Skip to main content
Article Open Access

From imaging to hemodynamics – how reconstruction kernels influence the blood flow predictions in intracranial aneurysms

  • EMAIL logo , , , , , and
Published/Copyright: September 30, 2016
Download Article (PDF)
Become an author with De Gruyter Brill
Author Information Explore this Subject
Current Directions in Biomedical Engineering
From the journal Current Directions in Biomedical Engineering Volume 2 Issue 1

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.

Keywords: Computational fluid dynamics; Hemodynamics; Intracranial aneurysm; Reconstruction

1 Introduction

Within the last decades, computational fluid dynamics (CFD) has been increasingly used to predict blood flow in intracranial aneurysms (IAs). Studies of large cohorts of patient-specific dilatations mainly try to understand initiation, remodelling as well as rupture processes in order to assist physicians during therapy planning [1], [2]. However, due to several assumptions, which are required to receive numerical results in a feasible time frame, the acceptance of CFD remains limited in the clinical context.

Therefore, several groups mainly focused on the evaluation of the variability of hemodynamic predictions based on varying input parameters. Berg et al. [3] compared in a double-blinded, international CFD challenge numerical solutions of 28 participating groups for two patient-specific IAs under given boundary conditions. The results were in a good agreement with only few outliers due to invalidated solvers or inadvertence during post-processing. To quantify the impact of geometry, Szikora et al. [4] simulated the blood flow in 21 IAs. They concluded that IAs with a main axis parallel to the parent artery are more prone to rupture than those with a perpendicular axis. Geers et al. [5] compared computer tomographic angiography and 3D rotational angiography (RA) images to evaluate the reproducibility of computational hemodynamics in IAs. As a result, different imaging modalities lead to equivalent predictions of the main flow characteristics, but large discrepancies in quantitative measurements are present.

This study extends the usual workflow and incorporates the reconstruction process directly from the digital subtraction angiography (DSA) suite Artis Q (Siemens Healthcare GmbH, Forchheim, Germany). Four patient-specific IA data sets are reconstructed with six available kernels. Next, 24 configurations are segmented and analysed regarding the IAs’ morphology and the impact on blood flow prediction.

2 Material and methods

2.1 Case description

Four IAs in four female patients with mean age of 50 years (range 45–59 years) were investigated in this study. Three cases exhibit acute subarachnoid hemorrhage (SAH), and one aneurysm was incidentally found. Clinical condition was poor in two of the patients with acute SAH (grade IV according to Hunt and Hess), the other two patients had no significant neurologic deficits. One IA was located at the anterior communicating artery, one at the posterior communicating artery, one at the segment of the internal carotid artery, and one at the bifurcation of the middle cerebral artery. Their size varied from approximately 2.5 mm to 8.0 mm. All IAs were treated with endovascular coiling.

2.2 Reconstruction and segmentation

From the RA image data, 6 3D-DSA images were reconstructed per patient by using the kernels EE (edge enhanced) smooth, EE normal, EE sharp, Hounsfield unit (HU) smooth, HU normal and HU sharp. This results in a total number of 24 configurations.

For each patient, a threshold-based segmentation, as proposed in [6], was carried out for the HU normal reconstructed DSA image data. Next, the remaining reconstructions of the same patient were carried out such that they exhibit similar contours in a representative slice covering the aneurysm, see Figure 1. Based on each threshold, the iso-surface is extracted to obtain the triangle surface mesh.

Figure 1 To provide comparable segmentations, a slice with the aneurysm of patient VA (indicated with arrowheads, left) is chosen. A threshold is selected such that similar IA segmentations are achieved (see arrow, right). The resulting segmentation masks are color-coded. The reconstruction kernels influence the extent of the segmentation, especially for peripheral vessels (see *, right).
Figure 1

To provide comparable segmentations, a slice with the aneurysm of patient VA (indicated with arrowheads, left) is chosen. A threshold is selected such that similar IA segmentations are achieved (see arrow, right). The resulting segmentation masks are color-coded. The reconstruction kernels influence the extent of the segmentation, especially for peripheral vessels (see *, right).

2.3 Clinical research prototype

The hemodynamic simulations were carried out with a clinical research prototype. To define the cross-sections where in- and outflow boundary conditions are applied, the vessel surfaces were cropped. A time-dependent velocity profile corresponding to a measured flow curve was defined at the inlet and zero-pressure conditions were set at the outlet cross sections. All required settings of the Lattice-Boltzmann solver were pre-defined and could be adjusted by experienced users. Blood was treated as an incompressible (ρ = 1000 kg/m3), Newtonian (η = 4 mPa.s), laminar fluid and rigid walls were assumed. By default, two cardiac cycles were simulated, whereas only the second one was considered. To guarantee an appropriate mesh resolution, an element size of approximately 0.1–0.15 mm was chosen, yielding a coverage of the minimum ostium diameter by at least 20 voxels. Due to the efficient parallelization of the GPU-based solver, computational times of the unsteady simulations were approximately 30–45 min per case.

2.4 Qualitative and quantitative analyses

For a qualitative analysis of the segmented aneurysm models, a simultaneous view of all six surfaces was implemented in MeVisLab 2.8 (MeVis Medical Solutions AG, Bremen, Germany, www.mevislab.de), a tool for medical image processing and visualization, see Figure 2. A transparent shading technique allows for an interactive and combined exploration of the vessel models.

Figure 2 (A)–(F) Transparent, shaded 3D surface views for the six segmentation results for case EM including bifurcations (*) and peripheral vessels (arrowheads). (G) Combined view of all segmentations.
Figure 2

(A)–(F) Transparent, shaded 3D surface views for the six segmentation results for case EM including bifurcations (*) and peripheral vessels (arrowheads). (G) Combined view of all segmentations.

Furthermore, the effect of different segmentations on the subsequent hemodynamic computations was evaluated using centrelines for the velocity fields. In this regard, spatial and temporal influences are considered and the variability of numerical predictions is quantified.

3 Results

3.1 Segmentation results

A 3D view of the segmented IA models is provided in Figure 2. The qualitative analysis revealed the missing of small vessels for smooth and normal reconstructions. Even for larger vessel parts, including the aneurysm neck, segmentations based on sharp reconstructions yield larger diameters. Although the segmentation threshold was carefully adapted such that similar aneurysm head segmentations were obtained, the aneurysm volume decreases from sharp to normal to smooth reconstructions.

Comparison of HU smooth and EE smooth indicates a slightly better result regarding bifurcations (see the example marked with * in Figure 2E). Furthermore, branching vessels next to the aneurysm are better preserved in the EE-based segmentations (see arrowheads in Figure 2A and B).

For comparison of the aneurysm’s inflow zone, the ostium was approximated as intersecting plane dividing the aneurysm from the parent vessel. The resulting areas are compared in Figure 3. Hence, segmentations based on smooth reconstruction kernels yielded larger ostium areas, whereas segmentations based on sharp reconstruction kernels resulted in smaller ostium areas.

Figure 3 Ostium surface areas for the four patients and six segmentation results.
Figure 3

Ostium surface areas for the four patients and six segmentation results.

3.2 Hemodynamic predictions

The effect of different reconstruction kernels on the hemodynamic predictions is exemplarily illustrated in Figure 4 for case MD. The velocity magnitude along the centreline shows a good agreement in the proximal part of the investigated domain. However, the numerical predictions strongly deviate in the distal part, especially between EE and HU. An equivalent behaviour is observed for the pressure predictions (not presented here).

Figure 4 Velocity prediction along the centreline of case MD for the six different reconstruction kernels at one time step (top). Location-dependent normalized standard deviation (SD) illustrated in grey with the mean value presented by a dashed line (bottom).
Figure 4

Velocity prediction along the centreline of case MD for the six different reconstruction kernels at one time step (top). Location-dependent normalized standard deviation (SD) illustrated in grey with the mean value presented by a dashed line (bottom).

To quantify the effect of time-dependency, Table 1 contains the standard deviations normalized to mean values for the four aneurysms at ten time steps over the cardiac cycle. It can be noticed that with increasing inflow velocity the deviations increase with the highest differences at peak-systole. However, the overall differences of the velocity results remain relatively low compared to the strong geometric deviations presented earlier.

Table 1

Normalized standard deviation for centreline velocity at 10 time steps.

CaseNormalized standard deviation [%] over time
EM4.05.93.93.93.94.25.25.14.54.2
MD6.16.05.85.75.96.46.76.56.26.1
VAa6.55.95.55.34.65.87.38.07.06.7
ZKa6.05.95.85.85.86.16.36.46.26.1

Highest values are bold. aindicates that EE sharp is not considered due to unsuccessful simulations.

4 Discussion

The qualitative comparison of the segmentations based on the six reconstruction kernels yields strong differences regarding branching vessels as well as vessel diameters. Sharp kernels tend to produce noisy surfaces, which are not well-suited for simulation. Smooth kernels yield smoother surfaces but are usually accompanied with smaller vessel cross-sections. Furthermore, segmentations based on EE kernels better comprise surrounding vessels and avoid a decrease in the vessel diameter at bifurcations. When analysing quantitative segmentation results, sharp kernels mostly lead to smaller and smooth kernels to larger ostium areas, respectively. Smooth kernels shrink elongated structures like small vessels, but flatten regions with high curvature, and thus increase the neck area. Sharp kernels yield opposite effects.

Equivalent observations are present with respect to the hemodynamic computations. Although the velocity values were in a good agreement in some vessel sections, other regions in the investigated domains clearly depend on the results of the reconstruction kernel. Hence, the results demonstrate how sensitive hemodynamic parameters depend on geometric variations. This awareness should lead to a careful selection of reconstruction kernels, if CFD computations and therefore patient-specific blood flow predictions are desired. As a result, we strongly recommend including the influence of reconstruction kernels into future CFD challenges like the challenge presented in [3].

Within this study the following limitations need to be mentioned: Firstly, the segmentations are based on a global threshold and a locally adapted segmentation may improve the quality of the 3D surface meshes. Secondly, the hemodynamic simulations assume rigid vessel walls without considering fluid-structure interactions. Thirdly, due to the lack of patient-specific boundary conditions, a representative flow curve was applied.

Acknowledgement

The authors warmly acknowledge Dr. Thomas Redel (Siemens Healthcare GmbH, Forchheim, Germany) for his support regarding the clinical research prototype. Further, we thank Marko Bögel (Friedrich-Alexander-University Erlangen-Nürnberg), who supported the segmentation process with fruitful discussions.

Author’s Statement

Research funding: This work was partly funded by the Federal Ministry of Education and Research in Germany within the Research Campus STIMULATE (grant no. 03FO16102A). 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 complies with all the relevant national regulations, institutional policies and was performed in accordance with the tenets of the Helsinki Declaration, and has been approved by the authors’ institutional review board or equivalent committee.

References

[1] Xiang J, Natarajan SK, Tremmel M, Ma D, Mocco J, Hopkins LN, et al. Hemodynamic-morphologic discriminants for intracranial aneurysm rupture. Stroke. 2011;42:144–52.10.1161/STROKEAHA.110.592923Search in Google Scholar PubMed PubMed Central

[2] Cebral JR, Mut F, Weir J, Putman CM. Association of hemodynamic characteristics and cerebral aneurysm rupture. Am J Neuroradiol. 2011;32:264–70.10.3174/ajnr.A2274Search in Google Scholar PubMed PubMed Central

[3] Berg P, Roloff C, Beuing O, Voss S, Sugiyama S, Aristokleous N, et al. The computational fluid dynamics rupture challenge 2013 – phase II: variability of hemodynamic simulations in two intracranial aneurysms. J Biomech Eng. 2015;137:121008.10.1115/1.4031794Search in Google Scholar PubMed

[4] Szikora I, Paal G, Ugron A, Nasztanovics F, Marosfoi M, Berentei Z, et al. Impact of aneurysmal geometry on intraaneurysmal flow: a computerized flow simulation study. Interventional Neuroradiology. 2008;50:411–21.10.1007/s00234-007-0350-xSearch in Google Scholar PubMed

[5] Geers AJ, Larrabide I, Radaelli G, Bogunovic H, Gratama van Andel HAF, Majoie CB, et al. Reproducibility of image-based computational hemodynamics in intracranial aneurysms: comparison of CTA and 3DRA. Proceeding IEEE International Symposium on Biomedical Imaging: From Nano to Macro; 2009. p. 610–3.10.1109/ISBI.2009.5193121Search in Google Scholar

[6] Glaßer S, Berg P, Neugebauer M, Preim, B. Reconstruction of 3D surface meshes for blood flow simulations of intracranial aneurysms. Proceeding of Computer- und Roboterassistierte Chirurgie (CURA); 2015. p. 163–9.Search in Google Scholar

Published Online: 2016-9-30
Published in Print: 2016-9-1

©2016 Sylvia Glaßer et al., licensee De Gruyter.

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Articles in the same Issue

  1. Synthesis and characterization of PIL/pNIPAAm hybrid hydrogels
  2. Novel blood protein based scaffolds for cardiovascular tissue engineering
  3. Cell adhesion and viability of human endothelial cells on electrospun polymer scaffolds
  4. Effects of heat treatment and welding process on superelastic behaviour and microstructure of micro electron beam welded NiTi
  5. Long-term stable modifications of silicone elastomer for improved hemocompatibility
  6. The effect of thermal treatment on the mechanical properties of PLLA tubular specimens
  7. Biocompatible wear-resistant thick ceramic coating
  8. Protection of active implant electronics with organosilicon open air plasma coating for plastic overmolding
  9. Examination of dielectric strength of thin Parylene C films under various conditions
  10. Open air plasma deposited antimicrobial SiOx/TiOx composite films for biomedical applications
  11. Systemic analysis about residual chloroform in PLLA films
  12. A macrophage model of osseointegration
  13. Towards in silico prognosis using big data
  14. Technical concept and evaluation of a novel shoulder simulator with adaptive muscle force generation and free motion
  15. Usability evaluation of a locomotor therapy device considering different strategies
  16. Hypoxia-on-a-chip
  17. Integration of a semi-automatic in-vitro RFA procedure into an experimental setup
  18. Fabrication of MEMS-based 3D-μECoG-MEAs
  19. High speed digital interfacing for a neural data acquisition system
  20. Bionic forceps for the handling of sensitive tissue
  21. Experimental studies on 3D printing of barium titanate ceramics for medical applications
  22. Patient specific root-analogue dental implants – additive manufacturing and finite element analysis
  23. 3D printing – a key technology for tailored biomedical cell culture lab ware
  24. 3D printing of hydrogels in a temperature controlled environment with high spatial resolution
  25. Biocompatibility of photopolymers for additive manufacturing
  26. Biochemical piezoresistive sensors based on pH- and glucose-sensitive hydrogels for medical applications
  27. Novel wireless measurement system of pressure dedicated to in vivo studies
  28. Portable auricular device for real-time swallow and chew detection
  29. Detection of miRNA using a surface plasmon resonance biosensor and antibody amplification
  30. Simulation and evaluation of stimulation scenarios for targeted vestibular nerve excitation
  31. Deep brain stimulation: increasing efficiency by alternative waveforms
  32. Prediction of immediately occurring microsleep events from brain electric signals
  33. Determining cardiac vagal threshold from short term heart rate complexity
  34. Classification of cardiac excitation patterns during atrial fibrillation
  35. An algorithm to automatically determine the cycle length coverage to identify rotational activity during atrial fibrillation – a simulation study
  36. Deriving respiration from high resolution 12-channel-ECG during cycling exercise
  37. Reducing of gradient induced artifacts on the ECG signal during MRI examinations using Wilcoxon filter
  38. Automatic detection and mapping of double potentials in intracardiac electrograms
  39. Modeling the pelvic region for non-invasive pelvic intraoperative neuromonitoring
  40. Postprocessing algorithm for automated analysis of pelvic intraoperative neuromonitoring signals
  41. Best practice: surgeon driven application in pelvic operations
  42. Vasomotor assessment by camera-based photoplethysmography
  43. Classification of morphologic changes in photoplethysmographic waveforms
  44. Novel computation of pulse transit time from multi-channel PPG signals by wavelet transform
  45. Efficient design of FIR filter based low-pass differentiators for biomedical signal processing
  46. Nonlinear causal influences assessed by mutual compression entropy
  47. Comparative study of methods for solving the correspondence problem in EMD applications
  48. fNIRS for future use in auditory diagnostics
  49. Semi-automated detection of fractional shortening in zebrafish embryo heart videos
  50. Blood pressure measurement on the cheek
  51. Derivation of the respiratory rate from directly and indirectly measured respiratory signals using autocorrelation
  52. Left cardiac atrioventricular delay and inter-ventricular delay in cardiac resynchronization therapy responder and non-responder
  53. An automatic systolic peak detector of blood pressure waveforms using 4th order cumulants
  54. Real-time QRS detection using integrated variance for ECG gated cardiac MRI
  55. Preprocessing of unipolar signals acquired by a novel intracardiac mapping system
  56. In-vitro experiments to characterize ventricular electromechanics
  57. Continuous non-invasive monitoring of blood pressure in the operating room: a cuffless optical technology at the fingertip
  58. Application of microwave sensor technology in cardiovascular disease for plaque detection
  59. Artificial blood circulatory and special Ultrasound Doppler probes for detecting and sizing gaseous embolism
  60. Detection of microsleep events in a car driving simulation study using electrocardiographic features
  61. A method to determine the kink resistance of stents and stent delivery systems according to international standards
  62. Comparison of stented bifurcation and straight vessel 3D-simulation with a prior simulated velocity profile inlet
  63. Transient Euler-Lagrange/DEM simulation of stent thrombosis
  64. Automated control of the laser welding process of heart valve scaffolds
  65. Automation of a test bench for accessing the bendability of electrospun vascular grafts
  66. Influence of storage conditions on the release of growth factors in platelet-rich blood derivatives
  67. Cryopreservation of cells using defined serum-free cryoprotective agents
  68. New bioreactor vessel for tissue engineering of human nasal septal chondrocytes
  69. Determination of the membrane hydraulic permeability of MSCs
  70. Climate retainment in carbon dioxide incubators
  71. Multiple factors influencing OR ventilation system effectiveness
  72. Evaluation of an app-based stress protocol
  73. Medication process in Styrian hospitals
  74. Control tower to surgical theater
  75. Development of a skull phantom for the assessment of implant X-ray visibility
  76. Surgical navigation with QR codes
  77. Investigation of the pressure gradient of embolic protection devices
  78. Computer assistance in femoral derotation osteotomy: a bottom-up approach
  79. Automatic depth scanning system for 3D infrared thermography
  80. A service for monitoring the quality of intraoperative cone beam CT images
  81. Resectoscope with an easy to use twist mechanism for improved handling
  82. In vitro simulation of distribution processes following intramuscular injection
  83. Adjusting inkjet printhead parameters to deposit drugs into micro-sized reservoirs
  84. A flexible standalone system with integrated sensor feedback for multi-pad electrode FES of the hand
  85. Smart control for functional electrical stimulation with optimal pulse intensity
  86. Tactile display on the remaining hand for unilateral hand amputees
  87. Effects of sustained electrical stimulation on spasticity assessed by the pendulum test
  88. An improved tracking framework for ultrasound probe localization in image-guided radiosurgery
  89. Improvement of a subviral particle tracker by the use of a LAP-Kalman-algorithm
  90. Learning discriminative classification models for grading anal intraepithelial neoplasia
  91. Regularization of EIT reconstruction based on multi-scales wavelet transforms
  92. Assessing MRI susceptibility artefact through an indicator of image distortion
  93. EyeGuidance – a computer controlled system to guide eye movements
  94. A framework for feedback-based segmentation of 3D image stacks
  95. Doppler optical coherence tomography as a promising tool for detecting fluid in the human middle ear
  96. 3D Local in vivo Environment (LivE) imaging for single cell protein analysis of bone tissue
  97. Inside-Out access strategy using new trans-vascular catheter approach
  98. US/MRI fusion with new optical tracking and marker approach for interventional procedures inside the MRI suite
  99. Impact of different registration methods in MEG source analysis
  100. 3D segmentation of thyroid ultrasound images using active contours
  101. Designing a compact MRI motion phantom
  102. Cerebral cortex classification by conditional random fields applied to intraoperative thermal imaging
  103. Classification of indirect immunofluorescence images using thresholded local binary count features
  104. Analysis of muscle fatigue conditions using time-frequency images and GLCM features
  105. Numerical evaluation of image parameters of ETR-1
  106. Fabrication of a compliant phantom of the human aortic arch for use in Particle Image Velocimetry (PIV) experimentation
  107. Effect of the number of electrodes on the reconstructed lung shape in electrical impedance tomography
  108. Hardware dependencies of GPU-accelerated beamformer performances for microwave breast cancer detection
  109. Computer assisted assessment of progressing osteoradionecrosis of the jaw for clinical diagnosis and treatment
  110. Evaluation of reconstruction parameters of electrical impedance tomography on aorta detection during saline bolus injection
  111. Evaluation of open-source software for the lung segmentation
  112. Automatic determination of lung features of CF patients in CT scans
  113. Image analysis of self-organized multicellular patterns
  114. Effect of key parameters on synthesis of superparamagnetic nanoparticles (SPIONs)
  115. Radiopacity assessment of neurovascular implants
  116. Development of a desiccant based dielectric for monitoring humidity conditions in miniaturized hermetic implantable packages
  117. Development of an artifact-free aneurysm clip
  118. Enhancing the regeneration of bone defects by alkalizing the peri-implant zone – an in vitro approach
  119. Rapid prototyping of replica knee implants for in vitro testing
  120. Protecting ultra- and hyperhydrophilic implant surfaces in dry state from loss of wettability
  121. Advanced wettability analysis of implant surfaces
  122. Patient-specific hip prostheses designed by surgeons
  123. Plasma treatment on novel carbon fiber reinforced PEEK cages to enhance bioactivity
  124. Wear of a total intervertebral disc prosthesis
  125. Digital health and digital biomarkers – enabling value chains on health data
  126. Usability in the lifecycle of medical software development
  127. Influence of different test gases in a non-destructive 100% quality control system for medical devices
  128. Device development guided by user satisfaction survey on auricular vagus nerve stimulation
  129. Empirical assessment of the time course of innovation in biomedical engineering: first results of a comparative approach
  130. Effect of left atrial hypertrophy on P-wave morphology in a computational model
  131. Simulation of intracardiac electrograms around acute ablation lesions
  132. Parametrization of activation based cardiac electrophysiology models using bidomain model simulations
  133. Assessment of nasal resistance using computational fluid dynamics
  134. Resistance in a non-linear autoregressive model of pulmonary mechanics
  135. Inspiratory and expiratory elastance in a non-linear autoregressive model of pulmonary mechanics
  136. Determination of regional lung function in cystic fibrosis using electrical impedance tomography
  137. Development of parietal bone surrogates for parietal graft lift training
  138. Numerical simulation of mechanically stimulated bone remodelling
  139. Conversion of engineering stresses to Cauchy stresses in tensile and compression tests of thermoplastic polymers
  140. Numerical examinations of simplified spondylodesis models concerning energy absorption in magnetic resonance imaging
  141. Principle study on the signal connection at transabdominal fetal pulse oximetry
  142. Influence of Siluron® insertion on model drug distribution in the simulated vitreous body
  143. Evaluating different approaches to identify a three parameter gas exchange model
  144. Effects of fibrosis on the extracellular potential based on 3D reconstructions from histological sections of heart tissue
  145. From imaging to hemodynamics – how reconstruction kernels influence the blood flow predictions in intracranial aneurysms
  146. Flow optimised design of a novel point-of-care diagnostic device for the detection of disease specific biomarkers
  147. Improved FPGA controlled artificial vascular system for plethysmographic measurements
  148. Minimally spaced electrode positions for multi-functional chest sensors: ECG and respiratory signal estimation
  149. Automated detection of alveolar arches for nasoalveolar molding in cleft lip and palate treatment
  150. Control scheme selection in human-machine- interfaces by analysis of activity signals
  151. Event-based sampling for reducing communication load in realtime human motion analysis by wireless inertial sensor networks
  152. Automatic pairing of inertial sensors to lower limb segments – a plug-and-play approach
  153. Contactless respiratory monitoring system for magnetic resonance imaging applications using a laser range sensor
  154. Interactive monitoring system for visual respiratory biofeedback
  155. Development of a low-cost senor based aid for visually impaired people
  156. Patient assistive system for the shoulder joint
  157. A passive beating heart setup for interventional cardiology training
https://doi.org/10.1515/cdbme-2016-0148
Keywords for this article
Computational fluid dynamics; Hemodynamics; Intracranial aneurysm; Reconstruction
Creative Commons
BY-NC-ND 4.0

Articles in the same Issue

  1. Synthesis and characterization of PIL/pNIPAAm hybrid hydrogels
  2. Novel blood protein based scaffolds for cardiovascular tissue engineering
  3. Cell adhesion and viability of human endothelial cells on electrospun polymer scaffolds
  4. Effects of heat treatment and welding process on superelastic behaviour and microstructure of micro electron beam welded NiTi
  5. Long-term stable modifications of silicone elastomer for improved hemocompatibility
  6. The effect of thermal treatment on the mechanical properties of PLLA tubular specimens
  7. Biocompatible wear-resistant thick ceramic coating
  8. Protection of active implant electronics with organosilicon open air plasma coating for plastic overmolding
  9. Examination of dielectric strength of thin Parylene C films under various conditions
  10. Open air plasma deposited antimicrobial SiOx/TiOx composite films for biomedical applications
  11. Systemic analysis about residual chloroform in PLLA films
  12. A macrophage model of osseointegration
  13. Towards in silico prognosis using big data
  14. Technical concept and evaluation of a novel shoulder simulator with adaptive muscle force generation and free motion
  15. Usability evaluation of a locomotor therapy device considering different strategies
  16. Hypoxia-on-a-chip
  17. Integration of a semi-automatic in-vitro RFA procedure into an experimental setup
  18. Fabrication of MEMS-based 3D-μECoG-MEAs
  19. High speed digital interfacing for a neural data acquisition system
  20. Bionic forceps for the handling of sensitive tissue
  21. Experimental studies on 3D printing of barium titanate ceramics for medical applications
  22. Patient specific root-analogue dental implants – additive manufacturing and finite element analysis
  23. 3D printing – a key technology for tailored biomedical cell culture lab ware
  24. 3D printing of hydrogels in a temperature controlled environment with high spatial resolution
  25. Biocompatibility of photopolymers for additive manufacturing
  26. Biochemical piezoresistive sensors based on pH- and glucose-sensitive hydrogels for medical applications
  27. Novel wireless measurement system of pressure dedicated to in vivo studies
  28. Portable auricular device for real-time swallow and chew detection
  29. Detection of miRNA using a surface plasmon resonance biosensor and antibody amplification
  30. Simulation and evaluation of stimulation scenarios for targeted vestibular nerve excitation
  31. Deep brain stimulation: increasing efficiency by alternative waveforms
  32. Prediction of immediately occurring microsleep events from brain electric signals
  33. Determining cardiac vagal threshold from short term heart rate complexity
  34. Classification of cardiac excitation patterns during atrial fibrillation
  35. An algorithm to automatically determine the cycle length coverage to identify rotational activity during atrial fibrillation – a simulation study
  36. Deriving respiration from high resolution 12-channel-ECG during cycling exercise
  37. Reducing of gradient induced artifacts on the ECG signal during MRI examinations using Wilcoxon filter
  38. Automatic detection and mapping of double potentials in intracardiac electrograms
  39. Modeling the pelvic region for non-invasive pelvic intraoperative neuromonitoring
  40. Postprocessing algorithm for automated analysis of pelvic intraoperative neuromonitoring signals
  41. Best practice: surgeon driven application in pelvic operations
  42. Vasomotor assessment by camera-based photoplethysmography
  43. Classification of morphologic changes in photoplethysmographic waveforms
  44. Novel computation of pulse transit time from multi-channel PPG signals by wavelet transform
  45. Efficient design of FIR filter based low-pass differentiators for biomedical signal processing
  46. Nonlinear causal influences assessed by mutual compression entropy
  47. Comparative study of methods for solving the correspondence problem in EMD applications
  48. fNIRS for future use in auditory diagnostics
  49. Semi-automated detection of fractional shortening in zebrafish embryo heart videos
  50. Blood pressure measurement on the cheek
  51. Derivation of the respiratory rate from directly and indirectly measured respiratory signals using autocorrelation
  52. Left cardiac atrioventricular delay and inter-ventricular delay in cardiac resynchronization therapy responder and non-responder
  53. An automatic systolic peak detector of blood pressure waveforms using 4th order cumulants
  54. Real-time QRS detection using integrated variance for ECG gated cardiac MRI
  55. Preprocessing of unipolar signals acquired by a novel intracardiac mapping system
  56. In-vitro experiments to characterize ventricular electromechanics
  57. Continuous non-invasive monitoring of blood pressure in the operating room: a cuffless optical technology at the fingertip
  58. Application of microwave sensor technology in cardiovascular disease for plaque detection
  59. Artificial blood circulatory and special Ultrasound Doppler probes for detecting and sizing gaseous embolism
  60. Detection of microsleep events in a car driving simulation study using electrocardiographic features
  61. A method to determine the kink resistance of stents and stent delivery systems according to international standards
  62. Comparison of stented bifurcation and straight vessel 3D-simulation with a prior simulated velocity profile inlet
  63. Transient Euler-Lagrange/DEM simulation of stent thrombosis
  64. Automated control of the laser welding process of heart valve scaffolds
  65. Automation of a test bench for accessing the bendability of electrospun vascular grafts
  66. Influence of storage conditions on the release of growth factors in platelet-rich blood derivatives
  67. Cryopreservation of cells using defined serum-free cryoprotective agents
  68. New bioreactor vessel for tissue engineering of human nasal septal chondrocytes
  69. Determination of the membrane hydraulic permeability of MSCs
  70. Climate retainment in carbon dioxide incubators
  71. Multiple factors influencing OR ventilation system effectiveness
  72. Evaluation of an app-based stress protocol
  73. Medication process in Styrian hospitals
  74. Control tower to surgical theater
  75. Development of a skull phantom for the assessment of implant X-ray visibility
  76. Surgical navigation with QR codes
  77. Investigation of the pressure gradient of embolic protection devices
  78. Computer assistance in femoral derotation osteotomy: a bottom-up approach
  79. Automatic depth scanning system for 3D infrared thermography
  80. A service for monitoring the quality of intraoperative cone beam CT images
  81. Resectoscope with an easy to use twist mechanism for improved handling
  82. In vitro simulation of distribution processes following intramuscular injection
  83. Adjusting inkjet printhead parameters to deposit drugs into micro-sized reservoirs
  84. A flexible standalone system with integrated sensor feedback for multi-pad electrode FES of the hand
  85. Smart control for functional electrical stimulation with optimal pulse intensity
  86. Tactile display on the remaining hand for unilateral hand amputees
  87. Effects of sustained electrical stimulation on spasticity assessed by the pendulum test
  88. An improved tracking framework for ultrasound probe localization in image-guided radiosurgery
  89. Improvement of a subviral particle tracker by the use of a LAP-Kalman-algorithm
  90. Learning discriminative classification models for grading anal intraepithelial neoplasia
  91. Regularization of EIT reconstruction based on multi-scales wavelet transforms
  92. Assessing MRI susceptibility artefact through an indicator of image distortion
  93. EyeGuidance – a computer controlled system to guide eye movements
  94. A framework for feedback-based segmentation of 3D image stacks
  95. Doppler optical coherence tomography as a promising tool for detecting fluid in the human middle ear
  96. 3D Local in vivo Environment (LivE) imaging for single cell protein analysis of bone tissue
  97. Inside-Out access strategy using new trans-vascular catheter approach
  98. US/MRI fusion with new optical tracking and marker approach for interventional procedures inside the MRI suite
  99. Impact of different registration methods in MEG source analysis
  100. 3D segmentation of thyroid ultrasound images using active contours
  101. Designing a compact MRI motion phantom
  102. Cerebral cortex classification by conditional random fields applied to intraoperative thermal imaging
  103. Classification of indirect immunofluorescence images using thresholded local binary count features
  104. Analysis of muscle fatigue conditions using time-frequency images and GLCM features
  105. Numerical evaluation of image parameters of ETR-1
  106. Fabrication of a compliant phantom of the human aortic arch for use in Particle Image Velocimetry (PIV) experimentation
  107. Effect of the number of electrodes on the reconstructed lung shape in electrical impedance tomography
  108. Hardware dependencies of GPU-accelerated beamformer performances for microwave breast cancer detection
  109. Computer assisted assessment of progressing osteoradionecrosis of the jaw for clinical diagnosis and treatment
  110. Evaluation of reconstruction parameters of electrical impedance tomography on aorta detection during saline bolus injection
  111. Evaluation of open-source software for the lung segmentation
  112. Automatic determination of lung features of CF patients in CT scans
  113. Image analysis of self-organized multicellular patterns
  114. Effect of key parameters on synthesis of superparamagnetic nanoparticles (SPIONs)
  115. Radiopacity assessment of neurovascular implants
  116. Development of a desiccant based dielectric for monitoring humidity conditions in miniaturized hermetic implantable packages
  117. Development of an artifact-free aneurysm clip
  118. Enhancing the regeneration of bone defects by alkalizing the peri-implant zone – an in vitro approach
  119. Rapid prototyping of replica knee implants for in vitro testing
  120. Protecting ultra- and hyperhydrophilic implant surfaces in dry state from loss of wettability
  121. Advanced wettability analysis of implant surfaces
  122. Patient-specific hip prostheses designed by surgeons
  123. Plasma treatment on novel carbon fiber reinforced PEEK cages to enhance bioactivity
  124. Wear of a total intervertebral disc prosthesis
  125. Digital health and digital biomarkers – enabling value chains on health data
  126. Usability in the lifecycle of medical software development
  127. Influence of different test gases in a non-destructive 100% quality control system for medical devices
  128. Device development guided by user satisfaction survey on auricular vagus nerve stimulation
  129. Empirical assessment of the time course of innovation in biomedical engineering: first results of a comparative approach
  130. Effect of left atrial hypertrophy on P-wave morphology in a computational model
  131. Simulation of intracardiac electrograms around acute ablation lesions
  132. Parametrization of activation based cardiac electrophysiology models using bidomain model simulations
  133. Assessment of nasal resistance using computational fluid dynamics
  134. Resistance in a non-linear autoregressive model of pulmonary mechanics
  135. Inspiratory and expiratory elastance in a non-linear autoregressive model of pulmonary mechanics
  136. Determination of regional lung function in cystic fibrosis using electrical impedance tomography
  137. Development of parietal bone surrogates for parietal graft lift training
  138. Numerical simulation of mechanically stimulated bone remodelling
  139. Conversion of engineering stresses to Cauchy stresses in tensile and compression tests of thermoplastic polymers
  140. Numerical examinations of simplified spondylodesis models concerning energy absorption in magnetic resonance imaging
  141. Principle study on the signal connection at transabdominal fetal pulse oximetry
  142. Influence of Siluron® insertion on model drug distribution in the simulated vitreous body
  143. Evaluating different approaches to identify a three parameter gas exchange model
  144. Effects of fibrosis on the extracellular potential based on 3D reconstructions from histological sections of heart tissue
  145. From imaging to hemodynamics – how reconstruction kernels influence the blood flow predictions in intracranial aneurysms
  146. Flow optimised design of a novel point-of-care diagnostic device for the detection of disease specific biomarkers
  147. Improved FPGA controlled artificial vascular system for plethysmographic measurements
  148. Minimally spaced electrode positions for multi-functional chest sensors: ECG and respiratory signal estimation
  149. Automated detection of alveolar arches for nasoalveolar molding in cleft lip and palate treatment
  150. Control scheme selection in human-machine- interfaces by analysis of activity signals
  151. Event-based sampling for reducing communication load in realtime human motion analysis by wireless inertial sensor networks
  152. Automatic pairing of inertial sensors to lower limb segments – a plug-and-play approach
  153. Contactless respiratory monitoring system for magnetic resonance imaging applications using a laser range sensor
  154. Interactive monitoring system for visual respiratory biofeedback
  155. Development of a low-cost senor based aid for visually impaired people
  156. Patient assistive system for the shoulder joint
  157. A passive beating heart setup for interventional cardiology training
Downloaded on 21.4.2026 from https://www.degruyterbrill.com/document/doi/10.1515/cdbme-2016-0148/html
Scroll to top button