaces by analysis of activity signals
Authors: Doneit Wolfgang , Mikut Ralf , Liebetanz David , Rupp Rüdiger , Reischl Markus 
Published: December 2016

Abstract
Human-Machine Interfaces in rehabilitation engineering often use activity signals. Examples are electrical wheelchairs or prostheses controlled by means of muscle contractions. Activity signals are user-dependent and often reflect neurological weaknesses. Thus, not all users are able to operate the same control scheme in a robust manner. To avoid under- and overstraining, the interface ideally uses a control scheme which reflects the user’s control ability best. Therefore, we explored typical phenomena of activation signals. We derive criteria to quantify the user’s performance and abilities and present a routine which automatically selects and adapts one of three control schemes being best suited.
Event-based sampling for reducing communication load in realtime human motion analysis by wireless inertial sensor networks
Authors: Laidig Daniel , Trimpe Sebastian , Seel Thomas 
Published: December 2016

Abstract
We examine the usefulness of event-based sampling approaches for reducing communication in inertial-sensor-based analysis of human motion. To this end we consider realtime measurement of the knee joint angle during walking, employing a recently developed sensor fusion algorithm. We simulate the effects of different event-based sampling methods on a large set of experimental data with ground truth obtained from an external motion capture system. This results in a reduced wireless communication load at the cost of a slightly increased error in the calculated angles. The proposed methods are compared in terms of best balance of these two aspects. We show that the transmitted data can be reduced by 66% while maintaining the same level of accuracy.
Automatic pairing of inertial sensors to lower limb segments – a plug-and-play approach
Authors: Graurock David , Schauer Thomas , Seel Thomas 
Published: December 2016

Abstract
Inertial sensor networks enable realtime gait analysis for a multitude of applications. The usability of inertial measurement units (IMUs), however, is limited by several restrictions, e.g. a fixed and known sensor placement. To enhance the usability of inertial sensor networks in every-day live, we propose a method that automatically determines which sensor is attached to which segment of the lower limbs. The presented method exhibits a low computational workload, and it uses only the raw IMU data of 3 s of walking. Analyzing data from over 500 trials with healthy subjects and Parkinson’s patients yields a correct-pairing success rate of 99.8% after 3 s and 100% after 5 s.