著者

Ryota Sakurai Hisashi Kawai Hiroyuki Suzuki Susumu Ogawa Hunkyung Kim Yutaka Watanabe Hirohiko Hirano Kazushige Ihara Shuichi Obuchi Yoshinori Fujiwara

出版者

Japan Epidemiological Association

雑誌

Journal of Epidemiology (ISSN:09175040)

巻号頁・発行日

pp.JE20180162, (Released:2018-12-08)

参考文献数

12

被引用文献数

2 2

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Background: Considering the rate of growth of the older population in several countries, accidental falls in older cyclists are expected to increase. However, the prevalence and correlates of bicycle-related falls (BR-falls) are unknown. The aim of the present study was to explore the characteristics of BR-falls, focusing on the risk factors.Methods: Seven-hundred and ninety-one older adults participated in a comprehensive baseline assessment that included questions on bicycle use, BR-falls, lifestyle, and physical and cognitive evaluations. A cyclist was defined as a person who cycled at least a few times per month. The incidence of BR-falls in participants who did not report BR-falls at baseline was again ascertained 3 years later. Logistic regression analyses examined the predictors of BR-falls incidence.Results: At baseline, 395 older adults were cyclists and 45 (11.4%) of them had experienced BR-falls. Adjusted regression analysis showed that slower gait velocity, shorter one-leg standing time, and experience of falls (ie, non-BR-falls) were associated with BR-falls. Among the 214 cyclists who did not report BR-falls at baseline and who participated in both baseline and follow-up assessments, 35 (16.4%) cyclists experienced BR-falls during the 3-year follow-up. Adjusted regression analysis revealed that higher body mass index and non-BR-falls were predictors of future incidence of BR-falls, independent of physical function.Conclusions: Our results showed that experience of falls, irrespective of bicycling, is an independent correlate and risk factor of BR-falls. This suggests that experience of falls and BR-falls may share the same risk factors.

著者

Shinji Naganawa Toshiki Nakane Hisashi Kawai Toshiaki Taoka Hirokazu Kawaguchi Katsuya Maruyama Katsutoshi Murata Gregor Körzdörfer Josef Pfeuffer Mathias Nittka Michihiko Sone

出版者

Japanese Society for Magnetic Resonance in Medicine

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.mp.2019-0048, (Released:2019-06-20)

参考文献数

31

被引用文献数

14

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Purpose: It has been reported that leakage of intravenously administered gadolinium-based contrast agents (IV-GBCAs) into the cerebrospinal fluid (CSF) from the cortical veins even in healthy subjects can be detected using a highly sensitive pulse sequence such as heavily T2-weighted 3D fluid-attenuated inversion recovery and 3D-real inversion recovery (IR). The purpose of this study was to evaluate the feasibility of MR fingerprinting to detect GBCA leakage from the cortical veins after IV-GBCA.Materials: Fourteen patients with suspected endolymphatic hydrops (EH) who received a single dose of IV-GBCA (39–79 years old) were included. The real IR images as well as MR fingerprinting images were obtained at 4 h after IV-GBCA. T1 and T2 values were obtained using MR fingerprinting and analyzed in ROIs covering intense GBCA leakage, and non-leakage areas of the CSF as determined on real IR images. The scan time for real IR imaging was 10 min and that for MR fingerprinting was 41 s.Results: The mean T1 value of the ROI in the area of GBCA leakage was 2422 ± 261 ms and that in the non-leakage area was 3851 ± 235 ms (P < 0.01). There was no overlap between the T1 values in the area of GBCA leakage and those in the non-leakage area.The mean T2 value in the area of GBCA leakage was 319 ± 90 ms and that in the non-leakage area was 670 ± 166 ms (P < 0.01). There was some overlap between the T2 values in the area of GBCA leakage and those in the non-leakage area.Conclusion: Leaked GBCA from the cortical veins into the surrounding CSF can be detected using MR fingerprinting obtained in <1 min.

著者

Keisuke Matsubara Takuma Okamoto Ryoichi Takashima Tetsuya Takiguchi Tomoki Toda Hisashi Kawai

出版者

ACOUSTICAL SOCIETY OF JAPAN

雑誌

Acoustical Science and Technology (ISSN:13463969)

巻号頁・発行日

vol.43, no.2, pp.121-124, 2022-03-01 (Released:2022-03-01)

参考文献数

16

被引用文献数

3

著者

Keisuke Matsubara Takuma Okamoto Ryoichi Takashima Tetsuya Takiguchi Tomoki Toda Yoshinori Shiga Hisashi Kawai

出版者

ACOUSTICAL SOCIETY OF JAPAN

雑誌

Acoustical Science and Technology (ISSN:13463969)

巻号頁・発行日

vol.42, no.1, pp.65-68, 2021-01-01 (Released:2021-01-01)

参考文献数

19

被引用文献数

6

著者

Shinji Naganawa Toshiki Nakane Hisashi Kawai Toshiaki Taoka

出版者

Japanese Society for Magnetic Resonance in Medicine

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.mp.2017-0137, (Released:2018-01-18)

参考文献数

28

被引用文献数

16

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Purpose: To elucidate differences between the perivascular space (PVS) in the basal ganglia (BG) versus that found in white matter (WM) using heavily T2-weighted FLAIR (hT2-FL) in terms of 1) signal intensity on non-contrast enhanced images, and 2) the degree of contrast enhancement by intravenous single dose administration of gadolinium based contrast agent (IV-SD-GBCA).Materials and Methods: Eight healthy men and 13 patients with suspected endolymphatic hydrops were included. No subjects had renal insufficiency. All subjects received IV-SD-GBCA. MR cisternography (MRC) and hT2-FL images were obtained prior to and 4 h after IV-SD-GBCA. The signal intensity of the PVS in the BG, subinsular WM, and the cerebrospinal fluid (CSF) in Ambient cistern (CSFAC) and CSF in Sylvian fissure (CSFSyl) was measured as well as that of the thalamus. The signal intensity ratio (SIR) was calculated by dividing the intensity by that of the thalamus. We used 5% as a threshold to determine the significance of the statistical test.Results: In the pre-contrast scan, the SIR of the PVS in WM (Mean ± standard deviation, 1.83 ± 0.46) was significantly higher than that of the PVS in the BG (1.05 ± 0.154), CSFSyl (1.03 ± 0.15) and the CSFAC (0.97 ± 0.29). There was no significant difference between the SIR of the PVS in the BG compared to the CSFAC and CSFSyl. For the evaluation of the contrast enhancement effect, significant enhancement was observed in the PVS in the BG, the CSFAC and the CSFSyl compared to the pre-contrast scan. No significant contrast enhancement was observed in the PVS in WM.Conclusion: The signal intensity difference between the PVS in the BG versus WM on pre-contrast images suggests that the fluid composition might be different between these PVSs. The difference in the contrast enhancement between the PVSs in the BG versus WM suggests a difference in drainage function.

著者

Ryota Sakurai Hisashi Kawai Hideyo Yoshida Taro Fukaya Hiroyuki Suzuki Hunkyung Kim Hirohiko Hirano Kazushige Ihara Shuichi Obuchi Yoshinori Fujiwara

出版者

日本疫学会

雑誌

Journal of Epidemiology (ISSN:09175040)

巻号頁・発行日

pp.JE20150017, (Released:2016-02-20)

参考文献数

28

被引用文献数

20

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Background: The health benefits of bicycling in older adults with mobility limitation (ML) are unclear. We investigated ML and functional capacity of older cyclists by evaluating their instrumental activities of daily living (IADL), intellectual activity, and social function.Methods: On the basis of interviews, 614 community-dwelling older adults (after excluding 63 participants who never cycled) were classified as cyclists with ML, cyclists without ML, non-cyclists with ML (who ceased bicycling due to physical difficulties), or non-cyclists without ML (who ceased bicycling for other reasons). A cyclist was defined as a person who cycled at least a few times per month, and ML was defined as difficulty walking 1 km or climbing stairs without using a handrail. Functional capacity and physical ability were evaluated by standardized tests.Results: Regular cycling was documented in 399 participants, and 74 of them (18.5%) had ML; among non-cyclists, 49 had ML, and 166 did not. Logistic regression analysis for evaluating the relationship between bicycling and functional capacity revealed that non-cyclists with ML were more likely to have reduced IADL and social function compared to cyclists with ML. However, logistic regression analysis also revealed that the risk of bicycle-related falls was significantly associated with ML among older cyclists.Conclusions: The ability and opportunity to bicycle may prevent reduced IADL and social function in older adults with ML, although older adults with ML have a higher risk of falls during bicycling. It is important to develop a safe environment for bicycling for older adults.

著者

Toshiaki Taoka Rintaro Ito Rei Nakamichi Toshiki Nakane Hisashi Kawai Shinji Naganawa

出版者

Japanese Society for Magnetic Resonance in Medicine

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.rev.2022-0012, (Released:2022-11-25)

参考文献数

115

被引用文献数

8

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Interest in interstitial fluid dynamics has increased since the proposal of the glymphatic system hypothesis. Abnormal dynamics of the interstitial fluid have been pointed out to be an important factor in various pathological statuses. In this article, we propose the concept of central nervous system interstitial fluidopathy as a disease or condition in which abnormal interstitial fluid dynamics is one of the important factors for the development of a pathological condition. We discuss the aspects of interstitial fluidopathy in various diseases, including Alzheimer’s disease, Parkinson’s disease, normal pressure hydrocephalus, and cerebral small vessel disease. We also discuss a method called “diffusion tensor image analysis along the perivascular space” using MR diffusion images, which is used to evaluate the degree of interstitial fluidopathy or the activity of the glymphatic system.

著者

Shinji Naganawa Rintaro Ito Hisashi Kawai Mariko Kawamura Toshiaki Taoka Tadao Yoshida Michihiko Sone

出版者

Japanese Society for Magnetic Resonance in Medicine

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.mp.2021-0010, (Released:2021-04-24)

参考文献数

36

被引用文献数

1

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Purpose: To evaluate the relationship between the size of the venous structures related to the inner ear and the degree of endolymphatic hydrops (EH).Methods: Thirty-four patients with a suspicion of EH underwent whole brain MR imaging including the inner ear. Images were obtained pre- and post-administration, and at 4 and 24 hours after the intravenous administration of a gadolinium-based contrast agent (IV-GBCA). The cross-sectional areas (CSA) of the internal jugular vein (IJV), superior petrosal sinus (SPS), and inferior petrosal sinus (IPS) were measured on the magnetization prepared rapid acquisition of gradient echo (MPRAGE) images obtained immediately after the IV-GBCA. The grade of EH was determined on the hybrid of reversed image of positive endolymph signal and native image of positive perilymph signal (HYDROPS) images obtained at 4 hours after IV-GBCA as no, mild, and significant EH according to the previously proposed grading system for the cochlea and vestibule, respectively. The ipsilateral CSA was compared between groups with each level of EH grade. P < 0.05 was considered statistically significant.Results: There were no statistically significant differences between EH grades for the CSA of the IJV or that of the IPS in either the cochlea or the vestibule. The CSA of the SPS in the groups with significant EH was significantly smaller than that in the group with no EH, for both the cochlea (P < 0.01) and the vestibule (P < 0.05). In an ROC analysis to predict significant EH, the cut-off CSA value in the SPS was 3.905 mm2 for the cochlea (AUC: 0.8762, 95% confidence interval [CI]: 0.7952‒0.9572) and 3.805 mm2 for the vestibule (AUC: 0.7727, 95% CI: 0.6539‒0.8916).Conclusion: In the ears with significant EH in the cochlea or vestibule, the CSA of the ipsilateral SPS was smaller than in the ears without EH.

著者

Shinji Naganawa Rintaro Ito Hisashi Kawai Mariko Kawamura Toshiaki Taoka Mayuko Sakai Kazushige Ichikawa Tadao Yoshida Michihiko Sone

出版者

Japanese Society for Magnetic Resonance in Medicine

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.ici.2021-0022, (Released:2021-04-24)

参考文献数

12

被引用文献数

7

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In this study, we present images acquired by a fast-imaging method for the evaluation of endolymphatic hydrops after intravenous administration of a single dose of gadolinium-based contrast agent. We utilized the hybrid of reversed image of MR cisternography and a positive perilymph signal by heavily T2- weighted 3D-fluid attenuated inversion recovery-multiplied by T2 (HYDROPS2-Mi2) method combined with deep learning reconstruction denoising. The scan time for the fast protocol was approximately 5 mins, which is far shorter than previously reported scan times. The fast acquisition provides similar image quality and less motion artifacts compared to the longer method.

著者

Takuma Okamoto Kentaro Tachibana Tomoki Toda Yoshinori Shiga Hisashi Kawai

出版者

ACOUSTICAL SOCIETY OF JAPAN

雑誌

Acoustical Science and Technology (ISSN:13463969)

巻号頁・発行日

vol.39, no.2, pp.163-166, 2018-03-01 (Released:2018-03-01)

参考文献数

13

被引用文献数

8

著者

Shinji Naganawa Toshiaki Taoka Hisashi Kawai Masahiro Yamazaki Kojiro Suzuki

出版者

日本磁気共鳴医学会

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.mp.2017-0088, (Released:2017-09-29)

参考文献数

31

被引用文献数

9

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Purpose: Circumventricular organs (CVOs) lack a blood brain barrier and are also called “brain windows”. Among CVOs, the organum vasculosum of the lamina terminalis (OVLT) is an osmotic regulator involved in the release of vasopressin. In a previous study of healthy subjects, it was reported that contrast enhancement in the OVLT can be recognized in only 34% of 3 Tesla thin slice contrast-enhanced T1-weighted images. The purpose of this study was to evaluate the leakage of gadolinium contrast from the OVLT in healthy subjects using heavily T2-weighted three dimensional-fluid attenuated inversion recovery (3D-FLAIR) (HF) imaging.Methods: Eight healthy male subjects were included in this study. A standard dose (0.1 mmol/kg) of gadoteridol was intravenously administered. magnetic resonance cisternography (MRC) and HF were obtained before and 0.5, 1.5, 3, 4.5 and 6 h after the injection. Enhancement of the OVLT including the surrounding cerebral spinal fluid (CSF) was measured by manually drawing a rectangular region of interest (ROI) centered on the OVLT. The ROI was copied to the HF image and the signal intensity was measured. The signal intensity ratio (SIR) was obtained by dividing the signal intensity value of the OVLT ROI by that of the midbrain.Results: The differences between the mean SIR at pre-contrast and those at 0.5, 1.5, 3, 4.5, and 6 h were significant (P < 0.05). The mean SIR at 0.5 h was higher than those at all other time points (P < 0.05).Conclusion: Using HF imaging, enhancement around the OVLT was observed in all subjects at 0.5 h after intravenous administration of single dose gadoteridol.

著者

Shigeki MATSUDA Teruaki HAYASHI Yutaka ASHIKARI Yoshinori SHIGA Hidenori KASHIOKA Keiji YASUDA Hideo OKUMA Masao UCHIYAMA Eiichiro SUMITA Hisashi KAWAI Satoshi NAKAMURA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Information and Systems (ISSN:09168532)

巻号頁・発行日

vol.E100-D, no.4, pp.621-632, 2017-04-01

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This study introduces large-scale field experiments of VoiceTra, which is the world's first speech-to-speech multilingual translation application for smart phones. In the study, approximately 10 million input utterances were collected since the experiments commenced. The usage of collected data was analyzed and discussed. The study has several important contributions. First, it explains system configuration, communication protocol between clients and servers, and details of multilingual automatic speech recognition, multilingual machine translation, and multilingual speech synthesis subsystems. Second, it demonstrates the effects of mid-term system updates using collected data to improve an acoustic model, a language model, and a dictionary. Third, it analyzes system usage.

著者

Ryota Sakurai Hisashi Kawai Hideyo Yoshida Taro Fukaya Hiroyuki Suzuki Hunkyung Kim Hirohiko Hirano Kazushige Ihara Shuichi Obuchi Yoshinori Fujiwara

出版者

日本疫学会

雑誌

Journal of Epidemiology (ISSN:09175040)

巻号頁・発行日

vol.26, no.6, pp.307-314, 2016-06-05 (Released:2016-06-05)

参考文献数

28

被引用文献数

20

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Background: The health benefits of bicycling in older adults with mobility limitation (ML) are unclear. We investigated ML and functional capacity of older cyclists by evaluating their instrumental activities of daily living (IADL), intellectual activity, and social function.Methods: On the basis of interviews, 614 community-dwelling older adults (after excluding 63 participants who never cycled) were classified as cyclists with ML, cyclists without ML, non-cyclists with ML (who ceased bicycling due to physical difficulties), or non-cyclists without ML (who ceased bicycling for other reasons). A cyclist was defined as a person who cycled at least a few times per month, and ML was defined as difficulty walking 1 km or climbing stairs without using a handrail. Functional capacity and physical ability were evaluated by standardized tests.Results: Regular cycling was documented in 399 participants, and 74 of them (18.5%) had ML; among non-cyclists, 49 had ML, and 166 did not. Logistic regression analysis for evaluating the relationship between bicycling and functional capacity revealed that non-cyclists with ML were more likely to have reduced IADL and social function compared to cyclists with ML. However, logistic regression analysis also revealed that the risk of bicycle-related falls was significantly associated with ML among older cyclists.Conclusions: The ability and opportunity to bicycle may prevent reduced IADL and social function in older adults with ML, although older adults with ML have a higher risk of falls during bicycling. It is important to develop a safe environment for bicycling for older adults.