Abstract
New implants for vascular therapy like flow diverters are made of tiny braided wires. The radio opacity of these wires is poor, which makes assessment of implant expansion and exact positioning difficult. Additional markers only allow the estimation of the current device position, but they also induce artefacts that impair the assessment during the intervention and in follow-up examination. A new strategy to increase implant visibility is the braiding of composite wires with a radiopaque core along the whole implant. This paper shows some useful combinations of these new wires on a phantom study with five vascular implants.
1 Introduction
Radiographic visibility of vascular implants is a major requirement beside the mechanical performance [1]. New implants like flow diverters (FD) are made of braided small NITINOL wires [2]. Due to the thin material, the radio opacity of these devices is poor [3]. To enhance visibility, radiopaque markers made of gold, platinum, or tantalum are integrated in current implants [4]. A new approach is the use of wires produced by “Drawn Filled Tubing” (DFT) (Fort Wayne Metals, Fort Wayne, USA). We investigated the change in visibility of different variants of implants made of DFT wires compared to a state of the art FD in a phantom study.
2 Methods
A proper phantom for the visibility studies was created based on experience und preliminary work of our group [5–9]. A model of a human skull was filled with gelatine containing a small amount of contrast agent (CA) (Imeron 350, Bracco imaging, Konstanz, Germany) to imitate bone structures and soft tissue. A shrinking tube in a bended shape was placed in the gelatine as a model of the internal carotid artery. For the evaluation, five variants of FD where produced (Acandis GmbH & Co KG, Pforzheim, Germany). Four of the FD were partially or completely made of DFT wires. For fabrication of DFT wires a core of one metal, e.g. platinum, is placed in a tube of another metal, e.g. NITINOL. After thinning by pultrusion the material combination is fixed together [10]. The following variants of implants were used for visibility testing:
. FD state of the art (SoA) made out of 40 NITINOL wires, two platinum wires and end markers
. FD DFT 50 (50% of the wires (24pc) DFT: NITINOL wire with platinum core 70%/30%) and end markers
. FD DFT 100 (100% of the wires (48pc) DFT: NITINOL wire with platinum core 70%/30%) and end markers
. FD DFT 50 10 (50% of the wires (24pc) DFT: NITINOL wire with platinum core 90%/10%), no markers
. FD DFT 100 10 (100% of the wires (48pc) DFT: NITINOL wire with platinum core 90%/10%), no markers
The implants where successively placed in the shrinking tube of the phantom under image guidance. To simulate a venous contrast injection the tube was filled with water first and flushed with a water CA mix (7%) afterwards. The phantom including the device was imaged with two different angiographic c-arm systems (Artis zeego, Artis Q, both SIEMENS Healthcare, Forchheim, Germany) under 2D fluoroscopic mode, 2D radiography, standard 3D cone beam CT and 3D cone beam CT micro (only Artis Q). The imaging setup is shown in Figure 1.
The 3D cone beam CT micro is a scan mode with a small volume of interest but a high resolution due to a 1x1 binning of the detector [11]. The scan parameters of all image protocols are shown in Table 1.
Scan parameters off the performed imaging protocols
Image System | 2D fluoro-scopy | 2D radio-graphy | 3D cone beam CT (micro) | |
---|---|---|---|---|
Artis zeego | Voltage | 76 KV | 102 KV | 80 KV |
Current | 242 mA | 395 mA | 252 mA | |
Zoom | 11 cm | 11 cm | 48 cm | |
Frames | 498 | |||
Artis Q | Voltage | 65 KV | 70 KV | 112 KV |
Current | 95 mA | 400 mA | 270 mA | |
Zoom | 11 cm | 11 cm | 22 cm | |
Frames | 498 |

Imaging setup with skull phantom on the Artis zeego
The resulting images of both systems, all image protocols and of the different implants where prepared for comparison. For 2D images lateral views with the skull base and soft tissue overlaying the implant were acquired. For 3D imaging a slice in the center line view of the implant was chosen. These images where compared with respect to their visibility in 2D and 3D images (Figure 2, 3, 4).

Fluoroscopic images of the implants in a phantom model.

Radiography of the implants in a phantom model

3D cone beam CT micro images of the scanned implants in a phantom model (voxel size 0,118)
3 Results
Comparing both imaging systems, a marked increase in spatial resolution can be stated with the new Artis Q, especially in the 3D micro mode. Regarding the visualisation of the FD, the marker of the SoA FD are proper visible in 2D imaging, whereas an impression of the 3D location is hard to get. In 3D imaging the platinum wires cause artefacts, which limit the assessment of the wall apposition or complete opening. DFT wires generally leads to a nearly homogenous appearance of the device. The DFT 50, DFT 100 and DFT 100 10 are well depicted with fluoroscopy and radiography, but the visibility of the DFT 50 10 is very poor in 2D. Reasons for this are the lack of markers and the low amount of platinum inside the wires. With 3D imaging, all variants showed good results. The DFT 100 causes minor artefacts, but these don’t have an impact on the estimation of the wall apposition. The contrast ratio (C) was calculated between the implant corpus (I) and bone structure (B) or soft tissue (S) and between implant marker (M) and bone structure or soft tissue.
Evaluation of contrast ratio (C) of the implant corpus (I) and bone structure (B) or soft tissue (S) and between implant marker (M) and bone structure or soft tissue
Artis zeego | SoA FD | DFT 100 | DFT 50 | DFT 100 10 | DFT 50 10 | ||
---|---|---|---|---|---|---|---|
FL | |||||||
I | B | 0.361 | 0.311 | 0.427 | 0.517 | 0.169 | |
S | 0.050 | 0.094 | 0.033 | 0.030 | 0.098 | ||
M | B | 0.426 | 0.295 | 0.395 | |||
S | 0.027 | 0.111 | 0.072 | ||||
DR | |||||||
I | B | 0.260 | 0.434 | 0.363 | 0.302 | 0.188 | |
S | 0.008 | 0.055 | 0.010 | 0.030 | 0.014 | ||
M | B | 0.205 | 0.410 | 0.356 | |||
S | 0.066 | 0.085 | 0.019 | ||||
3D | |||||||
I | B | 0.092 | 0.255 | 0.003 | 0.265 | 0.104 | |
S | 0.920 | 0.976 | 0.995 | 0.973 | 0.911 | ||
M | B | 0.332 | 0.482 | 0.371 | |||
S | 0.951 | 0.986 | 0.998 | ||||
Artis Q | SoA FD | DFT 100 | DFT 50 | DFT 100 10 | DFT 50 10 | ||
FL | |||||||
I | B | 0.505 | 0.280 | 0.264 | 0.321 | 0.200 | |
S | 0.035 | 0.062 | 0.014 | 0.038 | 0.058 | ||
M | B | 0.485 | 0.260 | 0.241 | |||
S | 0.062 | 0.083 | 0.038 | ||||
DR | |||||||
I | B | 0.396 | 0.414 | 0.243 | 0.384 | 0.242 | |
S | 0.030 | 0.091 | 0.037 | 0.053 | 0.062 | ||
M | B | 0.386 | 0.370 | 0.237 | |||
S | 0.042 | 0.143 | 0.044 | ||||
3D micro | |||||||
I | B | 0.160 | 0.678 | 0.206 | 0.554 | 0.002 | |
S | 0.952 | 0.986 | 0.977 | 0.971 | 0.942 | ||
M | B | 0,496 | 0,922 | 0,788 | |||
S | 1.023 | 1.003 | 0.996 |
C: Contrast ratio HC: High contrast structure LC: Low contrast structure
The numerical evaluation is shown in Table 2 for all implants and both imaging systems.
4 Conclusion
For an increase of visibility of thin wire implants a new strategy is the use of DFT wires. The experiments showed a good correlation between percentage of DFT and visibility. Important for a sufficient representation in 2D and 3D imaging is the percentage of platinum. Larger amounts of platinum increase the visibility in 2D imaging, but artefacts in 3D imaging are more pronounced. In this regard, a good compromise was shown for both FD designs DFT 50 and DFT 100 10. Moreover, influence of wire composition on mechanical performance should also be considered for final implant design.
Acknowledgement
The work of this paper is partly funded by the Federal Ministry of Education and Research within the Forschungscampus STIMULATE under grant number ’13GW0095A’ and INKA (03IPT7100X).
Author's Statement
Conflict of interest: Authors state no conflict of interest. Material and Methods: Informed consent: Informed consent has been obtained from all individuals included in this study. Ethical approval: The research related to human use has been complied with all the relevant national regulations, institutional policies and in accordance the tenets of the Helsinki Declaration, and has been approved by the authors’ institutional review board or equivalent committee.
References
[1] J. Wiskirchen, K. Kraemer, C. König, U. Kramer, J. Trübenbach, A. Wersebe, G. Tepe, K. Dietz, C. D. Claussen, and S. H. Duda, “Radiopacity of current endovascular stents: evaluation in a multiple reader phantom study,” J. Vasc. Interv. Radiol. JVIR, vol. 15, no. 8, pp. 843–852, Aug. 2004.10.1097/01.RVI.0000136985.06722.ADSuche in Google Scholar PubMed
[2] J. Ma, Z. You, J. Byrne, and R. R. Rizkallah, “Design and Mechanical Properties of a Novel Cerebral Flow Diverter Stent,” Ann. Biomed. Eng., vol. 42, no. 5, pp. 960–970, Jan. 2014.10.1007/s10439-013-0967-3Suche in Google Scholar PubMed
[3] A. Simgen, D. Ley, C. Roth, U. Yilmaz, H. Körner, R. Mühl-Benninghaus, Y.-J. Kim, B. Scheller, and W. Reith, “Evaluation of a newly designed flow diverter for the treatment of intracranial aneurysms in an elastase-induced aneurysm model, in New Zealand white rabbits,” Neuroradiology, vol. 56, no. 2, pp. 129–137, Nov. 2013.10.1007/s00234-013-1296-9Suche in Google Scholar PubMed
[4] J. Wiskirchen, R. Venugopalan, A. D. Holton, C. König, U. Kramer, J. Trübenbach, G. Tepe, C. D. Claussen, and S. H. Duda, “Radiopaque markers in endovascular stents–benefit and potential hazards,” RöFo Fortschritte Auf Dem Geb. Röntgenstrahlen Nukl., vol. 175, no. 4, pp. 484–488, Apr. 2003.10.1055/s-2003-38439Suche in Google Scholar PubMed
[5] T. Hoffmann, S. Glaßer, F. Klink, A. Boese, and M. Skalej, “Development of vessel phantoms using intravascular ultrasound (IVUS) datasets,” in Biomed Tech 2014, Hannover, Germany, 2014, vol. 59, p. 893.Suche in Google Scholar
[6] F. Klink, T. Hoffmann, A. Boese, M. Skalej, and K.-H. Grote, “Additive Manufacturing of Anatomival Phantoms Based on Medical Imaging Data Sets,” presented at the 3rd International Conference on Design Engineering and Science (ICDES 2014), Pilsen, 2014.Suche in Google Scholar
[7] A. Boese, S. Gugel, S. Serowy, J. Purmann, G. Rose, O. Beuing, M. Skalej, Y. Kyriakou, and Y. Deuerling-Zheng, “Performance evaluation of a C-Arm CT perfusion phantom,” Int. J. Comput. Assist. Radiol. Surg., Dec. 2012.10.1007/s11548-012-0804-4Suche in Google Scholar PubMed
[8] J. Krug, K. Jungnickel, M. Kaiser, J. Ricke, G. Rose, and A. Boese, “Investigating the Artifacts of Different Rapid Prototyping Materials under MR,” Proc. 9th Inteventional MRI Symp., vol. 9, p. 130, 2012.Suche in Google Scholar
[9] A. Boese, A. Fahlberg, and G. Rose, “Rapid Prototyping Phantom der arteriellen Gefäße des Kopfes,” in 10. Magdeburger Maschinenbau-Tage, Forschung und Innovation, Magdeburg, 2011.Suche in Google Scholar
[10] Medical Device Materials VI: Proceedings from the Materials and Processes for Medical Devices Conference: (MPMD 2011) . ASM International, 2013.Suche in Google Scholar
[11] O. Riabikin, S. Serowy, D. Rostalski, U. Vorwerk, A. Boese, S. Gugel, H. Paukisch, E. Eppler, O. Beuing, T. Redel, Y. Kyriakou, and M. Skalej, “Improved imaging of temporal bone anatomy by high resolution ct using a flat panel detector system,” presented at the 109th Annual Meeting of the Anatomische Gesellschaft, Salzburg, 2014.Suche in Google Scholar
© 2015 by Walter de Gruyter GmbH, Berlin/Boston
This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Artikel in diesem Heft
- Research Article
- Development and characterization of superparamagnetic coatings
- Research Article
- The development of an experimental setup to measure acousto-electric interaction signal
- Research Article
- Stability analysis of ferrofluids
- Research Article
- Investigation of endothelial growth using a sensors-integrated microfluidic system to simulate physiological barriers
- Research Article
- Energy harvesting for active implants: powering a ruminal pH-monitoring system
- Research Article
- New type of fluxgate magnetometer for the heart’s magnetic fields detection
- Research Article
- Field mapping of ballistic pressure pulse sources
- Research Article
- Development of a new homecare sleep monitor using body sounds and motion tracking
- Research Article
- Noise properties of textile, capacitive EEG electrodes
- Research Article
- Detecting phase singularities and rotor center trajectories based on the Hilbert transform of intraatrial electrograms in an atrial voxel model
- Research Article
- Spike sorting: the overlapping spikes challenge
- Research Article
- Separating the effect of respiration from the heart rate variability for cases of constant harmonic breathing
- Research Article
- Locating regions of arrhythmogenic substrate by analyzing the duration of triggered atrial activities
- Research Article
- Combining different ECG derived respiration tracking methods to create an optimal reconstruction of the breathing pattern
- Research Article
- Atrial and ventricular signal averaging electrocardiography in pacemaker and cardiac resynchronization therapy
- Research Article
- Estimation of a respiratory signal from a single-lead ECG using the 4th order central moments
- Research Article
- Compressed sensing of multi-lead ECG signals by compressive multiplexing
- Research Article
- Heart rate monitoring in ultra-high-field MRI using frequency information obtained from video signals of the human skin compared to electrocardiography and pulse oximetry
- Research Article
- Synchronization in wireless biomedical-sensor networks with Bluetooth Low Energy
- Research Article
- Automated classification of stages of anaesthesia by populations of evolutionary optimized fuzzy rules
- Research Article
- Effects of sampling rate on automated fatigue recognition in surface EMG signals
- Research Article
- Closed-loop transcranial alternating current stimulation of slow oscillations
- Research Article
- Cardiac index in atrio- and interventricular delay optimized cardiac resynchronization therapy and cardiac contractility modulation
- Research Article
- The role of expert evaluation for microsleep detection
- Research Article
- The impact of baseline wander removal techniques on the ST segment in simulated ischemic 12-lead ECGs
- Research Article
- Metal artifact reduction by projection replacements and non-local prior image integration
- Research Article
- A novel coaxial nozzle for in-process adjustment of electrospun scaffolds’ fiber diameter
- Research Article
- Processing of membranes for oxygenation using the Bellhouse-effect
- Research Article
- Inkjet printing of viable human dental follicle stem cells
- Research Article
- The use of an icebindingprotein out of the snowflea Hypogastrura harveyi as a cryoprotectant in the cryopreservation of mesenchymal stem cells
- Research Article
- New NIR spectroscopy based method to determine ischemia in vivo in liver – a first study on rats
- Research Article
- QRS and QT ventricular conduction times and permanent pacemaker therapy after transcatheter aortic valve implantation
- Research Article
- Adopting oculopressure tonometry as a transient in vivo rabbit glaucoma model
- Research Article
- Next-generation vision testing: the quick CSF
- Research Article
- Improving tactile sensation in laparoscopic surgery by overcoming size restrictions
- Research Article
- Design and control of a 3-DOF hydraulic driven surgical instrument
- Research Article
- Evaluation of endourological tools to improve the diagnosis and therapy of ureteral tumors – from model development to clinical application
- Research Article
- Frequency based assessment of surgical activities
- Research Article
- “Hands free for intervention”, a new approach for transoral endoscopic surgery
- Research Article
- Pseudo-haptic feedback in medical teleoperation
- Research Article
- Feasibility of interactive gesture control of a robotic microscope
- Research Article
- Towards structuring contextual information for workflow-driven surgical assistance functionalities
- Research Article
- Towards a framework for standardized semantic workflow modeling and management in the surgical domain
- Research Article
- Closed-loop approach for situation awareness of medical devices and operating room infrastructure
- Research Article
- Kinect based physiotherapy system for home use
- Research Article
- Evaluating the microsoft kinect skeleton joint tracking as a tool for home-based physiotherapy
- Research Article
- Integrating multimodal information for intraoperative assistance in neurosurgery
- Research Article
- Respiratory motion tracking using Microsoft’s Kinect v2 camera
- Research Article
- Using smart glasses for ultrasound diagnostics
- Research Article
- Measurement of needle susceptibility artifacts in magnetic resonance images
- Research Article
- Dimensionality reduction of medical image descriptors for multimodal image registration
- Research Article
- Experimental evaluation of different weighting schemes in magnetic particle imaging reconstruction
- Research Article
- Evaluation of CT capability for the detection of thin bone structures
- Research Article
- Towards contactless optical coherence elastography with acoustic tissue excitation
- Research Article
- Development and implementation of algorithms for automatic and robust measurement of the 2D:4D digit ratio using image data
- Research Article
- Automated high-throughput analysis of B cell spreading on immobilized antibodies with whole slide imaging
- Research Article
- Tissue segmentation from head MRI: a ground truth validation for feature-enhanced tracking
- Research Article
- Video tracking of swimming rodents on a reflective water surface
- Research Article
- MR imaging of model drug distribution in simulated vitreous
- Research Article
- Studying the extracellular contribution to the double wave vector diffusion-weighted signal
- Research Article
- Artifacts in field free line magnetic particle imaging in the presence of inhomogeneous and nonlinear magnetic fields
- Research Article
- Introducing a frequency-tunable magnetic particle spectrometer
- Research Article
- Imaging of aortic valve dynamics in 4D OCT
- Research Article
- Intravascular optical coherence tomography (OCT) as an additional tool for the assessment of stent structures
- Research Article
- Simple concept for a wide-field lensless digital holographic microscope using a laser diode
- Research Article
- Intraoperative identification of somato-sensory brain areas using optical imaging and standard RGB camera equipment – a feasibility study
- Research Article
- Respiratory surface motion measurement by Microsoft Kinect
- Research Article
- Improving image quality in EIT imaging by measurement of thorax excursion
- Research Article
- A clustering based dual model framework for EIT imaging: first experimental results
- Research Article
- Three-dimensional anisotropic regularization for limited angle tomography
- Research Article
- GPU-based real-time generation of large ultrasound volumes from freehand 3D sweeps
- Research Article
- Experimental computer tomograph
- Research Article
- US-tracked steered FUS in a respiratory ex vivo ovine liver phantom
- Research Article
- Contribution of brownian rotation and particle assembly polarisation to the particle response in magnetic particle spectrometry
- Research Article
- Preliminary investigations of magnetic modulated nanoparticles for microwave breast cancer detection
- Research Article
- Construction of a device for magnetic separation of superparamagnetic iron oxide nanoparticles
- Research Article
- An IHE-conform telecooperation platform supporting the treatment of dementia patients
- Research Article
- Automated respiratory therapy system based on the ARDSNet protocol with systemic perfusion control
- Research Article
- Identification of surgical instruments using UHF-RFID technology
- Research Article
- A generic concept for the development of model-guided clinical decision support systems
- Research Article
- Evaluation of local alterations in femoral bone mineral density measured via quantitative CT
- Research Article
- Creating 3D gelatin phantoms for experimental evaluation in biomedicine
- Research Article
- Influence of short-term fixation with mixed formalin or ethanol solution on the mechanical properties of human cortical bone
- Research Article
- Analysis of the release kinetics of surface-bound proteins via laser-induced fluorescence
- Research Article
- Tomographic particle image velocimetry of a water-jet for low volume harvesting of fat tissue for regenerative medicine
- Research Article
- Wireless medical sensors – context, robustness and safety
- Research Article
- Sequences for real-time magnetic particle imaging
- Research Article
- Speckle-based off-axis holographic detection for non-contact photoacoustic tomography
- Research Article
- A machine learning approach for planning valve-sparing aortic root reconstruction
- Research Article
- An in-ear pulse wave velocity measurement system using heart sounds as time reference
- Research Article
- Measuring different oxygenation levels in a blood perfusion model simulating the human head using NIRS
- Research Article
- Multisegmental fusion of the lumbar spine a curse or a blessing?
- Research Article
- Numerical analysis of the biomechanical complications accompanying the total hip replacement with NANOS-Prosthetic: bone remodelling and prosthesis migration
- Research Article
- A muscle model for hybrid muscle activation
- Research Article
- Mathematical, numerical and in-vitro investigation of cooling performance of an intra-carotid catheter for selective brain hypothermia
- Research Article
- An ideally parameterized unscented Kalman filter for the inverse problem of electrocardiography
- Research Article
- Interactive visualization of cardiac anatomy and atrial excitation for medical diagnosis and research
- Research Article
- Virtualizing clinical cases of atrial flutter in a fast marching simulation including conduction velocity and ablation scars
- Research Article
- Mesh structure-independent modeling of patient-specific atrial fiber orientation
- Research Article
- Accelerating mono-domain cardiac electrophysiology simulations using OpenCL
- Research Article
- Understanding the cellular mode of action of vernakalant using a computational model: answers and new questions
- Research Article
- A java based simulator with user interface to simulate ventilated patients
- Research Article
- Evaluation of an algorithm to choose between competing models of respiratory mechanics
- Research Article
- Numerical simulation of low-pulsation gerotor pumps for use in the pharmaceutical industry and in biomedicine
- Research Article
- Numerical and experimental flow analysis in centifluidic systems for rapid allergy screening tests
- Research Article
- Biomechanical parameter determination of scaffold-free cartilage constructs (SFCCs) with the hyperelastic material models Yeoh, Ogden and Demiray
- Research Article
- FPGA controlled artificial vascular system
- Research Article
- Simulation based investigation of source-detector configurations for non-invasive fetal pulse oximetry
- Research Article
- Test setup for characterizing the efficacy of embolic protection devices
- Research Article
- Impact of electrode geometry on force generation during functional electrical stimulation
- Research Article
- 3D-based visual physical activity assessment of children
- Research Article
- Realtime assessment of foot orientation by Accelerometers and Gyroscopes
- Research Article
- Image based reconstruction for cystoscopy
- Research Article
- Image guided surgery innovation with graduate students - a new lecture format
- Research Article
- Multichannel FES parameterization for controlling foot motion in paretic gait
- Research Article
- Smartphone supported upper limb prosthesis
- Research Article
- Use of quantitative tremor evaluation to enhance target selection during deep brain stimulation surgery for essential tremor
- Research Article
- Evaluation of adhesion promoters for Parylene C on gold metallization
- Research Article
- The influence of metallic ions from CoCr28Mo6 on the osteogenic differentiation and cytokine release of human osteoblasts
- Research Article
- Increasing the visibility of thin NITINOL vascular implants
- Research Article
- Possible reasons for early artificial bone failure in biomechanical tests of ankle arthrodesis systems
- Research Article
- Development of a bending test procedure for the characterization of flexible ECoG electrode arrays
- Research Article
- Tubular manipulators: a new concept for intracochlear positioning of an auditory prosthesis
- Research Article
- Investigation of the dynamic diameter deformation of vascular stents during fatigue testing with radial loading
- Research Article
- Electrospun vascular grafts with anti-kinking properties
- Research Article
- Integration of temperature sensors in polyimide-based thin-film electrode arrays
- Research Article
- Use cases and usability challenges for head-mounted displays in healthcare
- Research Article
- Device- and service profiles for integrated or systems based on open standards
- Research Article
- Risk management for medical devices in research projects
- Research Article
- Simulation of varying femoral attachment sites of medial patellofemoral ligament using a musculoskeletal multi-body model
- Research Article
- Does enhancing consciousness for strategic planning processes support the effectiveness of problem-based learning concepts in biomedical education?
- Research Article
- SPIO processing in macrophages for MPI: The breast cancer MPI-SNLB-concept
- Research Article
- Numerical simulations of airflow in the human pharynx of OSAHS patients
Artikel in diesem Heft
- Research Article
- Development and characterization of superparamagnetic coatings
- Research Article
- The development of an experimental setup to measure acousto-electric interaction signal
- Research Article
- Stability analysis of ferrofluids
- Research Article
- Investigation of endothelial growth using a sensors-integrated microfluidic system to simulate physiological barriers
- Research Article
- Energy harvesting for active implants: powering a ruminal pH-monitoring system
- Research Article
- New type of fluxgate magnetometer for the heart’s magnetic fields detection
- Research Article
- Field mapping of ballistic pressure pulse sources
- Research Article
- Development of a new homecare sleep monitor using body sounds and motion tracking
- Research Article
- Noise properties of textile, capacitive EEG electrodes
- Research Article
- Detecting phase singularities and rotor center trajectories based on the Hilbert transform of intraatrial electrograms in an atrial voxel model
- Research Article
- Spike sorting: the overlapping spikes challenge
- Research Article
- Separating the effect of respiration from the heart rate variability for cases of constant harmonic breathing
- Research Article
- Locating regions of arrhythmogenic substrate by analyzing the duration of triggered atrial activities
- Research Article
- Combining different ECG derived respiration tracking methods to create an optimal reconstruction of the breathing pattern
- Research Article
- Atrial and ventricular signal averaging electrocardiography in pacemaker and cardiac resynchronization therapy
- Research Article
- Estimation of a respiratory signal from a single-lead ECG using the 4th order central moments
- Research Article
- Compressed sensing of multi-lead ECG signals by compressive multiplexing
- Research Article
- Heart rate monitoring in ultra-high-field MRI using frequency information obtained from video signals of the human skin compared to electrocardiography and pulse oximetry
- Research Article
- Synchronization in wireless biomedical-sensor networks with Bluetooth Low Energy
- Research Article
- Automated classification of stages of anaesthesia by populations of evolutionary optimized fuzzy rules
- Research Article
- Effects of sampling rate on automated fatigue recognition in surface EMG signals
- Research Article
- Closed-loop transcranial alternating current stimulation of slow oscillations
- Research Article
- Cardiac index in atrio- and interventricular delay optimized cardiac resynchronization therapy and cardiac contractility modulation
- Research Article
- The role of expert evaluation for microsleep detection
- Research Article
- The impact of baseline wander removal techniques on the ST segment in simulated ischemic 12-lead ECGs
- Research Article
- Metal artifact reduction by projection replacements and non-local prior image integration
- Research Article
- A novel coaxial nozzle for in-process adjustment of electrospun scaffolds’ fiber diameter
- Research Article
- Processing of membranes for oxygenation using the Bellhouse-effect
- Research Article
- Inkjet printing of viable human dental follicle stem cells
- Research Article
- The use of an icebindingprotein out of the snowflea Hypogastrura harveyi as a cryoprotectant in the cryopreservation of mesenchymal stem cells
- Research Article
- New NIR spectroscopy based method to determine ischemia in vivo in liver – a first study on rats
- Research Article
- QRS and QT ventricular conduction times and permanent pacemaker therapy after transcatheter aortic valve implantation
- Research Article
- Adopting oculopressure tonometry as a transient in vivo rabbit glaucoma model
- Research Article
- Next-generation vision testing: the quick CSF
- Research Article
- Improving tactile sensation in laparoscopic surgery by overcoming size restrictions
- Research Article
- Design and control of a 3-DOF hydraulic driven surgical instrument
- Research Article
- Evaluation of endourological tools to improve the diagnosis and therapy of ureteral tumors – from model development to clinical application
- Research Article
- Frequency based assessment of surgical activities
- Research Article
- “Hands free for intervention”, a new approach for transoral endoscopic surgery
- Research Article
- Pseudo-haptic feedback in medical teleoperation
- Research Article
- Feasibility of interactive gesture control of a robotic microscope
- Research Article
- Towards structuring contextual information for workflow-driven surgical assistance functionalities
- Research Article
- Towards a framework for standardized semantic workflow modeling and management in the surgical domain
- Research Article
- Closed-loop approach for situation awareness of medical devices and operating room infrastructure
- Research Article
- Kinect based physiotherapy system for home use
- Research Article
- Evaluating the microsoft kinect skeleton joint tracking as a tool for home-based physiotherapy
- Research Article
- Integrating multimodal information for intraoperative assistance in neurosurgery
- Research Article
- Respiratory motion tracking using Microsoft’s Kinect v2 camera
- Research Article
- Using smart glasses for ultrasound diagnostics
- Research Article
- Measurement of needle susceptibility artifacts in magnetic resonance images
- Research Article
- Dimensionality reduction of medical image descriptors for multimodal image registration
- Research Article
- Experimental evaluation of different weighting schemes in magnetic particle imaging reconstruction
- Research Article
- Evaluation of CT capability for the detection of thin bone structures
- Research Article
- Towards contactless optical coherence elastography with acoustic tissue excitation
- Research Article
- Development and implementation of algorithms for automatic and robust measurement of the 2D:4D digit ratio using image data
- Research Article
- Automated high-throughput analysis of B cell spreading on immobilized antibodies with whole slide imaging
- Research Article
- Tissue segmentation from head MRI: a ground truth validation for feature-enhanced tracking
- Research Article
- Video tracking of swimming rodents on a reflective water surface
- Research Article
- MR imaging of model drug distribution in simulated vitreous
- Research Article
- Studying the extracellular contribution to the double wave vector diffusion-weighted signal
- Research Article
- Artifacts in field free line magnetic particle imaging in the presence of inhomogeneous and nonlinear magnetic fields
- Research Article
- Introducing a frequency-tunable magnetic particle spectrometer
- Research Article
- Imaging of aortic valve dynamics in 4D OCT
- Research Article
- Intravascular optical coherence tomography (OCT) as an additional tool for the assessment of stent structures
- Research Article
- Simple concept for a wide-field lensless digital holographic microscope using a laser diode
- Research Article
- Intraoperative identification of somato-sensory brain areas using optical imaging and standard RGB camera equipment – a feasibility study
- Research Article
- Respiratory surface motion measurement by Microsoft Kinect
- Research Article
- Improving image quality in EIT imaging by measurement of thorax excursion
- Research Article
- A clustering based dual model framework for EIT imaging: first experimental results
- Research Article
- Three-dimensional anisotropic regularization for limited angle tomography
- Research Article
- GPU-based real-time generation of large ultrasound volumes from freehand 3D sweeps
- Research Article
- Experimental computer tomograph
- Research Article
- US-tracked steered FUS in a respiratory ex vivo ovine liver phantom
- Research Article
- Contribution of brownian rotation and particle assembly polarisation to the particle response in magnetic particle spectrometry
- Research Article
- Preliminary investigations of magnetic modulated nanoparticles for microwave breast cancer detection
- Research Article
- Construction of a device for magnetic separation of superparamagnetic iron oxide nanoparticles
- Research Article
- An IHE-conform telecooperation platform supporting the treatment of dementia patients
- Research Article
- Automated respiratory therapy system based on the ARDSNet protocol with systemic perfusion control
- Research Article
- Identification of surgical instruments using UHF-RFID technology
- Research Article
- A generic concept for the development of model-guided clinical decision support systems
- Research Article
- Evaluation of local alterations in femoral bone mineral density measured via quantitative CT
- Research Article
- Creating 3D gelatin phantoms for experimental evaluation in biomedicine
- Research Article
- Influence of short-term fixation with mixed formalin or ethanol solution on the mechanical properties of human cortical bone
- Research Article
- Analysis of the release kinetics of surface-bound proteins via laser-induced fluorescence
- Research Article
- Tomographic particle image velocimetry of a water-jet for low volume harvesting of fat tissue for regenerative medicine
- Research Article
- Wireless medical sensors – context, robustness and safety
- Research Article
- Sequences for real-time magnetic particle imaging
- Research Article
- Speckle-based off-axis holographic detection for non-contact photoacoustic tomography
- Research Article
- A machine learning approach for planning valve-sparing aortic root reconstruction
- Research Article
- An in-ear pulse wave velocity measurement system using heart sounds as time reference
- Research Article
- Measuring different oxygenation levels in a blood perfusion model simulating the human head using NIRS
- Research Article
- Multisegmental fusion of the lumbar spine a curse or a blessing?
- Research Article
- Numerical analysis of the biomechanical complications accompanying the total hip replacement with NANOS-Prosthetic: bone remodelling and prosthesis migration
- Research Article
- A muscle model for hybrid muscle activation
- Research Article
- Mathematical, numerical and in-vitro investigation of cooling performance of an intra-carotid catheter for selective brain hypothermia
- Research Article
- An ideally parameterized unscented Kalman filter for the inverse problem of electrocardiography
- Research Article
- Interactive visualization of cardiac anatomy and atrial excitation for medical diagnosis and research
- Research Article
- Virtualizing clinical cases of atrial flutter in a fast marching simulation including conduction velocity and ablation scars
- Research Article
- Mesh structure-independent modeling of patient-specific atrial fiber orientation
- Research Article
- Accelerating mono-domain cardiac electrophysiology simulations using OpenCL
- Research Article
- Understanding the cellular mode of action of vernakalant using a computational model: answers and new questions
- Research Article
- A java based simulator with user interface to simulate ventilated patients
- Research Article
- Evaluation of an algorithm to choose between competing models of respiratory mechanics
- Research Article
- Numerical simulation of low-pulsation gerotor pumps for use in the pharmaceutical industry and in biomedicine
- Research Article
- Numerical and experimental flow analysis in centifluidic systems for rapid allergy screening tests
- Research Article
- Biomechanical parameter determination of scaffold-free cartilage constructs (SFCCs) with the hyperelastic material models Yeoh, Ogden and Demiray
- Research Article
- FPGA controlled artificial vascular system
- Research Article
- Simulation based investigation of source-detector configurations for non-invasive fetal pulse oximetry
- Research Article
- Test setup for characterizing the efficacy of embolic protection devices
- Research Article
- Impact of electrode geometry on force generation during functional electrical stimulation
- Research Article
- 3D-based visual physical activity assessment of children
- Research Article
- Realtime assessment of foot orientation by Accelerometers and Gyroscopes
- Research Article
- Image based reconstruction for cystoscopy
- Research Article
- Image guided surgery innovation with graduate students - a new lecture format
- Research Article
- Multichannel FES parameterization for controlling foot motion in paretic gait
- Research Article
- Smartphone supported upper limb prosthesis
- Research Article
- Use of quantitative tremor evaluation to enhance target selection during deep brain stimulation surgery for essential tremor
- Research Article
- Evaluation of adhesion promoters for Parylene C on gold metallization
- Research Article
- The influence of metallic ions from CoCr28Mo6 on the osteogenic differentiation and cytokine release of human osteoblasts
- Research Article
- Increasing the visibility of thin NITINOL vascular implants
- Research Article
- Possible reasons for early artificial bone failure in biomechanical tests of ankle arthrodesis systems
- Research Article
- Development of a bending test procedure for the characterization of flexible ECoG electrode arrays
- Research Article
- Tubular manipulators: a new concept for intracochlear positioning of an auditory prosthesis
- Research Article
- Investigation of the dynamic diameter deformation of vascular stents during fatigue testing with radial loading
- Research Article
- Electrospun vascular grafts with anti-kinking properties
- Research Article
- Integration of temperature sensors in polyimide-based thin-film electrode arrays
- Research Article
- Use cases and usability challenges for head-mounted displays in healthcare
- Research Article
- Device- and service profiles for integrated or systems based on open standards
- Research Article
- Risk management for medical devices in research projects
- Research Article
- Simulation of varying femoral attachment sites of medial patellofemoral ligament using a musculoskeletal multi-body model
- Research Article
- Does enhancing consciousness for strategic planning processes support the effectiveness of problem-based learning concepts in biomedical education?
- Research Article
- SPIO processing in macrophages for MPI: The breast cancer MPI-SNLB-concept
- Research Article
- Numerical simulations of airflow in the human pharynx of OSAHS patients