bluuebunny/crossref_metadata_2025_split huggingface dataset:
Audio-based tissue classification - preliminary investigation for a needle procedure
Authors: Serwatka Witold , Heryan Katarzyna , Sorysz Joanna , Illanes Alfredo , Boese Axel , Krombach Gabrielle A. , Friebe Michael 
Published: September 2023

Abstract
Image-guided and minimally invasive procedures still require confirmation on having reached a target. Intraoperative imaging is not always sufficient or conclusive as it comes with artifacts that can come with a certain amount of ambiguity and inaccurate location information. As an alternative to imaging, we want to explore sounds produced by the biopsy needle tip while advancing and interacting with tissue. In this paper, we show that by analyzing vibroacoustic signals acquired at the proximal end of the needle we are able to differentiate the tissue type. In total, 419 audio samples of 5 tissues were acquired and converted to spectrograms used as input to a convolutional neural network. Using this experimental setup we were able to differentiate the tissue types with an F1 score of 71.64%. Based on these results we were able to demonstrate the feasibility of our approach, as well as the importance of further experiments to ensure that vibroacoustic sounds produced by the needle tip can be a new navigation method.
Optimization Techniques for Semi-Automated 3D Rigid Registration in Multimodal Image-Guided Deep Brain Stimulation
Authors: Al-Jaberi Fadil , Fachet Melanie , Moeskes Matthias , Skalej Martin , Hoeschen Christoph 
Published: September 2023

Abstract
Multimodal image registration is vital in Deep Brain Stimulation (DBS) surgery. DBS treats movement disorders by implanting a neurostimulator device in the brain to deliver electrical impulses. Image registration between computed tomography (CT) and cone beam computed tomography (CBCT) involves fusing images with a specific field of view (FOV) to visualize individual electrode contacts. This contains important information about the location of segmented contacts that can reduce the time required for electrode programming. We performed a semi-automated multimodal image registration with different FOV between CT and CBCT images due to the tiny structures of segmented electrode contacts that necessitate high accuracy in the registration. In this work, we present an optimization workflow for multi-modal image registration using a combination of different similarity metrics, interpolators, and optimizers. Optimization-based rigid image registration (RIR) is a common method for registering images. The selection of appropriate interpolators and similarity metrics is crucial for the success of this optimization-based image registration process.We rely on quantitative measures to compare their performance. Registration was performed on CT and CBCT images for DBS datasets with an image registration algorithm written in Python using the Insight Segmentation and Registration Toolkit (ITK). Several combinations of similarity metrics and interpolators were used, including mean square difference (MSD), mutual information (MI), correlation and nearest neighbors (NN), linear (LI), and B-Spline (SPI), respectively. The combination of a correlation as similarity metric, B-Spline interpolation, and GD optimizer performs the best in optimizing the 3D RIR algorithm, enhancing the visualization of segmented electrode contacts. Patients undergoing DBS therapy may ultimately benefit from this.
Using adaptive learning rate to generate adversarial images
Authors: Ding Ning , Möller Knut 
Published: September 2023

Abstract
Convolutional neural networks (CNNs) have proved their efficiency in performing image classification tasks, as they can automatically extract the image features and make the corresponding prediction. Meanwhile, the CNNs application is highly challenged by their vulnerability to adversarial samples. These samples are slightly different from the legitimate samples, but the CNN gives wrong classification. There are various ways to find the adversarial samples. The most common method is using backpropagation to generate gradients as the directed perturbation. Contrarily to set a constrained limitation, in this paper, we use iterative fast gradient sign method to generate adversarial images with the minimum perturbation. The CNNs were trained to perform surgical tool recognition as a configuration for the modern operation room. The coefficient or the learning rate which influenced the modification per iteration, was set to be adaptive instead of a fixed number. A few functions were utilized to perform the learning rate decay to compare the performance. Especially, we propose a new adaptive learning rate algorithm that consider the loss as a part of influence factor constitute the learning rate for the rest iterations. According to the experiments, our loss adaptive learning rate method was proved to be efficient to get the minimal perturbations for adversarial attack.
Fabrication and characterization of flexible microelectrode arrays for the long-term recording of mammalian brain slices
Authors: Frese Hanna , Kauth Andrea , Koch Henner , Ort Jonas , Ingebrandt Sven 
Published: September 2023

Abstract
A profound understanding of brain disorders is essential for developing more effective treatments, targeted therapies, and reliable diagnoses. Electrical in vitro long-term and repetitive measurements give insight to neural activity of more complex neural circuits and, thus, into malfunctioning caused by illness. Flexible microelectrode arrays (flexMEAs) enable the recording of neural activity with promising spatial and temporal resolution over longer durations. The present study aims to combine the long-term recording by flexMEAs with the cultivation of brain slices inside an incubator. An 8 μm-thin flexMEA with up to 256 electrodes with 30 μm in diameter and interelectrode spacing of 200 μm was fabricated. Characterization showed uniform and reproducible electronic characteristics. Coating with PEDOT:PSS by electropolymerization formed stable low-impedance spectra. The platform is ready for future experiments with brain slices inside an incubator.
Biphasic parameter determination of sheep articular cartilage from stress relaxation data using an optimized 3D FE-based method
Authors: Reuter Thomas , Horbert Victoria , Kinne Raimund , Hurschler Christof 
Published: September 2023

Abstract
Mechanical characteristics of hard and soft tissues are central features for the quantitative description of tissue properties. In this study, we present a biphasic 3D-FE-based method to determine the biomechanical properties of sheep stifle joint articular cartilage (load-bearing area of the medial and lateral femur condyle, n = 28) from stress relaxation indentation tests (s = 0.1 mm, t = 180 s). The FE-model computation was optimized by exploiting the axial symmetry and mesh resolution. Parameters were determined using the Levenberg-Marquardt-algorithm. Results showed significant differences between the biomechanical parameters of the lateral (n = 11) and medial (n = 17) femur condyle of the sheep stifle joint articular cartilage. R² of the fit results varied between 0.91 and 0.99. Overall values for the Young’s modulus were 1.316 ± 0.778 MPa, for the Poisson’s ratio 0.106 ± 0.088 and for the permeability 0.008 ± 0.004 mm4/Ns. Future work will focus on studying the influence of experimental settings on the results obtained with the biphasic 3D-FE-model.
Fast 4D FEM Model for EIT Source Separation Benchmarking
Authors: Silva Diogo Filipe , Leonhardt Steffen 
Published: September 2023

Abstract
The accurate separation of cardiac and ventilatory contributions to electrical impedance tomography signals is crucial for complete and non-invasive cardiorespiratory monitoring. However, no consensus on a suitable source separation algorithm was achieved despite several proposals due to lacking systematic evaluation. To address this, we propose a benchmarking 4D finite element method generative model for mixed, cardiac, and ventilatory signals. Our model implements dynamic modelling of the heart, lungs, and pulmonary arteries using realistic volume and flow curve templates, along with cardiac and respiratory frequency coupling.We also employed variable alveolar and blood conductivities. The model was able to obtain long recordings faster than comparably complex models while maintaining significant physiological effects and signal properties such as non-stationarity, spatial delays, time and frequency profiles. The realistic physiological model can be used to taxonomize and evaluate source separation algorithms, as well as aid in the development and training of new ones.
Diagnostic medical device for stabilized image perception of retinal blood vessels using entoptic phenomena
Authors: Tautorat Carsten , Lebahn Kerstin , Schmidt Wolfram , Guthoff Rudolf , Stahnke Thomas , Lips Thomas , Grabow Niels 
Published: September 2023

Abstract
A diagnostic medical tool is described that allows patients to non-invasively observe, describe and document their own retinal blood vessels using the Purkinje vascular entoptic test. We envision key applications of the Purkinje retinal image stabilization (PRIS) device in monitoring of diabetic retinopathy and cost-effective assessment of retinal visual acuity. To optimize our PRIS principle, we have developed a benchtop device with interchangeable light modules. The modular design is intended to provide maximum flexibility for determining appropriate PRIS stimulation parameters. In self-tests, we found that a pleasant entoptic perception occurs when a green luminous light spot (approx. 525 nm) moves on a circular path. The challenging part is to derive an objective diagnosis from a subjective phenomenon.
Accuracy of CT numbers and electron density calibration for mixtures of materials with low and high-atomic number
Authors: Ese Zehra , Erni Daniel , Zylka Waldemar 
Published: September 2023

Abstract
In computed tomography (CT) materials with high-atomic number Z cause image artefacts, thus, errors in CT numbers given in Hounsfield Units (HU). Also, the conventional HU scale (CHU) implemented in CT scanners is truncated, i.e., it does not cover high-Z materials. These restrictions lead to incorrect mapping of CT numbers to electron density, which are used in radiotherapy (RT) treatment planning systems (TPS). Even analytical conversion methods are only permissible for tissue-equivalent materials. In terms of HU-to-density conversion in RT TPS, we investigated the CT numbers of material mixtures up to Z<29 at the CHU and an extended-HU (EHU) scale, respectively, and quantify the systematic errors of image artefacts. In [1] the feasibility of a stoichiometric analytical calibration method were analyzed for metals and adapted for higher accurcy, for energies of 80 kV and 120 kV. In this work, we add results for 100 kV and 140 kV to cover the wide diagnostic range. The CT numbers are effected by physical and machine-based properties and depend strongly on the energy, e.g., for Cu a HU difference of 6 171HU at 80 kV and 140 kV occured. The analytical calibration parameters change with energy by a factor between 2 and 10 depending on the physical process. Although for high- Z materials our calibration procedure remains in conflict with rigorous physics [2], it offers an improved and a practical way to predict electron densities from CT numbers.
Development of quality criteria for long-term testing of intracortical electrodes
Authors: Sielaff Charlotte , Urban Ute , Froriep Ulrich P. 
Published: September 2023

Abstract
The use of intracortical electrodes is a crucial method for medical diagnosis and treatment and holds the promise for overcoming various neural diseases and challenges in prosthetics. The general physical and electrical function as well as the biocompatibility is extensively tested before intracortical electrodes are implanted, however, their longterm performance, is still limited through tissue scarring and electrode deterioration, and consequently a decrease in signal quality. To overcome this challenge, aspects such as materials selection, coatings, flexibility, and surgical procedures are often addressed. To date, however, a systematic, industry - compatible process for long-term functional testing of new intracortical electrodes technologies is still lacking. Implementation of a general overall in vivo testing procedure with defined quality criteria would enable reliable in vivo longterm (> 30 days) device assessment. This could reduce the risk in developing probes for long-term performance and pave the way for clinical application in patients suffering from neural diseases.
Analyzing the Effect of Age and Gender on the Blink Reflex using MediaPipe
Authors: Güney Gökhan , Jansen Talisa S. , Braczynski Anne K. , Rohr Maurice , Dill Sebastian , Hoog Antink Christoph 
Published: September 2023

Abstract
The glabellar tapping reflex (GTR) is a sign related to brain conditions and can be analyzed by clinicians for diagnostic purposes. To facilitate the quantitative analysis of this reflex, we developed a video-based tool using the MediaPipe framework. We tested our approach on healthy subjects to assess the effect of age and gender on reaction time and blinking duration. The reaction time results show that the young group has a mean value (±standard deviation) of 0.091 (±0.066) seconds and the old group has 0.085 (±0.052) seconds, while female and male subjects have 0.097 (±0.053) seconds and 0.080 (±0.064) seconds respectively. For blinking duration, males have a mean value of 0.216 (±0.077) seconds and, females have 0.189 (±0.115) seconds, while old and young groups have 0.132 (±0.039) seconds 0.267(±0.084) seconds respectively.
Defibrillation data analysis of prehospital resuscitation scenarios having different impulse durations
Authors: Fischer Jonas , Wenzel Folker 
Published: September 2023

Abstract
The objective of this study was to assess and present technical data related to resuscitation procedures that involved the application of a defibrillator for at least one shock. Specifically, we sought to distinguish two rectangular defibrillation impulses in terms of varying phase durations. The evaluation encompassed a range of defibrillation metrics and metadata, including transthoracic impedance, mean and peak currents. The results of this analysis provide valuable insights into the technical aspects of defibrillation.
Computer-assisted generation of anaesthesia report during laparoscopic procedures
Authors: Aldeen Jalal Nour , Abdulbaki Alshirbaji Tamer , Laufer Bernhard , Docherty Paul D. , Neumuth Thomas , Moeller Knut 
Published: September 2023

Abstract
Automatic generation of intraoperative anaesthesia reports has great potential to generate accurate and efficient documentation and allow the anaesthesiologists to utilise their time more optimally. However, automatically generating anaesthesia reports represents a demanding component in future operating rooms. In this paper, a computer-assisted system for anaesthesiology report generation during laparoscopic surgery is proposed. Data from anaesthesia machine, patient monitor, and surgical devices were acquired and analysed. The system proved to generate more accurate, efficient, and better readable reports compared to hand-written ones by clinicians. Moreover, additional information that describes surgical activities and events was also added by analysing surgical data.
Symmetry of Respiration Induced Upper Body Movements
Authors: Laufer Bernhard , Krueger-Ziolek Sabine , Aldeen Jalal Nour , Docherty Paul D. , Hoeflinger Fabian , Reindl Leonhard , Moeller Knut 
Published: September 2023

Abstract
Many researchers have postulated inexpensive methods to estimate respiratory volumes from respirationinduced movements of the upper body. In the development of smart garments, the number and the optimal positioning of sensors is an essential aspect. Therefore, the symmetry of upper body respiratory movements was investigated based on the measurement data from a motion capture system. In the ventral central area, coefficients of determination above 0.99 regarding movements of symmetrical markers mean that sensors can be placed without restrictions in the position mirrored on the sagittal plane. This simplifies sensor positioning in a smart shirt and expands the range of applications of smart shirts for respiratory monitoring.
Randomized Registry Trials - efficient post market clinical follow-up for medical devices
Authors: Leuchter Matthias , Siewert Stefan , Stiehm Michael , Klar Ernst , Schmitz Klaus-Peter , Kaule Sebastian 
Published: September 2023

Abstract
In spite of advances in the treatment of cardiovascular disease, there remains a significant need for high-quality evidence for clinical practice given the rising prevalence worldwide. Next to the increase of regulatory requirements, poor screening-to-recruitment ratios, lack of patient engagement, and long timelines for contracting and institutional review board (IRB) approval are leading to an outflow of clinical trials in the EU. Patient registries are a potentially rich source of data, especially for evaluating the course of rare diseases and effects of new treatments. In the sectors of regulatory assessments of medical devices they are greatly underused. Health-related real world data provide crucial support for regulatory decision-making, particularly post-market assessments of medical products. Registries can be used not only for observational studies, but also for conducting experimental study designs. Register-based randomized controlled trials (RRCTs) are of particular importance here, as they can combine the advantages of randomized controlled trials (RCT) and registers. The government's financial support and reduction of regulatory barriers to the implementation of registry-based RCT are incentive factors for manufacturers to let their medical devices (re-)certified. Furthermore, it is essential that the necessary criteria are already taken into account when setting up the German implant registry in order to enable future RRCTs. The presented work is an additional pleading for the use and extension of registries for all medical products.
Post-modification of PLLA nanofiber nonwovens by various solvent treatments
Authors: Götz Andreas , Reske Thomas , Oschatz Stefan , Grabow Niels , Illner Sabine 
Published: September 2023

Abstract
Degradable polymeric Biomaterials, such as polylactic acid, are widely used in medical field as bioresorbable implant coatings. More recently, stent covers, implantable tubes or wound dressings made from electrospun nanofibers have been developed. In order to tailor the material for specific applications, dedicated fine-tuning procedures are required. To modify fiber interconnection or porosity, solvents or their dilutions are applicable. In this work, the effect of differently diluted protic and aprotic-polar solvents on electrospun poly-L-lactic acid (PLLA) nonwovens was investigated via immersion or vapor exposure. Fiber adhesion was observed with protic solvents. Fiber destruction and increased polymer crystallinity was observed with aprotic polar solvents. The immersion duration revealed to be far more irrelevant than solvent dilution. None of the tested solvents affected molecular weight. This opens up significant research potential to replace halogenated solvents as a cornerstone of eco-friendly “green” electrospinning processes. The results of this study are suggesting that biomaterials with desired properties can be produced in a targeted manner.
Non-invasive glucose sensing via the fingernail bed using THz radiation
Authors: Jalali Mandana , Prokscha Andreas , Yan Yijun , Kubiczek Tobias , Taro Svejda Jan , Preu Sascha , Balzer Jan , Kaiser Thomas , Erni Daniel 
Published: September 2023

Abstract
The possibility of establishing a novel technique for reliably accessing glycemic information in a non-invasive, easy to implement method at THz frequencies via the fingernail bed is investigated. The nail bed’s major content is blood at its various glucose levels and is also partially protected from environmental conditions by the nail plate, making it a desirable platform for non-invasive glucose sensing. The study is based on a 2D computational electromagnetics (EM) model of the layered fingernail in COMSOL Multiphysics, where the required dielectric function (i.e. permittivity and conductivity) of the fingernail plate is measured using THz-Time-Domain- Spectroscopy (THz-TDS), and the glucose-dependend dielectric functions of the fingernail bed are taken from available experimental data in the literature. From this data a material model using a multipole Cole-Cole model is established for both, the nail plate and the nail bed, where the glucose content in the latter is varied from 3.0-19.0 mmol/l. A numerical analysis of the THz reflectometry at the fingernail in the frequency range of 0.1-2.0 THz revealed that the reflectance spectra are sensitive to the glucose content in the nail bed proving that accurate glucose sensing via the fingernail bed may become feasible around 0.2-0.4 THz.
Telemonitoring – Regulations and Opportunities
Authors: Ikar Faduma , Bui Jessica , Musse Nafisa , Hahn Kai , Brück Rainer , Keil Alexander 
Published: September 2023

Abstract
Regulation compliance, privacy, and security issues all need to be taken into consideration while using remote patient monitoring. This article on current developments in remote healthcare and monitoring sheds light on contactless techniques and draws attention to the difficulties still facing the deployment of remote patient monitoring. It is summarized how remote patient monitoring is already being used, paying special attention to Germany and its regulatory framework.
Smartphone-Based Videonystagmography Using Artificial Intelligence
Authors: Reinhardt Sophia , Schmidt Joshua , Schneider Jonas , Schulte Elena , Schüle Christiane , Leuschel Michael , Schipper Jörg 
Published: September 2023

Abstract
Dizziness is a common symptom in medicine. The anamnesis and detection of a nystagmus is essential to distinguish a vertigo's pathogenesis. The diagnosis is complex, expensive, and not always available across the board. We present a novel location- and time-independent mobile application for videonystagmography (VNG) to support vertigo patients and medical staff. No additional hardware is necessary. The app uses artificial intelligence for eye tracking and to detect a horizontal nystagmus. A feasibility study of the mobile VNG with 13 healthy volunteers was performed. Each participant underwent a caloric vestibular testing to provoke the presence of a vestibular nystagmus. It could be shown that a smartphone-based VNG is possible.
Multifrequency bioimpedance device based on the Analog Discovery 2: performance and characterization
Authors: Battistel Alberto , Craamer Lizarraga Hegoa , Termenon Maite , Möller Knut 
Published: September 2023

Abstract
Bioimpedance spectroscopy can be used to investigate the composition and monitor the human body, organs, tissues, or cell cultures by measuring the voltage developed by the injection of small alternating currents at different frequencies. These currents are injected sequentially through a frequency sweep and a with a Howland current source or one of its modifications. However, the frequency sweep is not time efficient and introduces problems with data coherence in the case of bioinstability. On the other hand, the Howland current source requires high precision matching between its components. In this contribution we developed a custom-made device for bioimpedance measurements based on a multisine current waveform and on a negative-feedback topology for the current source. Measurements on passive elements showed that the device had less than 1Ω and 0.05∘ uncertainty in the frequency range between 500 Hz and 200 kHz for impedance between 1 kΩ and 10 kΩ. The measurements were affected by an inductive artifact connected with the limited common-mode rejection at high frequencies. Nevertheless, we could characterize the artifacts through a fitting procedure to recover the expected value of the targeted impedance.