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  1. Article: [Simulation for Endovascular Treatment].

    Kato, Naoki / Fujimura, Soichiro / Sano, Tohru / Enomoto, Hiroyuki / Fuga, Michiyasu / Nagayama, Gota / Hataoka, Shunsuke / Kan, Issei / Ishibashi, Toshihiro / Murayama, Yuichi

    No shinkei geka. Neurological surgery

    2024  Volume 52, Issue 2, Page(s) 263–269

    Abstract: With the advent of high-resolution imaging and advancements in computational fluid dynamics(CFD)and computational structural mechanics(CSM)analyses, clinical simulation of endovascular intervention has gradually become feasible. Virtual stents have ... ...

    Abstract With the advent of high-resolution imaging and advancements in computational fluid dynamics(CFD)and computational structural mechanics(CSM)analyses, clinical simulation of endovascular intervention has gradually become feasible. Virtual stents have become indispensable for coil embolization. For braided stents, such as those with low-profile visualized intraluminal support and flow diverters, predicting postplacement elongation and contraction is challenging; however, software development has enabled more precise treatment planning. Additionally, simulations utilizing three-dimensional(3D)printer models can enable realistic simulations of procedures such as intracranial stents and Woven EndoBridge placement. This approach is beneficial for shunt disorders such as arteriovenous malformations and dural arteriovenous fistulas, offering 3D visualization of shunt access routes and intuitive treatment strategy planning, even for beginners. Furthermore, it can be applied to procedures such as open surgical clipping and nidus resection, aiding in the selection of suitable clips and considerations for ideal resection based on nidus curvature. Simulations using CFD, CSM, and 3D printers are crucial for training surgeons and handling new devices. Harnessing medicine-engineering synergy is essential, and regulatory approval(insurance coverage)and appropriate commercialization of simulations are paramount for the future.
    MeSH term(s) Humans ; Intracranial Aneurysm/surgery ; Endovascular Procedures ; Blood Vessel Prosthesis ; Stents ; Software ; Embolization, Therapeutic/methods ; Treatment Outcome
    Language Japanese
    Publishing date 2024-03-21
    Publishing country Japan
    Document type English Abstract ; Journal Article
    ZDB-ID 197053-7
    ISSN 1882-1251 ; 0301-2603
    ISSN (online) 1882-1251
    ISSN 0301-2603
    DOI 10.11477/mf.1436204910
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Performance of stacked microbial fuel cells with Barley–Shochu waste

    Fujimura, Soichiro / Kamitori, Kazuya / Kamei, Ichiro / Nagamine, Miyuki / Miyoshi, Keiji / Inoue, Kengo

    The Society for Biotechnology, Japan Journal of bioscience and bioengineering. 2022 Feb. 04,

    2022  

    Abstract: The treatment of barley–shochu waste combined with electricity generation was examined using stacked microbial fuel cells (SMFCs). The maximum chemical oxygen demand (CODCᵣ) removal efficiency and maximum power density were achieved at 36.7 ± 1.1% and 4 ... ...

    Abstract The treatment of barley–shochu waste combined with electricity generation was examined using stacked microbial fuel cells (SMFCs). The maximum chemical oxygen demand (CODCᵣ) removal efficiency and maximum power density were achieved at 36.7 ± 1.1% and 4.3 ± 0.2 W m⁻³ (15.7 ± 0.9 mW m⁻²). The acetic acid concentration in effluent increased, whereas the citric acid, ethanol and sugar concentrations decreased during the operation. Microbial community analysis of the anode cell suspension and raw barley–shochu waste revealed that Clostridiaceae, Acetobacteraceae, and Enterobacteriaceae became predominant after the operation, implying that microorganisms belonging to these families might be involved in organic waste decomposition and electricity generation in the SMFCs.
    Keywords Acetobacteraceae ; Clostridiaceae ; Enterobacteriaceae ; acetic acid ; anodes ; chemical oxygen demand ; citric acid ; electricity generation ; ethanol ; microbial communities ; organic wastes ; sugars
    Language English
    Dates of publication 2022-0204
    Publishing place Elsevier B.V.
    Document type Article
    Note Pre-press version
    ZDB-ID 1465387-4
    ISSN 1347-4421 ; 1389-1723
    ISSN (online) 1347-4421
    ISSN 1389-1723
    DOI 10.1016/j.jbiosc.2022.02.004
    Database NAL-Catalogue (AGRICOLA)

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  3. Article ; Online: Performance of stacked microbial fuel cells with barley-shochu waste.

    Fujimura, Soichiro / Kamitori, Kazuya / Kamei, Ichiro / Nagamine, Miyuki / Miyoshi, Keiji / Inoue, Kengo

    Journal of bioscience and bioengineering

    2022  Volume 133, Issue 5, Page(s) 467–473

    Abstract: The treatment of barley-shochu waste combined with electricity generation was examined using stacked microbial fuel cells (SMFCs). The maximum chemical oxygen demand ( ... ...

    Abstract The treatment of barley-shochu waste combined with electricity generation was examined using stacked microbial fuel cells (SMFCs). The maximum chemical oxygen demand (COD
    MeSH term(s) Bioelectric Energy Sources ; Biological Oxygen Demand Analysis ; Electricity ; Electrodes ; Hordeum ; Humans ; Waste Disposal, Fluid ; Waste Water
    Chemical Substances Waste Water
    Language English
    Publishing date 2022-03-03
    Publishing country Japan
    Document type Journal Article
    ZDB-ID 1465387-4
    ISSN 1347-4421 ; 1389-1723
    ISSN (online) 1347-4421
    ISSN 1389-1723
    DOI 10.1016/j.jbiosc.2022.02.004
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Hemodynamic and morphological differences in cerebral aneurysms between before and after rupture.

    Fujimura, Soichiro / Yamanaka, Yuma / Takao, Hiroyuki / Ishibashi, Toshihiro / Otani, Katharina / Karagiozov, Kostadin / Fukudome, Koji / Yamamoto, Makoto / Murayama, Yuichi

    Journal of neurosurgery

    2023  Volume 140, Issue 3, Page(s) 774–782

    Abstract: Objective: Although it has been proposed that aneurysm morphology is different after rupture, detailed research of the morphological changes using 3D imaging acquired before and after rupture has not been conducted because of the difficulty of data ... ...

    Abstract Objective: Although it has been proposed that aneurysm morphology is different after rupture, detailed research of the morphological changes using 3D imaging acquired before and after rupture has not been conducted because of the difficulty of data collection. Similarly, hemodynamic changes due to morphological alterations after rupture have not been analyzed. The aim of this study was to investigate the changes in morphology and hemodynamics observed after aneurysm rupture.
    Methods: For 21 cerebral aneurysms (21 patients) that ruptured during observation, 3D geometry of the aneurysms and parent arteries were reconstructed based on the angiographic images before and after their rupture. In addition, using the reconstructed geometry, blood flow was simulated by computational fluid dynamics (CFD) analysis. Morphological and hemodynamic parameters were calculated both before and after rupture, and their changes from before to after were compared.
    Results: In the morphological parameters, statistically significantly higher values were observed after rupture in height (before: 5.5 ± 2.1 mm, after: 6.1 ± 2.0 mm; p < 0.0001), aspect ratio (p = 0.002), aneurysm volume (p = 0.04), and undulation index (p = 0.005). In terms of hemodynamic changes, the mean normalized wall shear stress (NWSS) decreased significantly (before: 5.4 × 10-1 ± 2.9 × 10-1, after: 4.4 × 10-1 ± 2.8 × 10-1; p < 0.001) as well as the other NWSS parameters, including maximum and minimum NWSS, which were associated with stagnant flow due to the morphological changes after rupture.
    Conclusions: Aneurysm morphology was found to change after rupture into an elongated and irregular geometry, accompanied by an increase in aneurysm volume. These morphological changes were also associated with statistically significant hemodynamic alterations that produced low wall sheer stress by stagnant flow. The authors' results also provide the opportunity to explore and develop a risk evaluation method for aneurysm rupture based on prerupture morphology and hemodynamics by further exploration in this direction.
    MeSH term(s) Humans ; Intracranial Aneurysm/diagnostic imaging ; Hemodynamics ; Aneurysm, Ruptured/diagnostic imaging ; Angiography ; Arteries
    Language English
    Publishing date 2023-09-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3089-2
    ISSN 1933-0693 ; 0022-3085
    ISSN (online) 1933-0693
    ISSN 0022-3085
    DOI 10.3171/2023.6.JNS23289
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Real Stiffness and Vividness Reproduction of Anatomic Structures Into the 3-Dimensional Printed Models Contributes to Improved Simulation and Training in Skull Base Surgery.

    Watanabe, Nobuyuki / Watanabe, Kentaro / Fujimura, Soichiro / Karagiozov, Kostadin L / Mori, Ryosuke / Ishii, Takuya / Murayama, Yuichi / Akasaki, Yasuharu

    Operative neurosurgery (Hagerstown, Md.)

    2023  Volume 24, Issue 5, Page(s) 548–555

    Abstract: Background: Despite the advancement of 3-dimensional (3D) printing technology with medical application, its neurosurgical utility value has been limited to understanding the anatomy of bones, lesions, and their surroundings in the neurosurgical field.!## ...

    Abstract Background: Despite the advancement of 3-dimensional (3D) printing technology with medical application, its neurosurgical utility value has been limited to understanding the anatomy of bones, lesions, and their surroundings in the neurosurgical field.
    Objective: To develop a 3D printed model simulating the surgical technique applied in skull base surgery (SBS), especially to reproduce visually the surgical field together with the mechanical properties of tissues as perceived by the surgeon through procedures performance on a model.
    Methods: The Young modulus representing the degree of stiffness was measured for the tissues of anesthetized animals and printing materials. The stiffness and vividness of models were adjusted appropriately for each structure. Empty spaces were produced inside the models of brains, venous sinuses, and tumors. The 3D printed models were created in 7 cases of SBS planned patients and were used for surgical simulation.
    Results: The Young modulus of pig's brain ranged from 5.56 to 11.01 kPa and goat's brain from 4.51 to 13.69 kPa, and the dura of pig and goat values were 14.00 and 24.62 kPa, respectively. Although the softest printing material had about 20 times of Young modulus compared with animal brain, the hollow structure of brain model gave a soft sensation resembling the real organ and was helpful for bridging the gap between Young moduli values. A dura/tentorium-containing model was practical to simulate the real maneuverability at surgery.
    Conclusion: The stiffness/vividness modulated 3D printed model provides an advanced realistic environment for training and simulation of a wide range of SBS procedures.
    MeSH term(s) Animals ; Swine ; Neurosurgical Procedures/methods ; Computer Simulation ; Brain/surgery ; Printing, Three-Dimensional ; Skull Base/surgery ; Skull Base/anatomy & histology
    Language English
    Publishing date 2023-02-13
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2767575-0
    ISSN 2332-4260 ; 2332-4252
    ISSN (online) 2332-4260
    ISSN 2332-4252
    DOI 10.1227/ons.0000000000000583
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Computational fluid dynamics as a risk assessment tool for aneurysm rupture.

    Murayama, Yuichi / Fujimura, Soichiro / Suzuki, Tomoaki / Takao, Hiroyuki

    Neurosurgical focus

    2019  Volume 47, Issue 1, Page(s) E12

    Abstract: Objective: The authors reviewed the clinical role of computational fluid dynamics (CFD) in assessing the risk of intracranial aneurysm rupture.: Methods: A literature review was performed to identify reports on CFD assessment of aneurysms using ... ...

    Abstract Objective: The authors reviewed the clinical role of computational fluid dynamics (CFD) in assessing the risk of intracranial aneurysm rupture.
    Methods: A literature review was performed to identify reports on CFD assessment of aneurysms using PubMed. The usefulness of various hemodynamic parameters, such as wall shear stress (WSS) and the Oscillatory Shear Index (OSI), and their role in aneurysm rupture risk analysis, were analyzed.
    Results: The authors identified a total of 258 published articles evaluating rupture risk, growth, and endovascular device assessment. Of these 258 articles, 113 matching for CFD and hemodynamic parameters that contribute to the risk of rupture (such as WSS and OSI) were identified. However, due to a lack of standardized methodology, controversy remains on each parameter's role.
    Conclusions: Although controversy continues to exist on which risk factors contribute to predict aneurysm rupture, CFD can provide additional parameters to assess this rupture risk. This technology can contribute to clinical decision-making or evaluation of efficacy for endovascular methods and devices.
    MeSH term(s) Aneurysm, Ruptured/diagnosis ; Aneurysm, Ruptured/physiopathology ; Animals ; Hemodynamics ; Humans ; Hydrodynamics ; Intracranial Aneurysm/diagnosis ; Intracranial Aneurysm/physiopathology ; Risk Assessment ; Stress, Physiological
    Language English
    Publishing date 2019-06-29
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 2026589-X
    ISSN 1092-0684 ; 1092-0684
    ISSN (online) 1092-0684
    ISSN 1092-0684
    DOI 10.3171/2019.4.FOCUS19189
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Computational modeling of braided-stent deployment for interpreting the mechanism of stent flattening.

    Shiozaki, Shunya / Otani, Tomohiro / Fujimura, Soichiro / Takao, Hiroyuki / Wada, Shigeo

    International journal for numerical methods in biomedical engineering

    2020  Volume 37, Issue 12, Page(s) e3335

    Abstract: This study develops a computational model of the braided stent for interpreting the mechanism of stent flattening during deployment into curved arteries. Stent wires are expressed using Kirchhoff's rod theory and their mechanical behavior is treated ... ...

    Abstract This study develops a computational model of the braided stent for interpreting the mechanism of stent flattening during deployment into curved arteries. Stent wires are expressed using Kirchhoff's rod theory and their mechanical behavior is treated using a corotational beam formulation. The equation of motion of the braided stent is solved in a step-by-step manner using the resultant elastic force and mechanical interactions of wires with friction. Examples of braided-stent deployment into idealized arteries with various curvatures are numerically simulated. In cases of low curvature, the braided stent expands from a catheter by releasing the bending energy stored in stent wires, while incomplete expansion is found at both stent ends (ie, the fish-mouth phenomenon), where relatively little bending energy is stored. In cases of high curvature, much torsional energy is stored in stent wires locally in the midsection of the curvature and the bending energy for stent self-expansion is not fully released even after deployment, leading to stent flattening. These findings suggest that the mechanical state of the braided stent and its transition during deployment play an important role in the underlying mechanism of stent flattening. NOVELTY STATEMENT: This study developed a computational mechanical model of the braided stent for interpreting stent flattening, which is a critical issue observed during deployment into highly curved arteries. Mechanical behaviors of the stent wires are appropriately treated by corotational beam element formulation with considering multiple contacts. We conducted numerical examples of the stent deployment into curved arteries and found that the mechanical state of the braided stent during deployment associated with occurrences of the stent flattening. We believe this finding gives new insight into the mechanism of stent flattening and would advance the design of the stent and its deployment protocol.
    MeSH term(s) Arteries ; Computer Simulation ; Mechanical Phenomena ; Prosthesis Design ; Stents
    Language English
    Publishing date 2020-04-07
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2540968-2
    ISSN 2040-7947 ; 2040-7939
    ISSN (online) 2040-7947
    ISSN 2040-7939
    DOI 10.1002/cnm.3335
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Development of Machine Learning Model for Selecting the 1st Coil in the Treatment of Cerebral Aneurysms by Coil Embolization.

    Fujimura, Soichiro / Koshiba, Toshiki / Kudo, Genki / Takeshita, Kohei / Kazama, Masahiro / Karagiozov, Kostadin / Fukudome, Koji / Takao, Hiroyuki / Ohwada, Hayato / Murayama, Yuichi / Yamamoto, Makoto / Ishibashi, Toshihiro / Otani, K

    Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

    2023  Volume 2023, Page(s) 1–4

    Abstract: To achieve good treatment outcomes in coil embolization for cerebral aneurysms, it is important to select an appropriate 1st coil for each aneurysm since it serves as a frame to support the subsequent coils to be deployed. However, its selection as ... ...

    Abstract To achieve good treatment outcomes in coil embolization for cerebral aneurysms, it is important to select an appropriate 1st coil for each aneurysm since it serves as a frame to support the subsequent coils to be deployed. However, its selection as appropriate size and length from a wide variety of lineups is not easy, especially for inexperienced neurosurgeons. We developed a machine learning model (MLM) to predict the optimal size and length of the 1st coil by learning information on patients and aneurysms that were previously treated with coil embolization successfully. The accuracy rates of the MLM for the test data were 86.3% and 83.4% in the prediction of size and length, respectively. In addition, the accuracy rates for the 30 cases showed good prediction by the MLM when compared with two different skilled neurosurgeons. Although the accuracy rate of the well-experienced neurosurgeon is similar to MLM, the inexperienced neurosurgeon showed a worse rate and can benefit from the method.Clinical Relevance- The developed MLM has the potential to assist in the selection of the 1st coil for aneurysms. A technically and cost efficient supply chain in the treatment of aneurysms may also be achieved by MLM application.
    MeSH term(s) Humans ; Intracranial Aneurysm/diagnostic imaging ; Intracranial Aneurysm/therapy ; Embolization, Therapeutic/adverse effects ; Treatment Outcome ; Blood Vessel Prosthesis
    Language English
    Publishing date 2023-12-11
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 2694-0604
    ISSN (online) 2694-0604
    DOI 10.1109/EMBC40787.2023.10341191
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: A Novel Braided Stent With Customized Simulation Software for Treatment of Intracranial Aneurysms: Multicenter Prospective Trial Before Unrestricted Clinical Application.

    Kan, Issei / Oishi, Hidenori / Hyodo, Akio / Nemoto, Shigeru / Fujimura, Soichiro / Ishibashi, Toshihiro / Sumita, Kazutaka / Takigawa, Tomoji / Teranishi, Kohsuke / Kodama, Tomonobu / Kato, Naoki / Takao, Hiroyuki / Murayama, Yuichi

    Operative neurosurgery (Hagerstown, Md.)

    2023  Volume 26, Issue 2, Page(s) 180–187

    Abstract: Background and objectives: Planning/guidance software became important tools for physicians' presurgical optimal decision-making. However, there are no intracranial stent products with specifically associated simulation software. We report the " ... ...

    Abstract Background and objectives: Planning/guidance software became important tools for physicians' presurgical optimal decision-making. However, there are no intracranial stent products with specifically associated simulation software. We report the "premarket" clinical trial of a new braided stent with a customized simulation software.
    Methods: A stent system with 3 mesh density types (16, 24, and 32 wire mesh) was designed based on computational flow dynamics technology, and a simulation software (virtual stent planner [VSP]) was developed for the optimal stent deployment planning. Stents were selected after simulation on preoperative 3D-processed angioimages, and accuracy of the VSP was evaluated.
    Results: Thirty-three unruptured intracranial aneurysms were successfully treated with VSP guidance. Twenty aneurysms (61%) were anterior circulation aneurysms, and 13 (39%) were posterior circulation aneurysms. The average aneurysm size was 7.1 mm, and the mean follow-up period was 19.2 months (11-39.0). There was no major recurrence or retreatment during follow-up, 2 morbidity cases, and no mortality. VSP planning presented slightly smaller stent dimensions compared with postdeployment: 24.2 vs 25.5 mm average, error -1.3 mm, and difference rate-5.46%.
    Conclusion: Based on this result, the new stents and software guidance system were approved by the Ministry of Health and Welfare as a combined medical device. VSP provided precise deployment with minimal error compared with actual stent and can contribute to better stent deployment even for less experienced physicians.
    MeSH term(s) Humans ; Embolization, Therapeutic/methods ; Intracranial Aneurysm/diagnostic imaging ; Intracranial Aneurysm/surgery ; Prospective Studies ; Software ; Stents
    Language English
    Publishing date 2023-10-11
    Publishing country United States
    Document type Clinical Trial ; Journal Article ; Multicenter Study
    ZDB-ID 2767575-0
    ISSN 2332-4260 ; 2332-4252
    ISSN (online) 2332-4260
    ISSN 2332-4252
    DOI 10.1227/ons.0000000000000928
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Development of a Virtual Stent Deployment Application to Estimate Patient-Specific Braided Stent Sizes.

    Fujimura, Soichiro / Kan, Issei / Takao, Hiroyuki / Uchiyama, Yuya / Ishibashi, Toshihiro / Otani, Katharina / Fukudome, Koji / Murayama, Yuichi / Yamamoto, Makoto

    Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

    2021  Volume 2021, Page(s) 4184–4187

    Abstract: A virtual stent deployment application was developed to estimate the appropriate and patient-specific size of a braided stent for patients who undergo endovascular treatment for intracranial aneurysms. Comparing between the simulated deployed and the ... ...

    Abstract A virtual stent deployment application was developed to estimate the appropriate and patient-specific size of a braided stent for patients who undergo endovascular treatment for intracranial aneurysms. Comparing between the simulated deployed and the actual stents, we evaluated the accuracy of the simulation results. Our results indicated that lengths of the virtual and actual stents matched well despite the actual stent being affected by a geometrical change of the parent artery.Clinical Relevance-Surgeons need to be well-experienced to select an appropriate braided stent size for endovascular treatment of intracranial aneurysms, because the actual length of the deployed stent changes. This simulation will be helpful to make tailor-made surgical planning regardless of the surgeons' individual skill level.
    MeSH term(s) Computer Simulation ; Humans ; Intracranial Aneurysm/surgery ; Stents
    Language English
    Publishing date 2021-12-05
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 2694-0604
    ISSN (online) 2694-0604
    DOI 10.1109/EMBC46164.2021.9629928
    Database MEDical Literature Analysis and Retrieval System OnLINE

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