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  1. Article: Multi-agent system collision model to predict the transmission of seasonal influenza in Tokyo from 2014-2015 to 2018-2019 seasons.

    Tomizawa, Nobuo / Kumamaru, Kanako K / Okamoto, Koh / Aoki, Shigeki

    Heliyon

    2021  Volume 7, Issue 8, Page(s) e07859

    Abstract: The objective of this study was to apply the multi-agent system (MAS) collision model to predict seasonal influenza epidemic in Tokyo for 5 seasons (2014-2015 to 2018-2019 seasons). The MAS collision model assumes each individual as a particle inside a ... ...

    Abstract The objective of this study was to apply the multi-agent system (MAS) collision model to predict seasonal influenza epidemic in Tokyo for 5 seasons (2014-2015 to 2018-2019 seasons). The MAS collision model assumes each individual as a particle inside a square domain. The particles move within the domain and disease transmission occurs in a certain probability when an infected particle collides a susceptible particle. The probability was determined based on the basic reproduction number calculated using the actual data. The simulation started with 1 infected particle and 999 susceptible particles to correspond to the onset of an influenza epidemic. We performed the simulation for 150 days and the calculation was repeated 500 times for each season. To improve the accuracy of the prediction, we selected simulations which have similar incidence number to the actual data in specific weeks. Analysis including all simulations corresponded good to the actual data in 2014-2015 and 2015-2016 seasons. However, the model failed to predict the sharp peak incidence after the New Year Holidays in 2016-2017, 2017-2018, and 2018-2019 seasons. A model which included simulations selected by the week of peak incidence predicted the week and number of peak incidence better than a model including all simulations in all seasons. The reproduction number was also similar to the actual data in this model. In conclusion, the MAS collision model predicted the epidemic curve with good accuracy by selecting the simulations using the actual data without changing the initial parameters such as the basic reproduction number and infection time.
    Language English
    Publishing date 2021-08-23
    Publishing country England
    Document type Journal Article
    ZDB-ID 2835763-2
    ISSN 2405-8440
    ISSN 2405-8440
    DOI 10.1016/j.heliyon.2021.e07859
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Multi-agent system collision model to predict the transmission of seasonal influenza in Tokyo from 2014–2015 to 2018–2019 seasons

    Nobuo Tomizawa / Kanako K. Kumamaru / Koh Okamoto / Shigeki Aoki

    Heliyon, Vol 7, Iss 8, Pp e07859- (2021)

    2021  

    Abstract: The objective of this study was to apply the multi-agent system (MAS) collision model to predict seasonal influenza epidemic in Tokyo for 5 seasons (2014–2015 to 2018–2019 seasons). The MAS collision model assumes each individual as a particle inside a ... ...

    Abstract The objective of this study was to apply the multi-agent system (MAS) collision model to predict seasonal influenza epidemic in Tokyo for 5 seasons (2014–2015 to 2018–2019 seasons). The MAS collision model assumes each individual as a particle inside a square domain. The particles move within the domain and disease transmission occurs in a certain probability when an infected particle collides a susceptible particle. The probability was determined based on the basic reproduction number calculated using the actual data. The simulation started with 1 infected particle and 999 susceptible particles to correspond to the onset of an influenza epidemic. We performed the simulation for 150 days and the calculation was repeated 500 times for each season. To improve the accuracy of the prediction, we selected simulations which have similar incidence number to the actual data in specific weeks. Analysis including all simulations corresponded good to the actual data in 2014–2015 and 2015–2016 seasons. However, the model failed to predict the sharp peak incidence after the New Year Holidays in 2016–2017, 2017–2018, and 2018–2019 seasons. A model which included simulations selected by the week of peak incidence predicted the week and number of peak incidence better than a model including all simulations in all seasons. The reproduction number was also similar to the actual data in this model. In conclusion, the MAS collision model predicted the epidemic curve with good accuracy by selecting the simulations using the actual data without changing the initial parameters such as the basic reproduction number and infection time.
    Keywords Disease transmission ; Influenza ; Multi-agent system ; SIR model ; Science (General) ; Q1-390 ; Social sciences (General) ; H1-99
    Subject code 612
    Language English
    Publishing date 2021-08-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Coronary Artery Vorticity to Predict Functional Plaque Progression in Participants with Type 2 Diabetes Mellitus.

    Tomizawa, Nobuo / Fujimoto, Shinichiro / Mita, Tomoya / Takahashi, Daigo / Nozaki, Yui / Fan, Ruiheng / Kudo, Ayako / Kawaguchi, Yuko / Takamura, Kazuhisa / Hiki, Makoto / Kurita, Mika / Kumamaru, Kanako K / Watada, Hirotaka / Minamino, Tohru / Aoki, Shigeki

    Radiology. Cardiothoracic imaging

    2023  Volume 5, Issue 4, Page(s) e230016

    Abstract: Purpose: To investigate whether vorticity could predict functional plaque progression better than high-risk plaque (HRP) and lesion length (LL) in individuals with type 2 diabetes mellitus.: Materials and methods: This single-center prospective study ...

    Abstract Purpose: To investigate whether vorticity could predict functional plaque progression better than high-risk plaque (HRP) and lesion length (LL) in individuals with type 2 diabetes mellitus.
    Materials and methods: This single-center prospective study included 61 participants (mean age, 61 years ± 9 [SD]; 43 male participants) who underwent serial coronary CT angiography at 2 years, with 20%-70% stenosis at initial CT between October 2015 and March 2020. The number of the following HRP characteristics was recorded: low attenuation, positive remodeling, spotty calcification, and napkin-ring sign. Vorticity was calculated using a mesh-free simulation. A decrease in CT fractional flow reserve larger than 0.05 indicated functional progression. Models using HRP and LL and vorticity were compared using receiver operating characteristic curve analysis.
    Results: Of the 94 vessels evaluated, 25 vessels (27%) showed functional progression. Vessels with functional progression showed higher vorticity at distal stenosis (984 sec
    Conclusion: In participants with type 2 diabetes mellitus, vorticity at distal stenosis was a better predictor of functional plaque progression than HRP and LL.
    Language English
    Publishing date 2023-08-24
    Publishing country United States
    Document type Journal Article
    ISSN 2638-6135
    ISSN (online) 2638-6135
    DOI 10.1148/ryct.230016
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Energy loss is related to CT fractional flow reserve progression in type 2 diabetes mellitus patients.

    Tomizawa, Nobuo / Fujimoto, Shinichiro / Takahashi, Daigo / Nozaki, Yui / Fan, Ruiheng / Kudo, Ayako / Kawaguchi, Yuko / Takamura, Kazuhisa / Hiki, Makoto / Kadowaki, Satoshi / Ikeda, Fuki / Kumamaru, Kanako K / Watada, Hirotaka / Minamino, Tohru / Aoki, Shigeki

    American heart journal plus : cardiology research and practice

    2023  Volume 35, Page(s) 100328

    Abstract: Background: We aimed to investigate the diagnostic value of energy loss (EL) and baseline CT fractional flow reserve (CT-FFR) computed using computational fluid dynamics to predict functional progression of coronary stenosis in patients with type 2 ... ...

    Abstract Background: We aimed to investigate the diagnostic value of energy loss (EL) and baseline CT fractional flow reserve (CT-FFR) computed using computational fluid dynamics to predict functional progression of coronary stenosis in patients with type 2 diabetes mellitus.
    Methods: This single-center prospective study included 61 patients with type 2 diabetes mellitus (mean age, 61 years ±9 [SD]; 43 men) showing 20-70 % stenosis who underwent serial coronary CT performed at 2-year interval between October 2015 and March 2020. A mesh-free simulation was performed to calculate the CT-FFR and EL. Functional progression was defined as ≥ 0.05 decrease in CT-FFR on the second coronary CT. Models using baseline CT-FFR and EL were compared by analyzing the receiver operating characteristic (ROC) curve.
    Results: Of the 94 vessels evaluated, 25 vessels (27 %) showed functional progression. EL at distal stenosis (EL
    Conclusion: When EL
    Language English
    Publishing date 2023-09-28
    Publishing country United States
    Document type Journal Article
    ISSN 2666-6022
    ISSN (online) 2666-6022
    DOI 10.1016/j.ahjo.2023.100328
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Validation and clinical impact of novel pericoronary adipose tissue measurement on ECG-gated non-contrast chest CT.

    Takahashi, Daigo / Fujimoto, Shinichiro / Nozaki, Yui O / Kudo, Ayako / Kawaguchi, Yuko O / Takamura, Kazuhisa / Hiki, Makoto / Sato, Hideyuki / Tomizawa, Nobuo / Kumamaru, Kanako K / Aoki, Shigeki / Minamino, Tohru

    Atherosclerosis

    2023  Volume 370, Page(s) 18–24

    Abstract: Background and aims: We aimed to develop a method for quantifying pericoronary adipose tissue (PCAT) on electrocardiogram (ECG)-gated non-contrast CT (NC-PCAT) and validate its efficacy and prognostic value.: Methods: We retrospectively studied two ... ...

    Abstract Background and aims: We aimed to develop a method for quantifying pericoronary adipose tissue (PCAT) on electrocardiogram (ECG)-gated non-contrast CT (NC-PCAT) and validate its efficacy and prognostic value.
    Methods: We retrospectively studied two independent cohorts. PCAT was quantified conventionally. NC-PCAT was defined as the mean CT value of epicardial fat tissue adjacent to right coronary artery ostium on ECG-gated non-contrast CT. In cohort 1 (n = 300), we evaluated the correlation of two methods and the association between NC-PCAT and CT-verified high-risk plaque (HRP). We dichotomized cohort 2 (n = 333) by the median of NC-PCAT, and assessed the prognostic value of NC-PCAT for primary endpoint (all-cause death and non-fatal myocardial infarction) by Cox regression analysis. The median duration of follow-up was 2.9 years.
    Results: NC-PCAT was correlated with PCAT (r = 0.68, p<0.0001). In multivariable logistic regression analysis, high NC-PCAT (OR:1.06; 95%CI:1.03-1.10; p = 0.0001), coronary artery calcium score (CACS) (OR:1.01 per 10 CACS increase, 95%CI:1.00-1.02; p = 0.013), and current smoking (OR:2.58; 95%CI:1.03-6.49; p = 0.044) were independent predictors of HRP. Among patients with CACS>0 (n = 193), NC-PCAT (OR:1.06; 95%CI:1.03-1.10; p = 0.0002), current smoking (OR:3.02; 95%CI:1.17-7.82; p = 0.027), and male sex (OR:2.81; 95%CI:1.06-7.48; p = 0.028) were independent predictors of HRP, whereas CACS was not (p = 0.15). Multivariable Cox regression analysis revealed high NC-PCAT as an independent predictor of the primary endpoint, even after adjustment for sex and age (HR:4.3; 95%CI:1.2-15.2; p = 0.012).
    Conclusions: There was a positive correlation between NC-PCAT and PCAT, with high NC-PCAT significantly associated with worse clinical outcome (independent of CACS) as well as presence of HRP.
    MeSH term(s) Humans ; Male ; Coronary Artery Disease/diagnostic imaging ; Coronary Angiography/methods ; Retrospective Studies ; Tomography, X-Ray Computed/methods ; Plaque, Atherosclerotic ; Adipose Tissue/diagnostic imaging ; Electrocardiography ; Computed Tomography Angiography/methods ; Coronary Vessels/diagnostic imaging
    Language English
    Publishing date 2023-01-31
    Publishing country Ireland
    Document type Journal Article
    ZDB-ID 80061-2
    ISSN 1879-1484 ; 0021-9150
    ISSN (online) 1879-1484
    ISSN 0021-9150
    DOI 10.1016/j.atherosclerosis.2023.01.021
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Development and Validation of a Modified Three-Dimensional U-Net Deep-Learning Model for Automated Detection of Lung Nodules on Chest CT Images From the Lung Image Database Consortium and Japanese Datasets.

    Suzuki, Kazuhiro / Otsuka, Yujiro / Nomura, Yukihiro / Kumamaru, Kanako K / Kuwatsuru, Ryohei / Aoki, Shigeki

    Academic radiology

    2020  Volume 29 Suppl 2, Page(s) S11–S17

    Abstract: Rationale and objectives: A more accurate lung nodule detection algorithm is needed. We developed a modified three-dimensional (3D) U-net deep-learning model for the automated detection of lung nodules on chest CT images. The purpose of this study was ... ...

    Abstract Rationale and objectives: A more accurate lung nodule detection algorithm is needed. We developed a modified three-dimensional (3D) U-net deep-learning model for the automated detection of lung nodules on chest CT images. The purpose of this study was to evaluate the accuracy of the developed modified 3D U-net deep-learning model.
    Materials and methods: In this Health Insurance Portability and Accountability Act-compliant, Institutional Review Board-approved retrospective study, the 3D U-net based deep-learning model was trained using the Lung Image Database Consortium and Image Database Resource Initiative dataset. For internal model validation, we used 89 chest CT scans that were not used for model training. For external model validation, we used 450 chest CT scans taken at an urban university hospital in Japan. Each case included at least one nodule of >5 mm identified by an experienced radiologist. We evaluated model accuracy using the competition performance metric (CPM) (average sensitivity at 1/8, 1/4, 1/2, 1, 2, 4, and 8 false-positives per scan). The 95% confidence interval (CI) was computed by bootstrapping 1000 times.
    Results: In the internal validation, the CPM was 94.7% (95% CI: 89.1%-98.6%). In the external validation, the CPM was 83.3% (95% CI: 79.4%-86.1%).
    Conclusion: The modified 3D U-net deep-learning model showed high performance in both internal and external validation.
    MeSH term(s) Deep Learning ; Humans ; Japan ; Lung/diagnostic imaging ; Lung Neoplasms/diagnostic imaging ; Retrospective Studies ; Tomography, X-Ray Computed/methods
    Language English
    Publishing date 2020-08-21
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1355509-1
    ISSN 1878-4046 ; 1076-6332
    ISSN (online) 1878-4046
    ISSN 1076-6332
    DOI 10.1016/j.acra.2020.07.030
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Multi-agent system collision model to predict the transmission of seasonal influenza in Tokyo from 2014–2015 to 2018–2019 seasons

    Tomizawa, Nobuo / Kumamaru, Kanako K. / Okamoto, Koh / Aoki, Shigeki

    Heliyon. 2021 Aug., v. 7, no. 8

    2021  

    Abstract: The objective of this study was to apply the multi-agent system (MAS) collision model to predict seasonal influenza epidemic in Tokyo for 5 seasons (2014–2015 to 2018–2019 seasons). The MAS collision model assumes each individual as a particle inside a ... ...

    Abstract The objective of this study was to apply the multi-agent system (MAS) collision model to predict seasonal influenza epidemic in Tokyo for 5 seasons (2014–2015 to 2018–2019 seasons). The MAS collision model assumes each individual as a particle inside a square domain. The particles move within the domain and disease transmission occurs in a certain probability when an infected particle collides a susceptible particle. The probability was determined based on the basic reproduction number calculated using the actual data. The simulation started with 1 infected particle and 999 susceptible particles to correspond to the onset of an influenza epidemic. We performed the simulation for 150 days and the calculation was repeated 500 times for each season. To improve the accuracy of the prediction, we selected simulations which have similar incidence number to the actual data in specific weeks. Analysis including all simulations corresponded good to the actual data in 2014–2015 and 2015–2016 seasons. However, the model failed to predict the sharp peak incidence after the New Year Holidays in 2016–2017, 2017–2018, and 2018–2019 seasons. A model which included simulations selected by the week of peak incidence predicted the week and number of peak incidence better than a model including all simulations in all seasons. The reproduction number was also similar to the actual data in this model. In conclusion, the MAS collision model predicted the epidemic curve with good accuracy by selecting the simulations using the actual data without changing the initial parameters such as the basic reproduction number and infection time.
    Keywords basic reproduction number ; influenza ; models ; prediction ; probability ; reproduction
    Language English
    Dates of publication 2021-08
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 2835763-2
    ISSN 2405-8440
    ISSN 2405-8440
    DOI 10.1016/j.heliyon.2021.e07859
    Database NAL-Catalogue (AGRICOLA)

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  8. Article ; Online: Coronary flow disturbance assessed by vorticity as a cause of functionally significant stenosis.

    Tomizawa, Nobuo / Nozaki, Yui / Fujimoto, Shinichiro / Takahashi, Daigo / Kudo, Ayako / Kamo, Yuki / Aoshima, Chihiro / Kawaguchi, Yuko / Takamura, Kazuhisa / Hiki, Makoto / Dohi, Tomotaka / Okazaki, Shinya / Kumamaru, Kanako K / Minamino, Tohru / Aoki, Shigeki

    European radiology

    2022  Volume 32, Issue 10, Page(s) 6859–6867

    Abstract: Objectives: Vorticity calculated using computational fluid dynamics (CFD) could assess the flow disturbance generated by coronary stenosis. The purpose of this study was to investigate whether vorticity would be an underlying cause of functionally ... ...

    Abstract Objectives: Vorticity calculated using computational fluid dynamics (CFD) could assess the flow disturbance generated by coronary stenosis. The purpose of this study was to investigate whether vorticity would be an underlying cause of functionally significant stenosis assessed by invasive fractional flow reserve (FFR).
    Methods: This retrospective study included 113 patients who underwent coronary CT angiography showing intermediate stenosis and subsequent invasive FFR between December 2015 and March 2020. Vorticity at the stenosis site was calculated using a mesh-free CFD method. We also evaluated the minimum lumen area (MLA) and diameter stenosis (DS) of the lesion. Invasive FFR of ≤ 0.80 was considered functionally significant. Data were compared using Student's t-test and logistic regression analysis was performed.
    Results: Of the evaluated 144 vessels, 53 vessels (37%) showed FFR ≤ 0.80. Vorticity of significant stenosis was significantly higher than non-significant stenosis (569 ± 78 vs. 328 ± 34 s
    Conclusions: Vorticity had a statistically significant negative relationship with invasive FFR independent of geometric stenosis.
    Key points: • Flow disturbance caused by coronary stenosis could be evaluated by calculating vorticity which is defined as the norm of the rotation of the velocity vector. • Vorticity was statistically significantly higher in stenosis with functional significance than stenosis without. • Vorticity has an additive value to detect functionally significant stenosis over geometrical stenosis.
    MeSH term(s) Constriction, Pathologic/pathology ; Coronary Angiography/methods ; Coronary Stenosis/diagnosis ; Coronary Vessels ; Fractional Flow Reserve, Myocardial ; Humans ; Predictive Value of Tests ; Retrospective Studies ; Severity of Illness Index
    Language English
    Publishing date 2022-07-02
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 1085366-2
    ISSN 1432-1084 ; 0938-7994 ; 1613-3749
    ISSN (online) 1432-1084
    ISSN 0938-7994 ; 1613-3749
    DOI 10.1007/s00330-022-08974-2
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Correction to: Global and Japanese regional variations in radiologist potential workload for computed tomography and magnetic resonance imaging examinations.

    Kumamaru, Kanako K / Machitori, Akihiro / Koba, Ritsuko / Ijichi, Shinpei / Nakajima, Yasuo / Aoki, Shigeki

    Japanese journal of radiology

    2018  Volume 36, Issue 4, Page(s) 282–284

    Abstract: In Results of Abstract, the first sentence should read as: The radiologist potential workload in Japan was 2.78-4.17 times higher than those in other countries. ...

    Abstract In Results of Abstract, the first sentence should read as: The radiologist potential workload in Japan was 2.78-4.17 times higher than those in other countries.
    Language English
    Publishing date 2018-03-20
    Publishing country Japan
    Document type Published Erratum
    ZDB-ID 2488907-6
    ISSN 1867-108X ; 1867-1071
    ISSN (online) 1867-108X
    ISSN 1867-1071
    DOI 10.1007/s11604-018-0730-7
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: A National Survey on Safety Management at MR Imaging Facilities in Japan.

    Azuma, Minako / Kumamaru, Kanako K / Hirai, Toshinori / Khant, Zaw Aung / Koba, Ritsuko / Ijichi, Shinpei / Jinzaki, Masahiro / Murayama, Sadayuki / Aoki, Shigeki

    Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine

    2020  Volume 20, Issue 4, Page(s) 347–358

    Abstract: Purpose: To investigate safety management at Japanese facilities performing human MRI studies.: Methods: All Japanese facilities performing human MRI studies were invited to participate in a comprehensive survey that evaluated their MRI safety ... ...

    Abstract Purpose: To investigate safety management at Japanese facilities performing human MRI studies.
    Methods: All Japanese facilities performing human MRI studies were invited to participate in a comprehensive survey that evaluated their MRI safety management. The survey used a questionnaire prepared with the cooperation of the Safety Committee of the Japanese Society for Magnetic Resonance in Medicine. The survey addressed items pertaining to the overall MRI safety management, questions on the occurrence of incidents, and questions specific to facility and MRI scanner or examination. The survey covered the period from October 2017 to September 2018. Automated machine learning was used to identify factors associated with major incidents.
    Results: Of 5914 facilities, 2015 (34%) responded to the questionnaire. There was a wide variation in the rate of compliance with MRI safety management items among the participating facilities. Among the facilities responding to this questionnaire, 5% reported major incidents and 27% reported minor incidents related to MRI studies. Most major incidents involved the administration of contrast agents. The most influential factor in major incidents was the total number of MRI studies performed at the facility; this number was significantly correlated with the risk of major incidents (P < 0.0001).
    Conclusion: There were large variations in the safety standards applied at Japanese facilities performing clinical MRI studies. The total number of MRI studies performed at a facility affected the number of major incidents.
    MeSH term(s) Contrast Media ; Humans ; Japan ; Magnetic Resonance Imaging ; Safety Management ; Surveys and Questionnaires
    Chemical Substances Contrast Media
    Language English
    Publishing date 2020-11-26
    Publishing country Japan
    Document type Journal Article
    ZDB-ID 2217833-8
    ISSN 1880-2206 ; 1880-2206
    ISSN (online) 1880-2206
    ISSN 1880-2206
    DOI 10.2463/mrms.mp.2020-0084
    Database MEDical Literature Analysis and Retrieval System OnLINE

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