Details of a Researcher

Papers - ENATSU Rei

Division display 1 - 20 of about 228 ／ All the affair displays >>

Clinical significance of intraoperative bidirectional corticocortical evoked potential monitoring to evaluate language function.

Chie Kamada, Yusuke Kimura, Shoto Yamada, Ryohei Saito, Katsuya Komatsu, Rei Enatsu, Yukinori Akiyama, Nobuhiro Mikuni

Journal of neurosurgery 1 - 9 2025.01 [International journal]

OBJECTIVE: Awake craniotomy is commonly used to resect lesions located near the language area during brain surgery. However, it is often difficult to perform language tasks due to several limitations such as difficulty in awakening during surgery and intraoperative seizures. This study investigated the clinical significance of bidirectional corticocortical evoked potential (CCEP) monitoring as a new approach to evaluate intraoperative language function. METHODS: This study enrolled 12 patients who underwent awake brain tumor resection with intraoperative CCEP monitoring to assess language function. Electrodes were placed on the frontal and temporoparietal lobes based on the location of the arcuate fasciculus identified with preoperative diffusion tensor imaging to measure CCEPs intraoperatively in two directions: from the frontal lobe to the temporoparietal lobe of the language-dominant side, and vice versa. Correlations between CCEP amplitudes or latencies before and after tumor removal in each direction and postoperative language function assessed with the Western Aphasia Battery were analyzed. RESULTS: Nine of the 12 patients showed language-related CCEP responses in both directions before, during, and after tumor removal. One patient who showed decreased CCEP amplitudes in both directions after tumor removal exhibited aphasia for as long as 1 month postoperatively. In contrast, of the 6 patients whose CCEP amplitude in only a single direction was reduced or disappeared, 4 had no deterioration of language function and the other 2 had temporary deterioration of language function during the 1st postoperative week, which improved by 1 month postoperatively. CONCLUSIONS: This study indicated that bidirectional CCEP measurement may increase the precision of intraoperative language function monitoring.

DOI PubMed

Functional Brain Mapping Using Depth Electrodes

Chie Kamada, Rei Enatsu, Seiichiro Imataka, Aya Kanno, Satoko Ochi, Nobuhiro Mikuni

World Neurosurgery ( Elsevier BV ) 188 e288 - e296 2024.08

DOI

An anatomo-functional study of the interactivity between the paracentral lobule and the primary motor cortex.

Yusuke Kimura, Shoto Yamada, Katsuya Komatsu, Rei Enatsu, Ryota Sato, Chie Kamada, Ayaka Sasagawa, Tsukasa Hirano, Masayasu Arihara, Nobuhiro Mikuni

Journal of neurosurgery 1 - 9 2024.05 [International journal]

OBJECTIVE: The purpose of this study was to understand the anatomical and functional connections between the paracentral lobule (PCL) and the primary motor cortex (M1) of the human brain. METHODS: This retrospective study included 16 patients who underwent resection of lesions located near M1. Nine patients had lesions in the dominant hemisphere. Tractography was performed to visualize the connectivity between two regions of interest (ROIs)-the convexity and the interhemispheric fissure-that were shown by functional MRI to be activated during a finger tapping task. The number, mean length, and fractional anisotropy (FA) of the fibers between the ROIs were estimated. During surgery, subdural electrodes were placed on the brain surface, including the ROIs, using a navigation system. Cortico-cortical evoked potentials (CCEPs) were evoked by applying electrical stimuli to the hand region of M1 using electrodes placed on the convexity and were measured with electrodes placed on the interhemispheric fissure. To verify CCEP bidirectionality, electrical stimuli were applied to electrodes on the interhemispheric fissure that showed CCEP responses. Correlations of CCEP amplitudes and latencies with the number, mean length, and mean FA value obtained from tractography were determined. The correlations between these parameters and perioperative motor functions were also analyzed. RESULTS: Fibers of 14 patients were visualized by diffusion tensor imaging (DTI). Unidirectional CCEPs between the PCL and M1 were measurable in all 16 patients, and bidirectional CCEPs between them were measurable in 14 patients. There was no significant difference between the two directions in the maximum CCEP amplitude or latency (amplitude, p = 0.391; latency, p = 0.583). Neither the amplitude nor latency showed any apparent correlation with the number, mean length, or mean FA value of the fibers obtained from tractography. Pre- and postoperative motor function of the hands was not significantly correlated with CCEP amplitude or latency. The number and mean FA value of fibers obtained by DTI, as well as the maximum CCEP amplitude, varied between patients. CONCLUSIONS: This study demonstrated an anatomical connection and a bidirectional functional connection between the PCL, including the supplementary motor area, and M1 of the human brain. The observed variability between patients suggests possible motor function plasticity. These findings may serve as a foundation for further studies.

DOI PubMed

【臨床てんかん学における最新の話題】最新のてんかん外科治療

江夏怜

40 36 - 45 2023.12 [Refereed] [Invited]

【大脳白質解剖と脳内ネットワーク2024 脳機能と脳科学がみえる】大脳白質解剖・脳内ネットワークのTips 脳内ネットワーク解明とその歴史

江夏怜

脳神経外科速報 33 ( 6 ) 770 - 771 2023.11 [Invited]

Intraoperative nerve stimulation during vagal nerve stimulator placement

Chie Kamada, Rei Enatsu, Aya Kanno, Satoko Ochi, Shoto Yamada, Ryota Sato, Ryohei Chiba, Nobuhiro Mikuni

Surgical Neurology International ( Scientific Scholar ) 14 312 - 312 2023.09

Background: Vagal nerve stimulation (VNS) is a palliative treatment for refractory epilepsy and intraoperative nerve stimulation is applied to the vagal and other nerves to prevent electrode misplacement. We evaluated these thresholds to establish intraoperative monitoring procedures for VNS surgery. Methods: Forty-six patients who underwent intraoperative nerve stimulation during VNS placement were enrolled. The vagal nerve and other exposed nerves were electrically stimulated during surgery, and muscle contraction was confirmed by electromyography of the vocal cords and visual recognition of cervical muscle contraction. The nerve thresholds and the most sensitive parts of the vagal nerve were analyzed retrospectively. Results: The stimulation of vagal nerves induced vocal cord responses in all 46 patients; the median thresholds of the most sensitive parts and all parts were 0.2 mA (range: 0.05–0.75 mA) and 0.25 mA (range: 0.15–1.5 mA), respectively. The medial middle region was identified as the most sensitive part of the vagal nerve in the majority of participants (82.5%). In 11 patients, other cervical nerves were stimulated and sternohyoid muscle contraction was induced with a median threshold of 0.35 mA (range: 0.1–0.7 mA) in eight patients, while sternocleidomastoid muscle contraction was induced with a median threshold of 0.2 mA (range: 0.1–0.2 mA) in three. Conclusion: Intraoperative stimulation of vagal nerves induces vocal cord responses with locational variations, and the middle part stimulation could minimize the stimulus intensities. The nerves innervating the sternohyoid and sternocleidomastoid muscles may be exposed during the procedure. Knowledge of these characteristics will enhance the effectiveness of this technique in future applications.

DOI

脳神経外科硬膜下電極と定位的頭蓋内脳波(SEEG)の使い分けは?【深部や両側てんかん原性領域の検索にはSEEG,機能マッピングが必要であれば硬膜下電極を第一に考える】

菊池隆幸, 江夏怜

日本医事新報 ( 5186 ) 52 - 52 2023.09 [Invited]

How do you teach/master Neurosurgicalテクニック?脳波編(第15回)(最終回) 切除計画を立てる!!

江夏怜

脳神経外科速報 33 ( 5 ) 668 - 674 2023.09

脳神経外科不随意運動に対する外科治療の適応と最近の動向は?【薬剤抵抗性の場合にDBS,凝固術,MRgFUSなどが適応となる】

江夏怜, 安部洋

日本医事新報 5183 55 - 55 2023.08

How do you teach/master Neurosurgicalテクニック?脳波編(第14回) 皮質刺激による脳機能マッピング

江夏怜

脳神経外科速報 ( (株)メディカ出版 ) 33 ( 4 ) 540 - 550 2023.07

Computational Fluid Dynamics Analysis Features in Aneurysm Development in Rats.

Shoichi Komura, Katsuya Komatsu, Takeshi Mikami, Yukinori Akiyama, Sangnyon Kim, Rei Enatsu, Hiroshi Nagahama, Nobuhiro Mikuni

Neurologia medico-chirurgica 63 ( 6 ) 250 - 257 2023.06 [Domestic journal]

The investigation of how to control the development and growth of cerebral aneurysms is important for the prevention of subarachnoid hemorrhage. Although there have been several types of research studies on computational fluid dynamics (CFD) analysis of brain aneurysm development and growth, there has been no unified interpretation of the CFD analysis results. The purpose of this study is to clarify the characteristics of CFD analysis results related to the development of cerebral aneurysms using an animal model. Nineteen rat models of cerebral aneurysms were created, and the CFD analysis results between the cerebral aneurysm group [n = 10; the aneurysm was observed on magnetic resonance angiography (MRA) within 10 weeks after aneurysm induction surgery] and the nonaneurysm group (n = 9) were compared. All aneurysms were confirmed on the proximal segment of the left cerebral artery (P1), and the cross-sectional area and curvature of the left P1 were evaluated together. In the cerebral aneurysm group, there was a decrease in wall shear stress (WSS) that is consistent with the location of the aneurysm compared to the nonaneurysm group. The cross-sectional area of the left P1 gradually increased in the aneurysm group but not in the nonaneurysm group. The mean curvature in the entire left P1 was higher in the aneurysm group than in the nonaneurysm group. This study revealed that the development of cerebral aneurysms is due to changes in vascular morphology, namely, an increase in vessel diameter and a high curvature, and a decreased WSS consistent with the site of aneurysm development using this animal model.

DOI PubMed

Microbleeds Due to Reperfusion Enhance Early Seizures after Carotid Ligation in a Rat Ischemic Model.

Takuro Saito, Takeshi Mikami, Tsukasa Hirano, Hiroshi Nagahama, Rei Enatsu, Katsuya Komatsu, Satoshi Okawa, Yukinori Akiyama, Nobuhiro Mikuni

Neurologia medico-chirurgica 63 ( 6 ) 228 - 235 2023.06 [Domestic journal]

Impaired reperfusion in ischemic brain disease is a condition that we are increasingly confronted with owing to recent advances in reperfusion therapy. In the present study, rat models of reperfusion were investigated to determine the causes of acute seizures using magnetic resonance imaging (MRI) and histopathological specimens. Rat models of bilateral common carotid artery ligation followed by reperfusion and complete occlusion were created. We compared the incidence of seizures, mortality within 24 h, MRI, and magnetic resonance spectroscopy (MRS) to evaluate ischemic or hemorrhagic changes and metabolites in the brain parenchyma. In addition, the histopathological specimens were compared with those observed on MRI. In multivariate analysis, the predictive factors of mortality were seizure (odds ratios (OR), 106.572), reperfusion or occlusion (OR, 0.056), and the apparent diffusion coefficient value of the striatum (OR, 0.396). The predictive factors of a convulsive seizure were reperfusion or occlusion (OR, 0.007) and the number of round-shaped hyposignals (RHS) on susceptibility-weighted imaging (SWI) (OR, 2.072). The incidence of convulsive seizures was significantly correlated with the number of RHS in the reperfusion model. RHS on SWI was confirmed pathologically as microbleeds in the extravasation of the brain parenchyma and was distributed around the hippocampus and cingulum bundle. MRS analysis showed that the N-acetyl aspartate level was significantly lower in the reperfusion group than in the occlusion group. In the reperfusion model, RHS on SWI was a risk factor for convulsive seizures. The location of the RHS also influenced the incidence of convulsive seizures.

DOI PubMed

Transcranial electrical stimulation technique for induction of unilateral motor evoked potentials.

Shoto Yamada, Rei Enatsu, Shu Ishikawa, Yusuke Kimura, Katsuya Komatsu, Tomohiro Chaki, Yukinori Akiyama, Takeshi Mikami, Nobuhiro Mikuni

Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology 150 194 - 196 2023.06 [International journal]

OBJECTIVE: Transcranial electrical stimulation motor evoked potentials (TES-MEP) are widely used to monitor motor function; however, broad current spread and induced body movement are limitations of this technique. We herein report a localized stimulation technique for TES-MEP that induces unilateral MEP responses. METHODS: The stimulation of C1(+)-C4(-) or C2(+)-C3(-) was performed to induce right- or left-sided muscle contraction, respectively, in 70 patients. Electromyography was recorded by placing electrodes on the bilateral abductor pollicis brevis (APB) and abductor hallucis (AH) muscles. Stimulation conditions were regulated in the range to induce unilateral muscle contractions contralateral to the anodal stimulation. The thresholds and amplitudes of TES-MEP were retrospectively analyzed. RESULTS: The thresholds of APB were lower than those of AH in 47 patients, AH thresholds were lower than those of APB in 6 patients, and both APB and AH started to respond at the same intensity in 15 patients. This technical stimulation induced contralateral limb contractions with a suprathreshold stimulation of 129.4 ± 35.6 mA (mean ± standard deviation) in 68 patients (97%). Amplitudes in the suprathreshold stimulation of APB and AH responses were 727.5 ± 695.7 and 403.3 ± 325.7 μV, respectively. CONCLUSIONS: The C1(+)-C4/C2(+)-C3(-) stimulation in TES-MEP enables a localized stimulation to induce unilateral MEP responses. SIGNIFICANCE: Our stimulation technique enables the stable and safe monitoring of unilateral limbs, and contributes to the reliable monitoring of motor function in neurosurgery.

DOI PubMed

Steady-State Cortico-Cortical Evoked Potential.

Masayasu Arihara, Rei Enatsu, Satoko Ochi, Ayaka Sasagawa, Tsukasa Hirano, Tomoyoshi Kuribara, Shoto Yamada, Yusuke Kimura, Masao Matsuhashi, Nobuhiro Mikuni

Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society 40 ( 4 ) 301 - 309 2023.05 [International journal]

PURPOSE: The present study evaluated the utility of the steady-state responses of cortico-cortical evoked potentials (SSCCEPs) and compared them with the responses of conventional CCEPs. METHODS: Eleven patients with medically intractable focal epilepsy who underwent the implantation of subdural electrodes or stereoelectroencephalography were enrolled. Conventional CCEPs were obtained by averaging responses to alternating 1-Hz electrical stimuli, and 5-Hz stimuli were delivered for recording SSCCEPs. The distribution of SSCCEPs was assessed by a frequency analysis of fast Fourier transform and compared with conventional CCEPs. RESULTS: Steady-state responses of cortico-cortical evoked potentials were successfully recorded in areas consistent with conventional CCEPs in all patients. However, SSCCEPs were more easily disturbed by the 5-Hz stimulation, and small responses had difficulty generating SSCCEPs. CONCLUSIONS: Steady-state responses of cortico-cortical evoked potentials may be a useful alternative to conventional CCEPs.

DOI PubMed

パーキンソン病患者の視床下核β oscillationと神経症状の相関

北川まゆみ, 江夏怜

臨床神経学 ( (一社)日本神経学会 ) 63 ( 5 ) 329 - 329 2023.05

How do you teach/master Neurosurgicalテクニック?脳波編(第13回) 頭蓋内脳波の判読

江夏怜

脳神経外科速報 ( (株)メディカ出版 ) 33 ( 3 ) 376 - 386 2023.05

Visual networks: Electric brain stimulation and diffusion tensor imaging.

Tomoaki Tamada, Rei Enatsu, Takuro Saito, Ryohei Chiba, Aya Kanno, Nobuhiro Mikuni

Revue neurologique 2023.04 [International journal]

OBJECTIVE: The present study investigated the networks of visual functional areas using electric brain stimulation (EBS) and diffusion tensor imaging (DTI). METHODS: Thirteen patients with intractable focal epilepsy in which visual functional areas were identified by EBS were enrolled. An electric stimulation at 50Hz was applied to electrodes during several tasks. DTI was used to identify subcortical fibers originating from the visual functional areas identified by EBS. RESULT: The electrical stimulation induced three types of visual symptoms: visual illusions (change of vision), visual hallucinations (appearance of a new object), and blurred vision. Visual illusions were associated with stimulation of lateral temporo-parieto-occipital areas, and visual hallucinations with stimulation of lateral/basal temporal areas, the occipital lobe and the precuneus. Stimulus intensities eliciting visual illusions were significantly higher than those for visual hallucinations. Tractography revealed that the superior fronto-occipital fasciculus was associated with visual illusions and the middle longitudinal fasciculus with visual hallucinations, and both symptoms shared several subcortical fibers such as the vertical occipital fasciculus, inferior fronto-occipital fasciculus, superior longitudinal fasciculus, inferior longitudinal fasciculus, optic radiations, and commissural fibers. CONCLUSION: The present study revealed the characteristic cortical regions and networks of visual functional areas. The results obtained provide information on human visual functions and are a practical guide for electrical cortical stimulation.

DOI PubMed

How do you teach/master Neurosurgicalテクニック?脳波編第12回頭蓋内電極留置の実際

江夏怜

脳神経外科速報 ( (株)メディカ出版 ) 33 ( 2 ) 256 - 265 2023.03

Usefulness of Intraoperative Electrocorticography for the Localization of Epileptogenic Zones.

Ryohei Chiba, Rei Enatsu, Aya Kanno, Tomoaki Tamada, Takuro Saito, Ryota Sato, Nobuhiro Mikuni

Neurologia medico-chirurgica 63 ( 2 ) 65 - 72 2023.02 [Domestic journal]

Intraoperative electrocorticography (iECoG) is widely performed to identify irritative zones in the cortex during brain surgery; however, several limitations (e.g., short recording times and the effects of general anesthesia) reduce its effectiveness. The present study aimed to evaluate the utility of iECoG for localizing epileptogenic zones. We compared the results of iECoG and chronic electrocorticography (cECoG) in 25 patients with refractory epilepsy. Subdural electrodes were implanted with iECoG under general anesthesia (2% sevoflurane). cECoG recordings were performed for 3-14 days. The distribution of iECoG spikes was compared with cECoG spike, seizure onset zone, and resection areas. The concordance patterns of each distribution were classified into four patterns: Group 1: No spike in iECoG, Group 2: concordant (2a: iECoG smaller, 2b: iECoG larger, Group 3: discordant >50%). The concordance rate of interictal spikes, seizure onset zones, and resection areas were 88.0% (Group 2a: 72.0%, Group 2b: 16.0%), 70.0% (Group 2a: 25.0%, Group 2b: 45.0%), and 81.0% (Group 2a: 42.9%, Group 2b: 38.1%), respectively. The resection of iECoG spike areas significantly correlated with good surgical outcomes. The indication and limitations of iECoG need to be realized, and the complementary use of iECoG and cECoG may enhance clinical utility.

DOI PubMed

How do you teach/master Neurosurgicalテクニック?脳波編(第11回) 侵襲的モニタリングの術前計画

江夏怜

脳神経外科速報 ( (株)メディカ出版 ) 33 ( 1 ) 142 - 149 2023.01

　 PREV - NEXT 　

<ENATSU Rei>

Papers - ENATSU Rei