Double degree PhD in Mathematical and computer modeling at Charles University in Prague, Czechia, and the University of Groningen, The Netherlands
RESEARCH, TEACHING, or OTHER INTERESTS
Modeling and Simulation, Computational Mathematics
3
Scopus Publications
6
Scholar Citations
2
Scholar h-index
Scopus Publications
On the Numerical Evaluation of Wall Shear Stress Using the Finite Element Method Jana Brunátová, Jørgen S. Dokken, Kristian Valen‐Sendstad, Jaroslav Hron International Journal for Numerical Methods in Biomedical Engineering, 2025 Wall shear stress (WSS) is a crucial hemodynamic quantity extensively studied in cardiovascular research, yet its numerical computation is not straightforward. This work compares WSS results obtained from two different finite element discretizations, quantifies the differences between continuous and discontinuous stresses, and introduces a modified variationally consistent method for WSS evaluation through the formulation of a boundary‐flux problem. Two benchmark problems are considered: a 2D Stokes flow on a unit square and a 3D Poiseuille flow through a cylindrical pipe. These are followed by investigations of steady‐state Navier–Stokes flow in two image‐based, patient‐specific aneurysms. The study focuses on P1/P1 stabilized and Taylor–Hood P2/P1 mixed finite elements for velocity and pressure. WSS is computed using either the proposed boundary‐flux method or as a projection of tangential traction onto first order Lagrange (P1), discontinuous Galerkin first order (DG‐1), or discontinuous Galerkin zero order (DG‐0) space. For the P1/P1 stabilized element, the boundary‐flux and P1 projection methods yielded equivalent results. With the P2/P1 element, the boundary‐flux evaluation demonstrated faster convergence in the Poiseuille flow example but showed increased sensitivity to pressure field inaccuracies in image‐based geometries compared to the projection method. Furthermore, a paradoxical degradation in WSS accuracy was observed when combining the P2/P1 element with fine boundary‐layer meshes on a cylindrical geometry, an effect attributed to inherent geometric approximation errors. In aneurysm geometries, the P2/P1 element exhibited superior robustness to mesh size when evaluating average WSS and low shear area (LSA), outperforming the P1/P1 stabilized element. Projecting discontinuous finite element functions into continuous spaces can introduce artifacts, such as the Gibbs phenomenon. Consequently, it is crucial to carefully select the finite element space for boundary stress calculations, not only in applications involving WSS computations for aneurysms.
Denoising of dual-VENC PC-MRI with large high/low VENC ratios Jana Brunátová, Miriam Löcke, Sergio Uribe, Cristóbal Bertoglio Magnetic Resonance in Medicine, 2025 PurposeDual velocity encoding PC‐MRI can produce spurious artifacts when using high ratios of velocity encoding values (VENCs), limiting its ability to generate high‐quality images across a wide range of encoding velocities. This study aims to propose and compare dual‐VENC correction methods for such artifacts.Theory and MethodsTwo denoising approaches based on spatiotemporal regularization are proposed and compared with a state‐of‐the‐art method based on sign correction. Accuracy is assessed using simulated data from an aorta and brain aneurysm, as well as 8 two‐dimensional (2D) PC‐MRI ascending aorta datasets. Two temporal resolutions (30,60) ms and noise levels (9,12) dB are considered, with noise added to the complex magnetization. The error is evaluated with respect to the noise‐free measurement in the synthetic case and to the unwrapped image without additional noise in the volunteer datasets.ResultsIn all studied cases, the proposed methods are more accurate than the Sign Correction technique. Using simulated 2D+T data from the aorta (60 ms, 9 dB), the Dual‐VENC (DV) error is reduced to: (Sign Correction); and (proposed techniques). The methods are found to be significantly different (p‐value ). Importantly, brain aneurysm data revealed that the Sign Correction method is not suitable, as it increases error when the flow is not unidirectional. All three methods improve the accuracy of in vivo data.ConclusionThe newly proposed methods outperform the Sign Correction method in improving dual‐VENC PC‐MRI images. Among them, the approach based on temporal differences has shown the highest accuracy.
Rupture point is associated with divergent hemodynamics in intracranial aneurysms Aleš Hejčl, Jana Brunátová, Helena Švihlová, Jan Víteček, Andrea Vítečková Wünschová, et al. Frontiers in Neurology, 2024 BackgroundUnderstanding the risk factors leading to intracranial aneurysm (IA) rupture have still not been fully clarified. They are vital for proper medical guidance of patients harboring unruptured IAs. Clarifying the hemodynamics associated with the point of rupture could help could provide useful information about some of the risk factors. Thus far, few studies have studied this issue with often diverging conclusions.MethodsWe identified a point of rupture in patients operated for an IAs during surgery, using a combination of preoperative computed tomography (CT) and computed tomography angiography (CTA). Hemodynamic parameters were calculated both for the aneurysm sac as a whole and the point of rupture. In two cases, the results of CFD were compared with those of the experiment using particle image velocimetry (PIV).ResultsWe were able to identify 6 aneurysms with a well-demarcated point of rupture. In four aneurysms, the rupture point was near the vortex with low wall shear stress (WSS) and high oscillatory shear index (OSI). In one case, the rupture point was in the flow jet with high WSS. In the last case, the rupture point was in the significant bleb and no specific hemodynamic parameters were found. The CFD results were verified in the PIV part of the study.ConclusionOur study shows that different hemodynamic scenarios are associated with the site of IA rupture. The numerical simulations were confirmed by laboratory models. This study further supports the hypothesis that various pathological pathways may lead to aneurysm wall damage resulting in its rupture.
RECENT SCHOLAR PUBLICATIONS
Computational modeling and imaging of hemodynamics in intracranial aneurysms J Brunatova 2026.0
On the numerical evaluation of wall shear stress using the finite element method J Brunátová, JS Dokken, K Valen‐Sendstad, J Hron International Journal for Numerical Methods in Biomedical Engineering 41 (9 … , 2025 2025.0 Citations: 1
Denoising of dual‐VENC PC‐MRI with large high/low VENC ratios J Brunátová, M Löcke, S Uribe, C Bertoglio Magnetic Resonance in Medicine 93 (1), 353-368 , 2025 2025.0 Citations: 2
DIVERGENT HEMODYNAMICS AND MACROPHAGE POLARIZATION TOWARDS M2 SUBTYPE ARE ASSOCIATED WITH INTRACRANIAL ANEURYSM RUPTURE A Hejcl, J Brunatova, J Vitecek, AV Wunschova, T Radovnicky, ... INTERNATIONAL JOURNAL OF STROKE 19 (2), 111-112 , 2024 2024.0
Rupture point is associated with divergent hemodynamics in intracranial aneurysms A Hejčl, J Brunátová, H Švihlová, J Víteček, AV Wünschová, A Sejkorová, ... Frontiers in Neurology 15, 1364105 , 2024 2024.0 Citations: 3
3D-printed models of aneurysms based on patients’ data to study hemodynamic M Torkashvand, L Nováková, A Hejčl, J Brunátová, J Hron, J Víteček, ... 2024.0
Open Library of Bioscience J Brunátová, M Löcke, S Uribe, C Bertoglio
MOST CITED SCHOLAR PUBLICATIONS
Rupture point is associated with divergent hemodynamics in intracranial aneurysms A Hejčl, J Brunátová, H Švihlová, J Víteček, AV Wünschová, A Sejkorová, ... Frontiers in Neurology 15, 1364105 , 2024 2024.0 Citations: 3
Denoising of dual‐VENC PC‐MRI with large high/low VENC ratios J Brunátová, M Löcke, S Uribe, C Bertoglio Magnetic Resonance in Medicine 93 (1), 353-368 , 2025 2025.0 Citations: 2
On the numerical evaluation of wall shear stress using the finite element method J Brunátová, JS Dokken, K Valen‐Sendstad, J Hron International Journal for Numerical Methods in Biomedical Engineering 41 (9 … , 2025 2025.0 Citations: 1
Computational modeling and imaging of hemodynamics in intracranial aneurysms J Brunatova 2026.0
DIVERGENT HEMODYNAMICS AND MACROPHAGE POLARIZATION TOWARDS M2 SUBTYPE ARE ASSOCIATED WITH INTRACRANIAL ANEURYSM RUPTURE A Hejcl, J Brunatova, J Vitecek, AV Wunschova, T Radovnicky, ... INTERNATIONAL JOURNAL OF STROKE 19 (2), 111-112 , 2024 2024.0
3D-printed models of aneurysms based on patients’ data to study hemodynamic M Torkashvand, L Nováková, A Hejčl, J Brunátová, J Hron, J Víteček, ... 2024.0
Open Library of Bioscience J Brunátová, M Löcke, S Uribe, C Bertoglio
