Eemagine Medical Imaging Solutions GmbH

Berlin, Germany

Eemagine Medical Imaging Solutions GmbH

Berlin, Germany
SEARCH FILTERS
Time filter
Source Type

Rajput O.,TU Hamburg - Harburg | Antoni S.-T.,TU Hamburg - Harburg | Otte C.,TU Hamburg - Harburg | Saathoff T.,TU Hamburg - Harburg | And 2 more authors.
IEEE International Conference on Multisensor Fusion and Integration for Intelligent Systems | Year: 2017

In many clinical scenarios, the spatial resolution of typical time-of-flight devices is not sufficient. Optical coherence tomography (OCT) presents an interesting high resolution modality with applications in image guided surgery and tissue characterization. However, the small field of view makes scanning larger areas difficult. We therefore consider co-registering a ToF depth camera (Kinect) with its large field-of-view but limited accuracy and OCT with its smaller field-of-view but very high accuracy. We study two approaches to obtain a registration between Kinect and OCT. The first approach is based on a novel marker and a direct registration between the two devices, either with or without using the construction of the novel marker. The second approach uses the marker to obtain a calibration between the OCT and a hexapod (Stewart platform) carrying it, and separate calibration between hexapod and Kinect. We show that the first approach typically results in better registration between Kinect and OCT with translational and rotational errors of (2.25 ± 1.23) mm and (1.54 ± 0.77)°, respectively. Furthermore, we demonstrate the use of the combined system to obtain a high resolution scan of the irregularly shaped surface of a head phantom. © 2016 IEEE.


Fiedler P.,TU Ilmenau | Brodkorb S.,TU Ilmenau | Fonseca C.,University of Porto | Vaz F.,University of Minho | And 3 more authors.
IFMBE Proceedings | Year: 2010

Usability of conventional wet electrodes for electroencephalography (EEG) is depending on a set of requirements, including time consuming and complex preparation of the skin of a subject, thus limiting possible application. A new class of "dry" electrodes without the need for electrolyte gels or pastes is being investigated. The dry application scenario of these novel electrodes requires a stable and reliable contact with the subject's skin. In order to develop an electrode shape with large contact surface for low electrode-skin impedance while also ensuring a sufficient hair layer penetration, several studies were performed. In this paper a distinct titanium electrode substrate shape for titanium nitride (TiN) coated electrodes was analyzed regarding influences of the number of interconnected electrodes and contact surface on electrodeskin impedance and biosignal quality. As a result 10 interconnected TiN pins had the lowest impedance values of 14 to 55 kΩ (depending on signal frequency) in comparison to 2 to 44 kΩ using conventional Ag/AgCl electrodes. Also the mean average deviation (MAD) of 5 seconds long EEG episodes were computed. The lowest MADs of 2.00 to 2.25 μV were determined using three interconnected TiN pins. In comparison to MADs of 2.13 to 2.54 μV, using a second set of Ag/AgCl electrodes, this leads to the conclusion that most of the error was related to spatial distance. This first step in optimization of electrode shape for dry TiN based electrodes showed very promising results and enable their use for EEG acquisition. © 2010 International Federation for Medical and Biological Engineering.


Fiedler P.,TU Ilmenau | Pedrosa P.,University of Porto | Griebel S.,TU Ilmenau | Fonseca C.,University of Porto | And 5 more authors.
Brain Topography | Year: 2015

Current usage of electroencephalography (EEG) is limited to laboratory environments. Self-application of a multichannel wet EEG caps is practically impossible, since the application of state-of-the-art wet EEG sensors requires trained laboratory staff. We propose a novel EEG cap system with multipin dry electrodes overcoming this problem. We describe the design of a novel 24-pin dry electrode made from polyurethane and coated with Ag/AgCl. A textile cap system holds 97 of these dry electrodes. An EEG study with 20 volunteers compares the 97-channel dry EEG cap with a conventional 128-channel wet EEG cap for resting state EEG, alpha activity, eye blink artifacts and checkerboard pattern reversal visual evoked potentials. All volunteers report a good cap fit and good wearing comfort. Average impedances are below 150 kΩ for 92 out of 97 dry electrodes, enabling recording with standard EEG amplifiers. No significant differences are observed between wet and dry power spectral densities for all EEG bands. No significant differences are observed between the wet and dry global field power time courses of visual evoked potentials. The 2D interpolated topographic maps show significant differences of 3.52 and 0.44 % of the map areas for the N75 and N145 VEP components, respectively. For the P100 component, no significant differences are observed. Dry multipin electrodes integrated in a textile EEG cap overcome the principle limitations of wet electrodes, allow rapid application of EEG multichannel caps by non-trained persons, and thus enable new fields of application for multichannel EEG acquisition. © 2015, Springer Science+Business Media New York.


Fiedler P.,TU Ilmenau | Griebel S.,TU Ilmenau | Pedrosa P.,University of Porto | Pedrosa P.,University of Minho | And 7 more authors.
Sensors and Actuators, A: Physical | Year: 2014

Research using multichannel electroencephalographic recordings is increasingly characterized by greater numbers of electrodes. With up to 256 silver/silver chloride (Ag/AgCl) electrodes, preparation and electrode placement is time consuming and error prone. We propose a novel type of dry titanium/titanium nitride (Ti/TiN) electrode, integrated into a novel electroencephalography (EEG) cap based on pneumatic-driven mechanisms. The electrodes were characterized electrochemically and comparative biosignal measurements were carried out. In a NaCl solution, the impedance values were between 824 and 54 Ω and the phase values between -52 and -10° at frequencies between 5 Hz and 10 kHz for the Ti/TiN electrodes. For resting-state EEG, and with eye movements, alpha activity, and pattern reversal visual evoked potential (VEP), there were no significant differences between adjacent novel Ti/TiN and standard Ag/AgCl electrodes in 97.2% of the signal episodes investigated. The potential maps for pattern reversal VEP were similar with both types of electrodes. In conclusion, our novel cap system based on Ti/TiN electrodes and pneumatic-driven mechanisms enables completely dry EEG acquisition and can thus potentially replace conventional Ag/AgCl electrodes due to similar signal quality. © 2014 Elsevier B.V. All rights reserved.


Grant
Agency: European Commission | Branch: FP7 | Program: MC-IAPP | Phase: FP7-PEOPLE-2013-IAPP | Award Amount: 1.60M | Year: 2014

Multichannel electroencephalography (EEG) is a well-established method for investigating the function of the human brain, but, despite continuous advancements in signal amplification and data processing, difficult and error-prone signal acquisition on the head surface is still a major issue limiting its employment in basic and clinical research. The ANDREA project will develop a novel dry electrode EEG system with adjustable cap network provided with an automated sensor positioning mechanism, active preamplification and a SW toolbox for artefacts removal. The novel technologies address the requirements of high signal quality and reliability, mobility, high patient/subject comfort and long-term use, and will be validated in clinical and non clinical populations to produce a prototype optimized for broad EEG employment. To achieve these objectives, the ANDREA consortium 1) merges the complementary expertise and resources in biomedical engineering, material science, biomedical signal processing, neuroscience and clinical neurology available at 3 academic and 2 commercial (industry and health) partners from 3 EU countries, and 2) realizes an extensive intersectoral transfer of knowledge through staff exchange, training courses, schools, and the recruitment of experienced researchers with supplementary expertise from outside the consortium. The international mobility and the planned dissemination/outreach activities will contribute to the sharing of different cultures and knowledge with the scientific community, and to promote a broader communication on the importance of research in biomedical engineering to the society at large. The tight scientific collaboration and the transfer of knowledge among partners will enhance the research capacity and competitiveness of the ANDREA consortium, which will become a permanent EU research network promoting health technology in Europe, with great benefits for the European biomedical industries, health care systems and societies.


Bocquillon P.,University of Lille Nord de France | Bocquillon P.,Laboratory Neurosciences Fonctionnelles et Pathologies | Bocquillon P.,Lille University Medical Center | Bourriez J.-L.,Laboratory Neurosciences Fonctionnelles et Pathologies | And 13 more authors.
PLoS ONE | Year: 2012

Background: The selection of task-relevant information requires both the focalization of attention on the task and resistance to interference from irrelevant stimuli. Both mechanisms rely on a dorsal frontoparietal network, while focalization additionally involves a ventral frontoparietal network. The role of subcortical structures in attention is less clear, despite the fact that the striatum interacts significantly with the frontal cortex via frontostriatal loops. One means of investigating the basal ganglia's contributions to attention is to examine the features of P300 components (i.e. amplitude, latency, and generators) in patients with basal ganglia damage (such as in Parkinson's disease (PD), in which attention is often impaired). Three-stimulus oddball paradigms can be used to study distracter-elicited and target-elicited P300 subcomponents. Methodology/Principal Findings: In order to compare distracter- and target-elicited P300 components, high-density (128-channel) electroencephalograms were recorded during a three-stimulus visual oddball paradigm in 15 patients with early PD and 15 matched healthy controls. For each subject, the P300 sources were localized using standardized weighted low-resolution electromagnetic tomography (swLORETA). Comparative analyses (one-sample and two-sample t-tests) were performed using SPM5® software. The swLORETA analyses showed that PD patients displayed fewer dorsolateral prefrontal (DLPF) distracter-P300 generators but no significant differences in target-elicited P300 sources; this suggests dysfunction of the DLPF cortex when the executive frontostriatal loop is disrupted by basal ganglia damage. Conclusions/Significance: Our results suggest that the cortical attention frontoparietal networks (mainly the dorsal one) are modulated by the basal ganglia. Disruption of this network in PD impairs resistance to distracters, which results in attention disorders. © 2012 Bocquillon et al.


Bocquillon P.,University of Lille Nord de France | Bocquillon P.,Lille University Medical Center | Bourriez J.-L.,EA1046 | Bourriez J.-L.,Lille University Medical Center | And 6 more authors.
Neuroscience | Year: 2014

The N2 subcomponents of event-related potentials are known to reflect early attentional processes. The anterior N2 may reflect conflict monitoring, whereas the posterior N2 may be involved in target detection. The aim of this study was to identify the brain areas involved in the generation of the N2 subcomponents, in order to define the spatiotemporal dynamics of these attentional processes. We recorded 128-channel electroencephalograms in 15 healthy controls performing a three-stimulus visual oddball task and identified standard-, distracter- and target-elicited N2 components. Individual N2 sources were localized using standardized-weighted-low-resolution-electromagnetic-tomography (swLORETA). Comparative analyses were performed with a non-parametric permutation technique. Common N2 generators were observed in the Brodmann area (BA) 24 of the anterior cingulate cortex (ACC). The posterior cingulate cortex and the central precuneus were more involved in distracter processing, whereas the anterior precuneus and BA 32 of the ACC were target-specific. In accordance with previous demonstration of the frontoparietal cortex's critical role in attentional processes, these new data shed light on the ACC's role in conflict monitoring and its interaction with other median and frontoparietal structures in early attentional processes. © 2014 IBRO.


Ernst F.,University of Lübeck | Ernst F.,HotSwap Lubeck GmbH | Richter L.,HotSwap Lubeck GmbH | Richter L.,University of Lübeck | And 5 more authors.
International Journal of Medical Robotics and Computer Assisted Surgery | Year: 2012

Background: For many robot-assisted medical applications, it is necessary to accurately compute the relation between the robot's coordinate system and the coordinate system of a localisation or tracking device. Today, this is typically carried out using hand-eye calibration methods like those proposed by Tsai/Lenz or Daniilidis. Methods: We present a new method for simultaneous tool/flange and robot/world calibration by estimating a solution to the matrix equation AX=YB. It is computed using a least-squares approach. Because real robots and localisation are all afflicted by errors, our approach allows for non-orthogonal matrices, partially compensating for imperfect calibration of the robot or localisation device. We also introduce a new method where full robot/world and partial tool/flange calibration is possible by using localisation devices providing less than six degrees of freedom (DOFs). The methods are evaluated on simulation data and on real-world measurements from optical and magnetical tracking devices, volumetric ultrasound providing 3-DOF data, and a surface laser scanning device. We compare our methods with two classical approaches: the method by Tsai/Lenz and the method by Daniilidis. Results: In all experiments, the new algorithms outperform the classical methods in terms of translational accuracy by up to 80% and perform similarly in terms of rotational accuracy. Additionally, the methods are shown to be stable: the number of calibration stations used has far less influence on calibration quality than for the classical methods. Conclusion: Our work shows that the new method can be used for estimating the relationship between the robot's and the localisation device's coordinate systems. The new method can also be used for deficient systems providing only 3-DOF data, and it can be employed in real-time scenarios because of its speed. © 2012 John Wiley & Sons, Ltd.


Grant
Agency: European Commission | Branch: FP7 | Program: CP | Phase: ICT-2009.7.2 | Award Amount: 3.66M | Year: 2010

A lack of mobility often leads to limited participation in social life. The purpose of this STREP is to conceive a system empowering lower limbs disabled people with walking abilities that let them perform their usual daily activities in the most autonomous and natural manner. New smart dry EEG bio-sensors will be applied to enable lightweight wearable EEG caps for everyday use. Novel approaches to non-invasive BCI will be experimented in order to control a purpose-designed lower limbs orthosis enabling different types of gaits. Complementary research on EMG processing will strengthen the approach. A Virtual Reality (VR) training environment will assist the patients in generating the correct brain control signals and in properly using the orthosis. The main BCI approach relies on Dynamic Recurrent Neural Network (DRNN) technology applied in a two stages process. After learning, the system will be able to match EMG signals to legs movements (Stage 2), and EEG to such EMG signals (Stage 1). The Stage 2 has already been successfully demonstrated by a project partner. The orthosis will be designed to support the weight of an adult, to address the dynamic stability of a body-exoskeleton combined system, and to enable different walking modalities. The VR training environment will comprise both a set of components for the progressive patient training under a safe and controlled medical environment, and a lightweight portable set using immersive VR solutions for self-training at home. The developed technologies will be assessed and validated with the support of a formal clinical validation procedure. This will allow to measure the strengths and weaknesses of the chosen approaches and to identify improvements required to build a future commercial system. In addition the resulting system will be progressively tested in everyday life environments and situations, ranging from simple activities at home to eventually shopping and interacting with people in the street.


PubMed | University of Lille Nord de France, Lille University Medical Center and Eemagine Medical Imaging Solutions GmbH
Type: | Journal: Neuroscience | Year: 2014

The N2 subcomponents of event-related potentials are known to reflect early attentional processes. The anterior N2 may reflect conflict monitoring, whereas the posterior N2 may be involved in target detection. The aim of this study was to identify the brain areas involved in the generation of the N2 subcomponents, in order to define the spatiotemporal dynamics of these attentional processes. We recorded 128-channel electroencephalograms in 15 healthy controls performing a three-stimulus visual oddball task and identified standard-, distracter- and target-elicited N2 components. Individual N2 sources were localized using standardized-weighted-low-resolution-electromagnetic-tomography (swLORETA). Comparative analyses were performed with a non-parametric permutation technique. Common N2 generators were observed in the Brodmann area (BA) 24 of the anterior cingulate cortex (ACC). The posterior cingulate cortex and the central precuneus were more involved in distracter processing, whereas the anterior precuneus and BA 32 of the ACC were target-specific. In accordance with previous demonstration of the frontoparietal cortexs critical role in attentional processes, these new data shed light on the ACCs role in conflict monitoring and its interaction with other median and frontoparietal structures in early attentional processes.

Loading Eemagine Medical Imaging Solutions GmbH collaborators
Loading Eemagine Medical Imaging Solutions GmbH collaborators