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Yuan, Q., Li, X., Zhou, Z. & Kleiven, S. (2024). A novel framework for video-informed reconstructions of sports accidents: A case study correlating brain injury pattern from multimodal neuroimaging with finite element analysis. Brain Multiphysics, 6, Article ID 100085.
Open this publication in new window or tab >>A novel framework for video-informed reconstructions of sports accidents: A case study correlating brain injury pattern from multimodal neuroimaging with finite element analysis
2024 (English)In: Brain Multiphysics, E-ISSN 2666-5220, Vol. 6, article id 100085Article in journal (Refereed) Published
Abstract [en]

Ski racing is a high-risk sport for traumatic brain injury. A better understanding of the injury mechanism and the development of effective protective equipment remains central to resolving this urgency. Finite element (FE) models are useful tools for studying biomechanical responses of the brain, especially in real-world ski accidents. However, real-world accidents are often captured by handheld monocular cameras; the videos are shaky and lack depth information, making it difficult to estimate reliable impact velocities and posture which are critical for injury prediction. Introducing novel computer vision and deep learning algorithms offers an opportunity to tackle this challenge. This study proposes a novel framework for estimating impact kinematics from handheld, shaky monocular videos of accidents to inform personalized impact simulations. The utility of this framework is demonstrated by reconstructing a ski accident, in which the extracted kinematics are input to a neuroimaging-informed, personalized FE model. The FE-derived responses are compared with imaging-identified brain injury sites of the victim. The results suggest that maximum principal strain may be a useful metric for brain injury. This study demonstrates the potential of video-informed accident reconstructions combined with personalized FE modeling to evaluate individual brain injury. Statement of significance: Reconstructing real-world sports accidents combined with finite element (FE) models presents a unique opportunity to study brain injuries, as it enables simulating complex loading conditions experienced in reality. However, a significant challenge lies in accurately obtaining kinematics from the often shaky, handheld video footage of such accidents. We propose a novel framework that bridges the gap between real-world accidents and video-informed injury predictions. By integrating video analysis, 3D kinematics estimation, and personalized FE simulation, we extract accurate impact kinematics of a ski accident captured from handheld shaky monocular videos to inform personalized impact simulations, predicting the injury pathology identified by multimodal neuroimaging. This study provides important guidance on how best to estimate impact conditions from video-recorded accidents, opening new opportunities to better inform the biomechanical study of head trauma with improved boundary conditions.

Place, publisher, year, edition, pages
Elsevier BV, 2024
Keywords
Computer vision, Kinematics estimation, Personalized finite element model, Sports accidents, Traumatic brain injury
National Category
Other Medical Engineering
Identifiers
urn:nbn:se:kth:diva-341761 (URN)10.1016/j.brain.2023.100085 (DOI)2-s2.0-85179804551 (Scopus ID)
Note

QC 20240102

Available from: 2024-01-02 Created: 2024-01-02 Last updated: 2024-01-02Bibliographically approved
Lindgren, N., Yuan, Q., Pipkorn, B., Kleiven, S. & Li, X. (2024). Development of personalizable female and male pedestrian SAFER human body models. Traffic Injury Prevention, 25(2), 182-193
Open this publication in new window or tab >>Development of personalizable female and male pedestrian SAFER human body models
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2024 (English)In: Traffic Injury Prevention, ISSN 1538-9588, E-ISSN 1538-957X, Vol. 25, no 2, p. 182-193Article in journal (Refereed) Published
Abstract [en]

ObjectivesVulnerable road users are globally overrepresented as victims of road traffic injuries. Developing biofidelic male and female pedestrian human body models (HBMs) that represent diverse anthropometries is essential to enhance road safety and propose intervention strategies.MethodsIn this study, 50th percentile male and female pedestrians of the SAFER HBM were developed via a newly developed image registration-based mesh morphing framework. The performance of the HBMs was evaluated by means of a set of cadaver experiments, involving subjects struck laterally by a generic sedan buck.ResultsIn simulated whole-body pedestrian collisions, the personalized HBMs effectively replicate trajectories of the head and lower body regions, as well as head kinematics, in lateral impacts. The results also demonstrate the personalization framework's capacity to generate personalized HBMs with reliable mesh quality, ensuring robust simulations.ConclusionsThe presented pedestrian HBMs and personalization framework provide robust means to reconstruct and evaluate head impacts in pedestrian-to-vehicle collisions thoroughly and accurately.

Place, publisher, year, edition, pages
Informa UK Limited, 2024
Keywords
Human body model, pedestrian protection, morphing, impact biomechanics
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-342335 (URN)10.1080/15389588.2023.2281280 (DOI)001126484200001 ()38095596 (PubMedID)2-s2.0-85179706101 (Scopus ID)
Note

QC 20240116

Available from: 2024-01-16 Created: 2024-01-16 Last updated: 2024-01-16Bibliographically approved
Huang, Q., Lindgren, N., Kleiven, S. & Li, X. (2023). A method for obtaining case-specific buck models based on vehicle side-view image for pedestrian collision simulations. In: IRCOBI 2023 - Conference Proceedings, International Research Council on the Biomechanics of Injury: . Paper presented at 2023 International Research Council on the Biomechanics of Injury, IRCOBI 2023, Cambridge, United Kingdom of Great Britain and Northern Ireland, Sep 13 2023 - Sep 15 2023 (pp. 499-500). International Research Council on the Biomechanics of Injury
Open this publication in new window or tab >>A method for obtaining case-specific buck models based on vehicle side-view image for pedestrian collision simulations
2023 (English)In: IRCOBI 2023 - Conference Proceedings, International Research Council on the Biomechanics of Injury, International Research Council on the Biomechanics of Injury , 2023, p. 499-500Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
International Research Council on the Biomechanics of Injury, 2023
National Category
Medical Biotechnology
Identifiers
urn:nbn:se:kth:diva-339563 (URN)2-s2.0-85175184149 (Scopus ID)
Conference
2023 International Research Council on the Biomechanics of Injury, IRCOBI 2023, Cambridge, United Kingdom of Great Britain and Northern Ireland, Sep 13 2023 - Sep 15 2023
Note

QC 20231116

Available from: 2023-11-16 Created: 2023-11-16 Last updated: 2023-11-16Bibliographically approved
Zhou, Z., Li, X., Liu, Y., Hardy, W. N. & Kleiven, S. (2023). Brain strain rate response: Addressing computational ambiguity and experimental data for model validation. Brain Multiphysics, 4, Article ID 100073.
Open this publication in new window or tab >>Brain strain rate response: Addressing computational ambiguity and experimental data for model validation
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2023 (English)In: Brain Multiphysics, E-ISSN 2666-5220, Vol. 4, article id 100073Article in journal (Refereed) Published
Abstract [en]

Traumatic brain injury (TBI) is an alarming global public health issue with high morbidity and mortality rates. Although the causal link between external insults and consequent brain injury remains largely elusive, both strain and strain rate are generally recognized as crucial factors for TBI onsets. With respect to the flourishment of strain-based investigation, ambiguity and inconsistency are noted in the scheme for strain rate calculation within the TBI research community. Furthermore, there is no experimental data that can be used to validate the strain rate responses of finite element (FE) models of the human brain. The current work presented a theoretical clarification of two commonly used strain rate computational schemes: the strain rate was either calculated as the time derivative of strain or derived from the rate of deformation tensor. To further substantiate the theoretical disparity, these two schemes were respectively implemented to estimate the strain rate responses from a previous-published cadaveric experiment and an FE head model secondary to a concussive impact. The results clearly showed scheme-dependent responses, both in the experimentally determined principal strain rate and model-derived principal and tract-oriented strain rates. The results highlight that cross-scheme comparison of strain rate responses is inappropriate, and the utilized strain rate computational scheme needs to be reported in future studies. The newly calculated experimental strain rate curves in the supplementary material can be used for strain rate validation of FE head models.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Rate of deformation tensor, Strain rate validation, Time derivative of strain, Traumatic brain injury
National Category
Neurosciences
Identifiers
urn:nbn:se:kth:diva-331558 (URN)10.1016/j.brain.2023.100073 (DOI)2-s2.0-85159719846 (Scopus ID)
Note

QC 20230711

Available from: 2023-07-11 Created: 2023-07-11 Last updated: 2023-07-11Bibliographically approved
Nusia, J., Xu, J. C., Knälmann, J., Sjöblom, R. & Kleiven, S. (2023). Injury risk functions for the four primary knee ligaments. Frontiers in Bioengineering and Biotechnology, 11, Article ID 1228922.
Open this publication in new window or tab >>Injury risk functions for the four primary knee ligaments
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2023 (English)In: Frontiers in Bioengineering and Biotechnology, E-ISSN 2296-4185, Vol. 11, article id 1228922Article in journal (Refereed) Published
Abstract [en]

The purpose of this study was to develop injury risk functions (IRFs) for the anterior and posterior cruciate ligaments (ACL and PCL, respectively) and the medial and lateral collateral ligaments (MCL and LCL, respectively) in the knee joint. The IRFs were based on post-mortem human subjects (PMHSs). Available specimen-specific failure strains were supplemented with statistically generated failure strains (virtual values) to accommodate for unprovided detailed experimental data in the literature. The virtual values were derived from the reported mean and standard deviation in the experimental studies. All virtual and specimen-specific values were thereafter categorized into groups of static and dynamic rates, respectively, and tested for the best fitting theoretical distribution to derive a ligament-specific IRF. A total of 10 IRFs were derived (three for ACL, two for PCL, two for MCL, and three for LCL). ACL, MCL, and LCL received IRFs in both dynamic and static tensile rates, while a sufficient dataset was achieved only for dynamic rates of the PCL. The log-logistic and Weibull distributions had the best fit (p-values: >0.9, RMSE: 2.3%–4.7%) to the empirical datasets for all the ligaments. These IRFs are, to the best of the authors’ knowledge, the first attempt to generate injury prediction tools based on PMHS data for the four knee ligaments. The study has summarized all the relevant literature on PHMS experimental tensile tests on the knee ligaments and utilized the available empirical data to create the IRFs. Future improvements require upcoming experiments to provide comparable testing and strain measurements. Furthermore, emphasis on a clear definition of failure and transparent reporting of each specimen-specific result is necessary.

Place, publisher, year, edition, pages
Frontiers Media SA, 2023
Keywords
collateral ligament, cruciate ligament, cumulative distribution function, failure strain, human body model, injury risk function, knee ligaments
National Category
Orthopaedics
Identifiers
urn:nbn:se:kth:diva-339044 (URN)10.3389/fbioe.2023.1228922 (DOI)001122401900001 ()2-s2.0-85174593217 (Scopus ID)
Note

QC 20231128

Available from: 2023-11-28 Created: 2023-11-28 Last updated: 2024-01-03Bibliographically approved
Makoundou, C., Fathollahi, A., Kleiven, S., Coupe, S. J. & Sangiorgi, C. (2023). Mechanical and leaching characterisation of impact-absorbing rubberised asphalts for urban pavements. Materials and Structures, 56(3), Article ID 55.
Open this publication in new window or tab >>Mechanical and leaching characterisation of impact-absorbing rubberised asphalts for urban pavements
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2023 (English)In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 56, no 3, article id 55Article in journal (Refereed) Published
Abstract [en]

A new impact-absorbing material is being developed to protect vulnerable road users in urban areas and has been produced and tested, mechanically and environmentally in the laboratory. The main constituent of this innovative material is the rubber recycled from end-of-life tyres to foster a circular use of resources and exploit rubber's elastic properties. The study aims to provide a complete Uniaxial Compression Test (UCT) and leaching analysis of the material to propose and optimise a mix that is mechanically sound, durable, and respectful of the environment, in view of in-situ applications. Therefore, the UCT and Dynamic Surface Leaching Test (DSLT) were carried out on rubberised asphalt specimens with different mix designs. The 64 days cumulative concentrations of leached heavy metals and trace elements from unit surface of specimens were calculated and quantified, according to the CEN/TS 16637 standard. In parallel, thanks to a specific mechanical characterisation, compressive stress-strain curves were obtained, and the relaxation and elastic modulus were evaluated. The results from the compression tests showed that the A-mixes have the best elastic and absorbing behaviour, especially those made with an SBS-modified bituminous emulsion (A4). The results from DSLT showed that the cumulative concentration of released elements, per unit surface of specimens were lower than the Dutch Soil Quality Decree (SQD) thresholds, taken as a reference. The low and early release of leachant observed for the mixtures, especially A4 as the most promising one, leave the possibility to handle the leaching with several solutions, including rubber coating treatment or water washing before their incorporation into the mix to limit and prevent their leaching while permitting very high injury reduction performances.

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
Crumb rubber, Rubberised asphalt mixtures, Cold and warm mixtures, Impact-absorbing pavement, Uniaxial compression tests, Dynamic surface leaching
National Category
Materials Engineering Infrastructure Engineering
Identifiers
urn:nbn:se:kth:diva-327396 (URN)10.1617/s11527-022-02078-5 (DOI)000983751300002 ()2-s2.0-85150932407 (Scopus ID)
Note

QC 20230526

Available from: 2023-05-26 Created: 2023-05-26 Last updated: 2023-05-26Bibliographically approved
Li, X., Yuan, Q., Lindgren, N., Huang, Q., Fahlstedt, M., Östh, J., . . . Kleiven, S. (2023). Personalization of human body models and beyond via image registration. Frontiers in Bioengineering and Biotechnology, 11, Article ID 1169365.
Open this publication in new window or tab >>Personalization of human body models and beyond via image registration
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2023 (English)In: Frontiers in Bioengineering and Biotechnology, E-ISSN 2296-4185, Vol. 11, article id 1169365Article in journal (Refereed) Published
Abstract [en]

Finite element human body models (HBMs) are becoming increasingly important numerical tools for traffic safety. Developing a validated and reliable HBM from the start requires integrated efforts and continues to be a challenging task. Mesh morphing is an efficient technique to generate personalized HBMs accounting for individual anatomy once a baseline model has been developed. This study presents a new image registration-based mesh morphing method to generate personalized HBMs. The method is demonstrated by morphing four baseline HBMs (SAFER, THUMS, and VIVA+ in both seated and standing postures) into ten subjects with varying heights, body mass indices (BMIs), and sex. The resulting personalized HBMs show comparable element quality to the baseline models. This method enables the comparison of HBMs by morphing them into the same subject, eliminating geometric differences. The method also shows superior geometry correction capabilities, which facilitates converting a seated HBM to a standing one, combined with additional positioning tools. Furthermore, this method can be extended to personalize other models, and the feasibility of morphing vehicle models has been illustrated. In conclusion, this new image registration-based mesh morphing method allows rapid and robust personalization of HBMs, facilitating personalized simulations.

Place, publisher, year, edition, pages
Frontiers Media SA, 2023
Keywords
finite element human body model, image registration, mesh morphing, personalized simulations, traffic safety
National Category
Vehicle Engineering Medical Ergonomics
Identifiers
urn:nbn:se:kth:diva-329453 (URN)10.3389/fbioe.2023.1169365 (DOI)001000330700001 ()37274163 (PubMedID)2-s2.0-85161047619 (Scopus ID)
Note

QC 20230621

Available from: 2023-06-21 Created: 2023-06-21 Last updated: 2023-06-26Bibliographically approved
Patton, D. A., Mohammadi, R., Halldin, P., Kleiven, S. & McIntosh, A. S. (2023). Radial and Oblique Impact Testing of Alpine Helmets onto Snow Surfaces. Applied Sciences, 13(6), 3455, Article ID 3455.
Open this publication in new window or tab >>Radial and Oblique Impact Testing of Alpine Helmets onto Snow Surfaces
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2023 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 13, no 6, p. 3455-, article id 3455Article in journal (Refereed) Published
Abstract [en]

Recent studies have found that alpine helmets reduce the risk of focal injuries associated with radial impacts, which is likely due to current alpine helmet standards requiring helmets to be drop-tested on flat anvils with only linear acceleration pass criteria. There is a need to evaluate the performance of alpine helmets in more realistic impacts. The current study developed a method to assess the performance of alpine helmets for radial and oblique impacts on snow surfaces in a laboratory setting. Snow samples were collected from a groomed area of a ski slope. Radial impacts were performed as drop tests onto a stationary snow sample. Oblique impacts were performed as drop tests onto a snow sample moving horizontally. For radial impacts, snow sample collection time was found to significantly (p = 0.005) influence mean peak linear headform acceleration with an increase in ambient temperature softening the snow samples. For oblique tests, the recreational alpine sports helmet with a rotation-damping system (RDS) significantly (p = 0.002) reduced mean peak angular acceleration compared to the same helmets with no RDS by approximately 44%. The ski racing helmet also significantly (p = 0.006) reduced mean peak angular acceleration compared to the recreational alpine sports helmet with no RDS by approximately 33%, which was attributed to the smooth outer shell of the ski racing helmet. The current study helps to bridge the knowledge gap between real helmet impacts on alpine snow slopes and laboratory helmet impacts on rigid surfaces.

Place, publisher, year, edition, pages
MDPI AG, 2023
Keywords
alpine sports, head injury, helmets, impact biomechanics, injury prevention, protective equipment, skiing, snowboarding
National Category
Other Medical Engineering
Identifiers
urn:nbn:se:kth:diva-325760 (URN)10.3390/app13063455 (DOI)000957763400001 ()2-s2.0-85152009390 (Scopus ID)
Note

QC 20230414

Available from: 2023-04-14 Created: 2023-04-14 Last updated: 2023-06-08Bibliographically approved
Yuan, Q., Kleiven, S. & Li, X. (2023). Video-based Accurate Human Kinematics Estimation during High-Speed Impact. In: IRCOBI 2023 - Conference Proceedings, International Research Council on the Biomechanics of Injury: . Paper presented at 2023 International Research Council on the Biomechanics of Injury, IRCOBI 2023, Cambridge, United Kingdom of Great Britain and Northern Ireland, Sep 13 2023 - Sep 15 2023 (pp. 631-632). International Research Council on the Biomechanics of Injury
Open this publication in new window or tab >>Video-based Accurate Human Kinematics Estimation during High-Speed Impact
2023 (English)In: IRCOBI 2023 - Conference Proceedings, International Research Council on the Biomechanics of Injury, International Research Council on the Biomechanics of Injury , 2023, p. 631-632Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
International Research Council on the Biomechanics of Injury, 2023
National Category
Medical Biotechnology
Identifiers
urn:nbn:se:kth:diva-339568 (URN)2-s2.0-85175155193 (Scopus ID)
Conference
2023 International Research Council on the Biomechanics of Injury, IRCOBI 2023, Cambridge, United Kingdom of Great Britain and Northern Ireland, Sep 13 2023 - Sep 15 2023
Note

QC 20231116

Available from: 2023-11-16 Created: 2023-11-16 Last updated: 2023-11-16Bibliographically approved
Majdolhosseini, M., Zhou, Z., Kleiven, S. & Villa, A. (2023). Which part of axonal membrane is the most vulnerable: A molecular dynamics/Finite Element study. European Biophysics Journal, 52(SUPPL 1), S39-S39
Open this publication in new window or tab >>Which part of axonal membrane is the most vulnerable: A molecular dynamics/Finite Element study
2023 (English)In: European Biophysics Journal, ISSN 0175-7571, E-ISSN 1432-1017, Vol. 52, no SUPPL 1, p. S39-S39Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
SPRINGER, 2023
National Category
Neurology
Identifiers
urn:nbn:se:kth:diva-335858 (URN)001029235400068 ()
Note

QC 20230911

Available from: 2023-09-11 Created: 2023-09-11 Last updated: 2023-09-11Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-0125-0784

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