著者

Satoshi MAESAWA Epifanio BAGARINAO Masazumi FUJII Miyako FUTAMURA Toshihiko WAKABAYASHI

出版者

社団法人 日本脳神経外科学会

雑誌

Neurologia medico-chirurgica (ISSN:04708105)

巻号頁・発行日

pp.ra.2015-0302, (Released:2016-02-29)

参考文献数

81

被引用文献数

9

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Cutting-edge neuroimaging technologies can facilitate preoperative evaluation in various neurosurgical settings. Surgery for gliomas and epilepsy requires precise localization for resection due to the need to preserve (or perhaps improve) higher cognitive functions. Accordingly, a hodological approach should be taken that considers subcortical networks as well as cortical functions within various functional domains. Resting state functional magnetic resonance imaging (fMRI) has the potential to provide new insights that are valuable for this approach. In this review, we describe recent developments in network analysis using resting state fMRI related to factors in glioma and epilepsy surgery: the identification of functionally dominant areas, evaluation of cognitive function by alteration of resting state networks (RSNs), glioma grading, and epileptic focus detection. One particular challenge that is close to realization is using fMRI for the identification of sensorimotor- and language-dominant areas during a task-free resting state. Various RSNs representative of the default mode network demonstrated at least some alterations in both patient groups, which correlated with behavioral changes including cognition, memory, and attention, and the development of psychosis. Still challenging is the detection of epileptic foci and propagation pathways when using only network analysis with resting state fMRI; however, a combined method with simultaneous electroencephalography has produced promising results. Consequently, network analysis is expected to continue to advance as neuroimaging technology improves in the next decade, and preoperative evaluation for neurosurgical parameters through these techniques should improve parallel with them.

著者

Satoshi MAESAWA Epifanio BAGARINAO Daisuke NAKATSUBO Tomotaka ISHIZAKI Sou TAKAI Jun TORII Sachiko KATO Masashi SHIBATA Toshihiko WAKABAYASHI Ryuta SAITO

出版者

The Japan Neurosurgical Society

雑誌

Neurologia medico-chirurgica (ISSN:04708105)

巻号頁・発行日

vol.62, no.1, pp.45-55, 2022 (Released:2022-01-15)

参考文献数

31

被引用文献数

3

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Resting-state functional MRI (rs-fMRI) has been utilized to visualize large-scale brain networks. We evaluated the usefulness of multitier network analysis using rs-fMRI in patients with focal epilepsy. Structural and rs-fMRI data were retrospectively evaluated in 20 cases with medically refractory focal epilepsy, who subsequently underwent surgery. First, structural changes were examined using voxel-based morphometry analysis. Second, alterations in large-scale networks were evaluated using dual-regression analysis. Third, changes in cortical hubs were analyzed and the relationship between aberrant hubs and the epileptogenic zone (EZ) was evaluated. Finally, the relationship between the hubs and the default mode network (DMN) was examined using spectral dynamic causal modeling (spDCM). Dual-regression analysis revealed significant decrease in functional connectivity in several networks including DMN in patients, although no structural difference was seen between groups. Aberrant cortical hubs were observed in and around the EZ (EZ hubs) in 85% of the patients, and a strong degree of EZ hubs correlated to good seizure outcomes postoperatively. In spDCM analysis, facilitation was often seen from the EZ hub to the contralateral side, while inhibition was seen from the EZ hub to nodes of the DMN. Some cognition-related networks were impaired in patients with focal epilepsy. The EZ hub appeared in the vicinity of EZ facilitating connections to distant regions in the early phase, which may eventually generate secondary focus, while inhibiting connections to the DMN, which may cause cognitive deterioration. Our results demonstrate pathological network alterations in epilepsy and suggest that earlier surgical intervention may be more effective.

著者

Sanae Kato Epifanio Bagarinao Haruo Isoda Shuji Koyama Hirohisa Watanabe Satoshi Maesawa Daisuke Mori Kazuhiro Hara Masahisa Katsuno Minoru Hoshiyama Shinji Naganawa Norio Ozaki Gen Sobue

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.2020-0081, (Released:2020-10-27)

参考文献数

34

被引用文献数

4

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Purpose: The estimation of functional connectivity (FC) measures using resting state functional MRI (fMRI) is often affected by head motion during functional imaging scans. Head motion is more common in the elderly than in young participants and could therefore affect the evaluation of age-related changes in brain networks. Thus, this study aimed to investigate the influence of head motion in FC estimation when evaluating age-related changes in brain networks.Methods: This study involved 132 healthy volunteers divided into 3 groups: elderly participants with high motion (OldHM, mean age (±SD) = 69.6 (±5.31), N = 44), elderly participants with low motion (OldLM, mean age (±SD) = 68.7 (±4.59), N = 43), and young adult participants with low motion (YugLM, mean age (±SD) = 27.6 (±5.26), N = 45). Head motion was quantified using the mean of the framewise displacement of resting state fMRI data. After preprocessing all resting state fMRI datasets, several resting state networks (RSNs) were extracted using independent component analysis (ICA). In addition, several network metrics were also calculated using network analysis. These FC measures were then compared among the 3 groups.Results: In ICA, the number of voxels with significant differences in RSNs was higher in YugLM vs. OldLM comparison than in YugLM vs. OldHM. In network analysis, all network metrics showed significant (P < 0.05) differences in comparisons involving low vs. high motion groups (OldHM vs. OldLM and OldHM vs. YugLM). However, there was no significant (P > 0.05) difference in the comparison involving the low motion groups (OldLM vs. YugLM).Conclusion: Our findings showed that head motion during functional imaging could significantly affect the evaluation of age-related brain network changes using resting state fMRI data.

著者

Senda Joe Watanabe Hirohisa Endo Kuniyuki Yasui Keizo Hawsegawa Yasuhiro Yoneyama Noritaka Tsuboi Takashi Hara Kazuhiro Ito Mizuki Atsuta Naoki Epifanio Bagarinao Jr. Katsuno Masahisa Naganawa Shinji Sobue Gen

出版者

Nagoya University Graduate School of Medicine, School of Medicine

雑誌

Nagoya Journal of Medical Science (ISSN:00277622)

巻号頁・発行日

vol.78, no.4, pp.455-463, 2016-11

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Voxel-based analysis (VBA) of diffusion tensor images (DTI) and voxel-based morphometry (VBM) in patients with multiple sclerosis (MS) can sensitively detect occult tissue damage that underlies pathological changes in the brain. In the present study, both at the start of fingolimod and post-four months clinical remission, we assessed four patients with MS who were evaluated with VBA of DTI, VBM, and fluid-attenuated inversion recovery (FLAIR). DTI images for all four patients showed widespread areas of increased mean diffusivity (MD) and decreased fractional anisotropy (FA) that were beyond the highintensity signal areas across images. After four months of continuous fingolimod therapy, DTI abnormalities progressed; in particular, MD was significantly increased, while brain volume and high-intensity signals were unchanged. These findings suggest that VBA of DTI (e.g., MD) may help assess MS demyelination as neuroinflammatory conditions, even though clinical manifestations of MS appear to be in complete remission during fingolimod.