Details of a Researcher - Akiyama, Takenori

Papers - Akiyama, Takenori

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蝶形骨小翼部硬膜動静脈瘻の1例

菊地亮吾, 秋山武紀, 中村明義, 宮崎宏道

脳卒中の外科 ((一社)日本脳卒中の外科学会) 50 ( 1 ) 64 - 69 2022.01

ISSN 0914-5508

Carotid body tumor with neck metastasis due to germline SDHB variant: a case report and literature review

Mikoshiba Takuya, Yoshihama Keisuke, Ito Fumihiro, Sekimizu Mariko, Nakamura Shintaro, Nagai Ryoto, Akiyama Takenori, Matsubara Kentaro, Obara Hideaki, Ozawa Hiroyuki

INTERNATIONAL CANCER CONFERENCE JOURNAL 11 ( 1 ) 6 - 11 2022.01

ISSN 2192-3183

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特集頭頸部の再建をマスターする!〔特別付録Web動画〕《部位別再建法》頸動脈の再建

小澤宏之, 秋山武紀, 尾原秀明

耳鼻咽喉科・頭頸部外科 (株式会社医学書院) 93 ( 13 ) 1138 - 1143 2021.12

ISSN 0914-3491

Surgical resection of arteriovenous fistula at the cauda equina

Shimizu T, Nagoshi N, Akiyama T, Suzuki S, Nori S, Tsuji O, Okada E, Yagi M, Watanabe K, Nakamura M, Matsumoto M

Spinal Cord Series and Cases (Spinal Cord Series and Cases) 7 ( 1 ) 29 2021.12

Joint Work, ISSN 2058-6124

Introduction: Although spinal arteriovenous fistula (AVF) has been reported widely, AVF at the cauda equina is quite rare. We described a case of AVF at the cauda equina that was fed by the distal radicular artery (DRA). Case presentation: A 50-year-old woman presented with sudden weakness of the lower extremities. Magnetic resonance imaging (MRI) revealed a lesion with a highly intense signal at the conus medullaris, which was surrounded by several low-intensity signals (flow voids). Digital subtraction angiography revealed AVF at the cauda equina and that it was fed by the DRA, which was directly fed by the L3 segmental artery. We performed surgical resection of the AVF while monitoring motor-evoked potentials. The patient’s postoperative course was uneventful, and her neurological symptoms gradually resolved. MRI 2 years after surgery showed the disappearance of both intramedullary edema and the flow voids. Discussion: For the AVF, located at the cauda equina and fed by the DRA in this case, surgical resection or endovascular embolization could have been selected. We performed open surgery to achieve complete obliteration of the AVF, which led to postoperative functional recovery without any adverse events. However, only a limited number of AVFs at the level of the cauda equina have been reported, and treatment standards have not been established. Further studies of AVFs at the cauda equina are necessary to clarify the epidemiological characteristics and clinical outcomes with an appropriate sample size.

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[Mechanisms Underlying Novel Complications Associated with Neuroendovascular Therapy for Cerebrovascular Diseases].

Akiyama T

Brain and nerve = Shinkei kenkyu no shinpo (株式会社医学書院) 73 ( 9 ) 1007 - 1012 2021.09

Single Work, ISSN 1881-6096

Angio-anatomical study of the pterygovaginal artery based on cone-beam computed tomography

Yoshida K, Akiyama T, Raz E, Kamamoto D, Ozawa H, Toda M

Neuroradiology (Neuroradiology) 63 ( 8 ) 1325 - 1333 2021.08

Joint Work, ISSN 00283940

Purpose: To investigate the anatomical characteristics and clinical implications of the pterygovaginal artery (PtVA), a recurrent branch from the distal internal maxillary artery (IMA), which courses through the pterygovaginal canal that connects the pterygopalatine fossa and nasopharynx. Methods: Eighty-two patients with 90 sides of cone-beam computed tomography (CBCT) reconstructed from rotational angiography of the external or common carotid artery with a field of view covering the pterygopalatine fossa were retrospectively reviewed. The origin from the IMA, branching type, distribution, and anastomoses was evaluated. The underlying lesions were 36 hypervascular lesions with possible supply from PtVA (17 cavernous sinus arteriovenous fistulas (AVFs), 6 anterior condylar AVFs, and 13 nasopharyngeal, parasellar, or paraclival tumors) and 46 other diseases. Results: PtVA was identified in 75 sides (83%). It originated from the pterygopalatine segment of the IMA in 45 sides (60%) and from the pterygoid segment in 30 sides (40%). It arose independently (77%), sharing the common trunk with the Vidian artery (15%) or with other branches. It ran posteromedially through the pterygovaginal canal to supply the mucosa over the nasopharyngeal roof, the choanae, and the pharyngeal ostium of the eustachian tube. It anastomosed with the ascending pharyngeal artery (n=37), the accessory meningeal artery (n=7), and the mandibular artery from the petrous internal carotid artery (n=2). It served as a feeder of osseous AVFs and skull base tumors. Conclusion: PtVA was often identified by CBCT even in normal anatomy. Its detailed angio-anatomy could be evaluated in the presence of parasellar or paraclival hypervascular lesions.

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Molecular investigation of brain tumors progressing during pregnancy or postpartum period: the association between tumor type, their receptors, and the timing of presentation

Ichimura S, Ohara K, Kono M, Mizutani K, Kitamura Y, Saga I, Kanai R, Akiyama T, Toda M, Kohno M, Yoshida K, Sasaki H

Clinical Neurology and Neurosurgery (Clinical Neurology and Neurosurgery) 207 106720 2021.08

Joint Work, ISSN 03038467

Objective: Brain tumors often become clinically evident during pregnancy; however, the mechanism has not been well elucidated. Purpose of this study is to investigate the influence of molecular genetic factors on the progression of brain tumors during pregnancy or the postpartum period. Methods: Twelve cases of brain tumors that presented during pregnancy or postpartum period were included: five gliomas, three meningiomas, two vestibular schwannomas, and two chordomas. Tumor samples were investigated by metaphase comparative genomic hybridization and immunohistochemistry, for chromosomal copy number aberration (CNA) and receptor expression of sex hormones and growth factors. Results: The results were correlated with the timing of tumor presentation in relation to the stage of pregnancy. EGFR, VEGFR-1/2, AR, and c-Myc were expressed in gliomas, PgR, ER, HER-2, VEGFR-1, EGF and VEGFR2 in meningiomas, VEGFR-1 in vestibular schwannomas, and EGFR, VEGFR-1/2, and c-Myc in chordomas. The CNAs of the tumors varied. Four of the five gliomas presented in the 2nd trimester, all three meningiomas in the 3rd trimester or postpartum period, and both of the two schwannomas in the late 2nd trimester. Expression of VEGFR-1/2 and EGFR was observed regardless of the timing of tumor presentation, whereas female hormone receptors and HER-2 were exclusively found in meningiomas. Interestingly, one anaplastic astrocytoma (IDH mut, non-codeleted) that progressed from precedent grade 2 tumor harbored amplification of the MYC locus. Conclusion: Progression of brain tumors during pregnancy is associated with various growth factors as well as sex hormones. The timing of presentation is likely dependent on molecular receptors specific to each tumor type.

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Cone-Beam Computed Tomography Fusion Technique for Vascular Assessment of Skull Base Meningiomas

Yoshida K, Akiyama T, Takahashi S, Miwa T, Horiguchi T, Sasaki H, Toda M

World Neurosurgery (World Neurosurgery) 151 61 - 69 2021.07

Joint Work, ISSN 18788750

Objective: Cone-beam computed tomography (CBCT) images for skull base tumors provide detailed vascular information and localization in regard to surrounding bony structures. We report use of the CBCT fusion technique for skull base meningiomas. Methods: Six patients with petroclival or petrotentorial meningiomas supplied by multiple arterial systems were preoperatively evaluated using CBCT fusion imaging. Fusion images were reconstructed from three-dimensional rotational angiography with contrast agent injections from the internal carotid artery (ICA) and external carotid artery in 4 cases, vertebral artery and external carotid artery in 1 case, and ICA and vertebral artery in 1 case. Results: The feeding pedicles and tumor stains from 2 arterial systems were differentiated by separate colors. The courses and territories of the ICA dural feeders or ICA/vertebral artery pial feeders were easily distinguished from the external carotid artery dural feeders. Anastomoses between thin feeders from different arterial systems could be detected. Mixed stain (stain with both colors) was observed in some tumor compartments, suggesting dual supply from 2 arterial systems and the presence of peritumoral anastomoses. All patients underwent preoperative embolization without complications. Conclusions: CBCT fusion images clearly visualized the feeders from each arterial system, the vascular compartments within the tumor, and possible peritumoral anastomoses. This technique provides a substantial contribution to both preoperative embolization and surgical resection of skull base meningiomas.

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当院における頸部頸動脈瘤に対する治療戦略

堀口崇, 淺田英穂, 寺尾聡, 秋山武紀, 大石裕美子, 吉田一成

脳卒中の外科 ((一社)日本脳卒中の外科学会) 49 ( 4 ) 259 - 264 2021.07

ISSN 0914-5508

当院で頸部頸動脈瘤に対し直達術を行った6例(男性1例、女性5例、平均年齢56.7歳)について検討した。その結果、全例が症候性内頸動脈瘤であり、瘤径は平均35.8mm、動脈瘤内血栓化を2例に認められた。手術法は3例で動脈瘤の切除と内頸動脈の端々吻合による血行再建が行われ、残る3例で母血管閉塞が行われていた。動脈瘤を切除した3例の病理所見はいずれも動脈硬化性動脈瘤であった。5例が転帰良好であったが、1例は内頸動脈閉塞から中大脳動脈塞栓を生じ、広範な脳梗塞により死亡していた。

Resection of a large cavernous hemangioma following preoperative embolization in a child’s Temporal Bone

Torii Y, Hosoya M, Hasebe N, Ogawa S, Akiyama T, Oishi N, Ogawa K

Journal of International Advanced Otology (Journal of International Advanced Otology) 17 ( 3 ) 269 - 274 2021.05

Research paper (scientific journal), Joint Work, ISSN 13087649

Primary intraosseous cavernous hemangiomas (PICHs) in the temporal bone are very rare. Most treated cases are in adult patients, and there are very few reports involving children. To our knowledge, no cases reported have ever actually adopted embolization in children, although several reports recommend preoperative embolization of the feeding arteries. Here, we present a case of a child with a large cavernous hemangioma developing in the temporal bone. The patient was an 11-year-old girl whose chief complaints were hearing loss, aural fullness, and otalgia. Based on imaging, a lymphoma was initially suspected, but extensive arterial bleeding occurred during biopsy under local anesthesia. Angiography was performed to evaluate the blood flow in the tumor, and revealed the middle meningeal artery as a main feeding artery to the tumor. A huge PICH at the temporal bone was successfully resected following preoperative embolization of the feeding artery.

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Comparisons of Characteristics and Outcomes after Mechanical Thrombectomy for Vertebrobasilar Occlusion with Cardioembolism or Atherosclerotic Brain Infarction: Data from the Tokyo-Tama-Registry of Acute Endovascular Thrombectomy (TREAT)

Katsumata M, Ota T, Tsuruta W, Akiyama T, Sakai Y, Shigeta K, Kaneko J, Nogawa S, Ichijo M, Shiokawa Y, Hirano T

World Neurosurgery (World Neurosurgery) 148 e680 - e688 2021.04

Research paper (scientific journal), Joint Work, ISSN 18788750

Background: Some reports suggest the efficacy of mechanical thrombectomy (MT) for acute vertebrobasilar artery (VBA) occlusion. The major causes of VBA occlusion include cardioembolism (CE) and large-artery atherosclerosis (LAA). However, the clinical characteristics of each cause remain unclear, and they might be important for decision making related to the indications and strategy of MT. Objective: This study aimed to compare functional outcomes and factors affecting outcomes between patients with CE and LAA with acute VBA occlusion. Methods: This was a retrospective and prospective observational study using data from TREAT (Tokyo-Tama-Registry of Acute Endovascular Thrombectomy), a multicenter registry of MT for acute large-vessel occlusion in the Tokyo metropolitan area. Patients with VBA occlusion classified into CE and LAA groups were analyzed. The primary outcome was a modified Rankin Scale score of 0–2 at 90 days. Results: Seventy-nine patients (57 with CE and 22 with LAA) were eligible from January 2015 to March 2020. Despite significantly shorter puncture-to-recanalization and onset-or-last-well-known-to-recanalization times in the CE group, the primary outcome was not significantly different between the 2 groups (CE, 31.6% vs. LAA, 45.5%; P = 0.248). In the subgroup analysis, patients with CE had worse clinical outcomes in the onset-or-last-well-known-to-door time ≥180 minutes, onset-or-last-well-known-to-door time ≥300 minutes, and low posterior circulation Alberta Stroke Program Early CT Score (≤7) subgroups. Conclusions: Functional outcomes of VBA occlusion were not significantly different between CE and LAA. Based on the subgroup analysis, patients with CE might have poorer collateral status than do patients with LAA, and earlier recanalization might therefore be desired.

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Angioarchitecture and Pre-Surgical Embolization of Central Nervous System Solitary Fibrous Tumor/Hemangiopericytoma

Akiyama Takenori, Takahashi Satoshi, Nagoshi Narihito, Ozawa Hiroyuki, Sasaki Hikaru, Toda Masahiro

脳神経血管内治療 (特定非営利活動法人日本脳神経血管内治療学会) 15 ( 5 ) 316 - 322 2021

Joint Work, ISSN 1882-4072

Objective: Hemangiopericytomas (HPCs) and solitary fibrous tumors (SFTs) have been categorized as the same disease entity, SFT/HPC, since 2016. SFT/HPC is one of the most highly vascularized brain tumors, distinct from meningioma. The angioarchitecture also differs between these tumors. Understanding these differences can help interventionalists perform presurgical embolization more safely and effectively.Methods: Vascular structures were analyzed in eight patients with central nervous system (CNS) SFT/HPCs, all of whom received presurgical embolization. The type of embolic materials used and the complication rates were compared between the CNS SFT/HPC cases and 39 meningioma cases treated within the same period. Characteristic angiographic features of SFT/HPC were identified, and we present their interpretation and utilization to inform embolization strategies.Results: Four angiographic features of SFT/HPCs were identified. 1) Persistence of tumor stain and 2) feeders from branches of the internal carotid artery or vertebral artery were observed in all cases, while 3) connecting feeders (highly dilated vessels that originate from branches of other feeder vessels and run along the surface of one tumor compartment to feed another compartment) were observed in five out of eight cases. 4) Finally, an intratumoral arteriovenous shunt was identified in one case. The frequency of liquid embolic material use was significantly higher in SFT/HPC cases than in meningioma cases. No complications were observed in SFT/HPC cases, and all tumors were effectively removed.Conclusion: The most appropriate presurgical embolization strategies differ between SFT/HPCs and meningiomas depending on the tumor angioarchitecture. A thorough understanding of the vascular anatomy is necessary for safe and effective embolization of SFT/HPCs.

Pterygovaginal artery as a target of embolization before endoscopic skull base surgery

Yoshida K, Akiyama T, Raz E, Kamamoto D, Ozawa H, Toda M

Neuroradiology Journal (Neuroradiology Journal) 34 ( 6 ) 19714009211013490 - 682 2021

Joint Work, ISSN 19714009

Background: The pterygovaginal artery (PtVA), a recurrent branch of the internal maxillary artery (IMA), can be a feeder of skull base tumors. Preoperative embolization can help endoscopic resection of hypervascular lesions, which is performed under a narrow surgical space with restricted instrumental maneuverability. Methods: We performed preoperative embolization in five cases with hypervascular skull base lesions supplied by the PtVA, four of which were resected via endoscopic endonasal approach. In two cases, selective PtVA embolization through the distal IMA was successfully conducted. Results: In all the cases, intraoperative bleeding during endoscopic resection was easily controlled. The medial and lateral origins of the PtVA from the IMA were demonstrated by cone-beam CT images reconstructed from three-dimensional rotational angiography, and anastomoses around the eustachian tube and soft palate were visualized by superselective angiography. Conclusions: The PtVA embolization can be an effective strategy before endoscopic skull base tumor resection. When embolizing through the PtVA, clinicians should be aware of its anatomical variations and dangerous anastomoses. Understanding the surrounding angioarchitecture by angiographic techniques helps ensure safe embolization.

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Stepwise improvement in limb shaking achieved by staged angioplasty for severe carotid stenosis

Takahara K, Akiyama T, Yoshida K, Yamada H, Oishi Y, Kuranari Y, Katsumata M, Toda M

Neuroradiology Journal (Neuroradiology Journal) 35 ( 2 ) 19714009211036690 - 263 2021

Joint Work, ISSN 19714009

Cerebral hyperperfusion syndrome is a rare but severe complication of carotid artery stenting or carotid endarterectomy. Staged angioplasty is reportedly an effective strategy to avoid cerebral hyperperfusion syndrome. We encountered a case of internal carotid artery stenosis with a rare clinical presentation of limb shaking that was successfully improved by staged angioplasty. To our knowledge, there are no reported cases of limb shaking treated with staged angioplasty. A 76-year-old woman presented with continuous chorea in her left lower limb and shoulder. Medical examination revealed a tiny cerebral infarction in the right corona radiata and severe right internal carotid artery stenosis. Angiography showed near occlusion of the right internal carotid artery. Staged angioplasty was performed to avoid the risk of cerebral hyperperfusion syndrome. The first angioplasty resulted in an expanded diameter of 2.5 mm and was followed by definitive carotid artery stenting using a closed-cell stent 3.5 weeks later. Limb shaking improved in a stepwise manner along with an improvement in internal carotid artery stenosis and distal flow state with no signs of cerebral hyperperfusion syndrome. Patients with internal carotid artery stenosis or occlusion presenting with limb shaking have been suggested to have impaired cerebrovascular reactivity, which is also thought to be a risk factor for cerebral hyperperfusion syndrome. The stepwise improvement in limb shaking observed in this case supports the idea that the pathophysiology of limb shaking is related to cerebral haemodynamic impairment. Measures to prevent cerebral hyperperfusion syndrome, including staged angioplasty, should be actively considered in patients with limb shaking because the symptoms themselves suggest severe hypoperfusion.

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Current Treatments for Cervical Carotid Artery Aneurysms

HORIGUCHI Takashi, ASADA Hideo, TERAO Satoshi, AKIYAMA Takenori, OISHI Yumiko, YOSHIDA Kazunari

Surgery for Cerebral Stroke (The Japanese Society on Surgery for Cerebral Stroke) 49 ( 4 ) 259 - 264 2021

ISSN 0914-5508

We report the clinical features of six patients who underwent direct surgery at our hospital for large or giant cervical internal carotid artery aneurysms (CICAAs). Three patients underwent aneurysm resection with end-to-end anastomosis of the internal carotid artery (ICA), and three patients underwent proximal occlusion of the ICA. Five patients had good outcomes, including one case with transient dysphagia. In one case, a middle cerebral artery embolization occurred due to ICA occlusion, and the patient died due to extensive cerebral infarction. To avoid ischemic complications in direct surgery for CICAA, preoperative cerebral blood flow assessment and perioperative antithrombotic therapy are indispensable. In addition, to avoid lower cranial nerve palsy during dissection of the aneurysm from surrounding structures, a bloodless surgical field; safe, reliable internal shunt insertion and vascular suture techniques; and an accurate understanding of the anatomy of the neck are also necessary.

Role of Surgery in the Management of Intracranial Dural Arteriovenous Fistula

AKIYAMA Takenori, HORIGUCHI Takashi, TAKAHASHI Satoshi, OHIRA Takayuki, AKIYAMA Takekazu, YOSHIDA Kazunari

Surgery for Cerebral Stroke (The Japanese Society on Surgery for Cerebral Stroke) 48 ( 6 ) 420 - 426 2020.11

Joint Work, ISSN 0914-5508

Summary: Following technological advances in endovascular therapy, this approach is preferred over　surgery as the mainstay of treatment for dural arteriovenous fistula (dAVF). However, surgery remains important, and its role should be re-evaluated. In this retrospective study, we investigated the outcomes of surgical treatment for dAVF, focusing on the pitfalls of this approach in 101 patients who underwent surgery for dAVF. We analyzed the characteristics of lesions treated surgically, as well as treatment outcomes including the morbidity, AV shunt occlusion, and recurrence rates. The results included 20 patients who underwent only surgical treatment. The surgical morbidity rate was 5%. All AV shunts were extirpated at radical procedures; however, recurrence occurred in one patient. In conclusion, surgery serves as definitive treatment for specific types of dAVF. Careful decision-making regarding an endovascular vs. an open surgical approach is important, together with preparedness to manage the associated challenges, as observed in this case series.

Novel method to evaluate the risk of tumor adhesions and post-operative hemorrhage of meningiomas using 320 row CT-DSA: A clinical research study.

Nobuhiko Arai, Katsuhiro Mizutani, Takashi Horiguchi, Takenori Akiyama, Satoshi Takahashi, Kaoru Yanagisawa, Kazunari Koike, Kazunari Yoshida

Acta neurochirurgica (Acta Neurochirurgica) 162 ( 9 ) 2145 - 2153 2020.09

Joint Work, Accepted, ISSN 00016268

OBJECTIVE: Meningioma is an extra-axial tumor that forms adhesions toward the brain surface in the course of its growth. Predicting adhesions between the tumor and the brain surface leads to better predictions of surgical results. There are few studies on brain-tumor adhesions or postoperative hemorrhage. This study aimed to assess tumor vascularity of the dura and cerebral surface, and predict surgical outcomes using four-dimensional computed tomography angiography (4D CTA). PATIENTS AND METHODS: Using a dynamic contrast CT, we conducted a retrospective study of 27 patients with convexity (n = 15), falx (n = 6), and parasagittal (n = 6) meningiomas treated in our hospital from January 2016 to September 2018. We set the region of interest on the dural layer and cerebral surface side of meningiomas and calculated the mean CT value in each region. Distribution of blood flow in the tumor was classified into two groups: A, which has a higher CT value of the dural side than that of the brain surface side at every timing, and B, which meets the criteria other than those in group A. Demographic data, preoperative characteristic images, and postoperative complications were compared between the groups. RESULTS: Twelve and 15 patients were classified into groups A and B, respectively. The extent of adhesions against the cerebral cortex in group A was significantly less severe compared with that in group B (p = 0.038). The rate of postoperative hemorrhage occurrence in group B (53%) was significantly higher than that in group A (8%) (p = 0.04). There were no significant differences in the other preoperative characteristic images or perioperative parameters between groups A and B. CONCLUSION: A 320-row dynamic contrast CT scanner can detect meningiomas with a high probability of severe adhesion toward the brain surface and postoperative intraparenchymal hematoma.

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Descending musculospinal branch of the ascending pharyngeal artery as a feeder of carotid body tumors: Angio-architecture and embryological consideration

Shibao S, Akiyama T, Ozawa H, Tomita T, Ogawa K, Yoshida K

Journal of Neuroradiology (Journal of Neuroradiology) 47 ( 3 ) 187 - 192 2020.05

Joint Work, ISSN 01509861

Introduction: Although the ascending pharyngeal artery (APhA) is known as a main feeder of carotid body tumors (CBTs), its detailed architecture and embryological consideration have not been described. The objective of this study was to describe the architecture of a descending feeder of the APhA and to consider its origin embryologically through a review of our CBT embolizations. Methods: We retrospectively analyzed data from patients with CBTs who underwent transarterial embolization or angiographic examination–only between July 2010 and February 2017. The arterial supply of the tumors, the number of feeder pedicles, the mean tumor size, embolization materials, complication of embolization, and extent of tumor removal were assessed. The embryological origin of feeding artery was considered based on the literature. Results: Eighteen patients with 20 CBTs underwent preoperative embolization or angiographic examination. The number of feeder pedicles was significantly related to the size of the CBT (P = 0.0002). The main feeding artery was the descending branch of APhA, which was hypertrophied and tortuous (18/20, 90%). Embryologically, this artery originated from the musculospinal branch and is termed the “descending musculospinal branch”. Conclusion: The main feeder of the CBTs was the “descending musculospinal branch” of the APhA and needs special consideration such as dangerous anastomosis for embolization.

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Silent MRA: arterial spin labeling magnetic resonant angiography with ultra-short time echo assessing cerebral arteriovenous malformation.

Nobuhiko Arai, Takenori Akiyama, Kazuhiro Fujiwara, Kazunari Koike, Satoshi Takahashi, Takashi Horiguchi, Masahiro Jinzaki, Kazunari Yoshida

Neuroradiology (Neuroradiology) 62 ( 4 ) 455 - 461 2020.04

Joint Work, Accepted, ISSN 00283940

PURPOSE: MR angiography using the silent MR angiography algorithm (silent MRA), which combines arterial spin labeling and an ultrashort time echo, has not been used for the evaluation of cerebral arteriovenous malformations (CAVMs). We aimed to determine the usefulness of silent MRA for the evaluation of CAVMs. METHODS: Twenty-nine CAVMs of 28 consecutive patients diagnosed by 4D CT angiography or digital subtraction angiography, who underwent both time-of-flight (TOF) MRA and silent MRA, were enrolled. Two observers independently assessed the TOF-MRA and silent MRA images of CAVMs. Micro AVM was defined as AVM with a nidus diameter less than 10 mm. The detection rate, visualization of the components, and accuracy of Spetzler-Martin grade were evaluated with statistical software R. RESULTS: For all 29 CAVMs, 23 (79%) lesions were detected for TOF-MRA and all for silent MRA. Of 10 micro AVMs, only 4 (40%) lesions were detectable on TOF-MRA and all (100%) on silent MRA. The visibility of the nidus and drainer was significantly better for silent MRA than TOF-MRA (p < 0.001), while there was no significant difference in the feeder between the two sequences. The accuracy rates of the Spetzler-Martin grade for the TOF and silent MRA were 38% (11/29) and 79.3% (23/29), respectively (p < 0.001). CONCLUSIONS: Silent MRA is useful for evaluating CAVM components and detecting micro AVM.

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Loss of consciousness at ictus and/or poor World Federation of Neurosurgical Societies grade on admission reflects the impact of EBI and predicts poor outcome in patients with SAH

Takahashi S, Akiyama T, Horiguchi T, Miwa T, Takemura R, Yoshida K

Surgical Neurology International (Surgical Neurology International) 11 ( 40 ) 40 - 40 2020.03

Research paper (scientific journal), Joint Work, ISSN 2229-5097

Background: There are many scores and markers that predict poor outcome in patients with subarachnoid hemorrhage (SAH). However, parameters that can predict outcomes in patients with SAH with high specificity and sensitivity, which can be identified in the early postictal state and utilized as a clinical marker of early brain injury (EBI) have not been identified so far. Methods: Thirty-nine patients with SAH due to a saccular intracranial aneurysm rupture were reviewed. We retrospectively analyzed the relationships between patients' baseline characteristics and patients' outcomes to identify parameters that could predict patient outcomes in the early postictal state. Results: In the univariate analysis, older age (>65), loss of consciousness (LOC) at ictus, poor initial World Federation of Neurosurgical Societies (WFNS) grade (3-5), and delayed cerebral ischemia (DCI) were associated with poor outcome (GOS 1-3). Statistical analyses revealed that combined LOC at ictus and/or poor initial WFNS grade (3-5) was a more powerful surrogate marker of outcome (OR 15.2 [95% CI 3.1-75.5]) than either LOC at ictus or the poor initial WFNS grade (3-5) alone. Multivariate logistic regression analyses revealed that older age, combined LOC at ictus and/or poor initial WFNS grade, and DCI were independently associated with poor outcome. Conclusion: Combined LOC at ictus and/or poor initial WFNS grade (3-5) reflects the impact of EBI and was a useful surrogate marker of poor prognosis in SAH patients, independent of patients' age and state of DCI.

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Endoscopic endonasal removal of a pediatric paranasal ossifying fibroma using preoperative embolization

Saito S, Ozawa H, Ikari Y, Nakahara N, Ito F, Sekimizu M, Kameyama K, Akiyama T, Toda M, Ogawa K

Otolaryngology Case Reports (Otolaryngology Case Reports) 14 2020.03

Joint Work

© 2019 Elsevier Inc. Background: Ossifying fibroma arising in the sinonasal tract is rare. Its treatment includes complete resection; however, this can be challenging to perform due to the well-vascularized nature of the fibroma. Some surgical techniques can control intraoperative hemorrhage; however, to date, no reports have assessed the use of preoperative embolization. Methods: We report a case of a child with ossifying fibroma arising from the ethmoid sinus, which was resected by endoscopic surgery using preoperative transarterial embolization. Conclusions: Embolization was effective in decreasing intraoperative hemorrhage. No complications related to the procedure or operation were encountered. Preoperative embolization should be considered for better control of the bleeding that occurs in ossifying fibromas, similar to that in other well-vascularized tumors.

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Effectiveness of staged angioplasty for avoidance of cerebral hyperperfusion syndrome after carotid revascularization

Hayakawa Mikito, Sugiu Kenji, Yoshimura Shinichi, Hishikawa Tomohito, Yamagami Hiroshi, Fukuda-Doi Mayumi, Sakai Nobuyuki, Iihara Koji, Ogasawara Kuniaki, Oishi Hidenori, Ito Yasushi, Matsumaru Yuji, Ichihashi Toshikazu, Suzuki Kensuke, Tanaka Yoshihiro, Hyodo Akio, Hayase Makoto, Miyakoshi Akinori, Toda Hiroki, Enomoto Yukiko, Egashira Yusuke, Yamauchi Keita, Iwama Toru, Haraguchi Koichi, Yoshioka Tsutomu, Sambongi Yoshiki, Okata Takuya, Mizoue Tatsuya, Uchida Kazutaka, Shirakawa Manabu, Yamada

JOURNAL OF NEUROSURGERY 132 ( 1 ) 51 - 61 2020.01

ISSN 0022-3085

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A questionnaire-based survey to evaluate and improve the current HHT medical and social condition in Japan

Arai N, Akiyama T

Surgical Neurology International (Surgical Neurology International) 11 323 2020

Joint Work, ISSN 2229-5097

Background: Hereditary hemorrhagic telangiectasia (HHT) is a genetic systemic vascular disease affecting multiple organs and shows recurrent intractable symptoms. This disease has not been widely recognized in Japan until recently. Both diagnosed HHT patients and potential ones have faced difficulties because of the unfamiliarity with the disease in Japan. To evaluate the effect and degree of such a Japanese situation, a questionnaire-based survey was executed in this study. Methods: This survey was carried out among the members of HHT Japan Association. The organization consisted of 102 members (as of 6/2019), mainly HHT patients and their family members. A questionnaire was used to gather demographic data, the effort to reach the diagnosis, and information regarding current patients' and their families' medical managements. Results: Of the 102 questionnaires distributed, we have got 56 responses. The participants were mostly female (30) with an average age of 55.4 ± 14.8 (mean ± standard deviation [SD]) years. The average age of males was 53.5 ± 16.4. Relatively many HHT patients were born in huge cities such as Tokyo, Osaka, and Fukuoka Prefecture (n = 4 to 8 patients). The duration between the initial symptoms and the definite diagnosis was 8.8 ± 10.9 years. The number of hospitals involved in the final diagnosis was 2.38 ± 1.83. More than 70% of patients now have to visit at least two departments and 24% of HHT patients did not want their family to screen for HHT. Conclusion: HHT medical practice in Japan should be further modified, for example, by establishing HHT centers and educating primary care physicians and HHT patients.

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Targeted embolisation for coexisting conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas with a varix on a shared drainer†

Yoshida K, Niimi Y, Kamamoto D, Fukumura M, Imai R, Nagoshi N, Akiyama T

British Journal of Neurosurgery (British Journal of Neurosurgery) 1 - 6 2020

Research paper (scientific journal), Joint Work, ISSN 02688697

Background: The coexistence of vascular malformations in the conus medullaris and cauda equina has been rarely reported, and the complex angioarchitecture in multiple arteriovenous lesions remains poorly understood. Case description: A 17-year-old woman presented with a sudden-onset, stepwise worsening of weakness and pain in the bilateral legs. Angiography revealed conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas. One of the drainers was shared between the coexisting lesions and harboured a varix. Targeted embolisation of a fistulous point in the conus lesion was performed with precaution to prevent occluding the common drainage route, which led to symptom improvement with angiographical diminishment of the varix. Conclusions: Recognising that communications between drainers can be observed in multiple spinal arteriovenous lesions is important in facilitating a safe embolisation. Cautious assessment of angiogram with fusion images of cone-beam computed tomography and volumetric T2 magnetic resonance imaging can help in establishing the diagnosis and treatment strategy.

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The Anterior Condylar Arteriovenous Fistula from the Viewpoint of the Osseous Venous Anatomy

MIZUTANI Katsuhiro, AKIYAMA Takenori, YOSHIDA Kazunari

No Kekkannai Chiryo (The Japanese Society for Neuroendovascular Therapy) 5 ( 1 ) 56 - 64 2020

ISSN 2423-9119

The anterior condylar arteriovenous fistula (AC-AVF) is a relatively rare AVF that affects the vasculatures adjacent to the hypoglossal canal. We aimed to discuss the etiology and definition of the AC-AVF from the viewpoint of the osseous venous anatomy. Our recent study, which used modern imaging technology (CT digital subtraction venography and cone beam CT reconstructed from 3D rotational angiography), elucidated the intraosseous venous anatomy in this region and the precise fistulous locations of AC-AVFs. Those findings suggest that the AC-AVF is a group of "osseous" AVF that involves the anterior condylar vein and jugular tubercle venous complex (JTVC), and the osseous veins connected to them. The AC-AVF develops in osseous veins adjacent to the hypoglossal canal, and it is one of the most common subtypes of osseous AVFs. The angioarchitectures and etiology of AC-AVFs discussed herein are essential to understand this clinical entity.

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Analysis of Temporobasal Vein with Short Subdural Segment for Anterior Transpetrosal Approach

Tamura R, Toda M, Morimoto Y, Sato M, Akiyama T, Yoshida K

World Neurosurgery (World Neurosurgery) 132 e554 - e562 2019.12

Joint Work, ISSN 18788750

© 2019 Elsevier Inc. Background: The anterior transpetrosal approach (ATPA) is applied to petroclival and brainstem lesions. Although neurosurgeons need to minimize the risk of neurologic complications, brain retraction is necessary for procedures of ATPA. Bridging veins (BVs) limit mobility of the temporal lobe. In the present study, BVs around the petrous bone were analyzed, focusing on the dural entrance and termination points. Methods: The relationship between subdural and meningeal segments of temporobasal veins (TBVs) was analyzed by preoperative computed tomography venography in 102 patients who underwent ATPA. TBVs were classified by the dural entrance and termination points. Results: TBVs mainly entered the transverse sinus and rarely entered transverse-sigmoid sinus (T-S) junction and superior petrosal sinus (SPS). TBVs entered a dural sinus either directly or indirectly through a meningeal vein. The changes in vascular diameter of the lumen, shape, and course were identified between the subdural and meningeal segments. Generally, BVs with long subdural segment do not limit mobility of the temporal lobe. TBVs draining into the T-S junction and SPS tended to be shorter than those draining into the transverse sinus. Furthermore, a few TBVs indirectly entered the dural sinuses through the meningeal vein (early dural entrance). The subdural segment of these TBVs was much shorter. Conclusions: TBVs entering the T-S junction or SPS with short subdural segment may limit the mobility of the temporal lobe. Changes in vascular diameter, shape, and course were detected by computed tomography venography, which was helpful to detect the subdural-meningeal transition.

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A Novel Flow Dynamics Study of the Intracranial Veins Using Whole Brain Four-Dimensional Computed Tomography Angiography.

Katsuhiro Mizutani, Nobuhiko Arai, Masahiro Toda, Takenori Akiyama, Hirokazu Fujiwara, Masahiro Jinzaki, Kazunari Yoshida

World neurosurgery (World Neurosurgery) 131 e176 - e185 2019.11

Joint Work, ISSN 18788750

BACKGROUND: The flow dynamics of the intracranial venous channels are fundamentally important for understanding intracranial physiology and pathophysiology. However, the method clinically applicable to the evaluation of the flow dynamics of the intracranial venous system has not been well described in the reported data. We have developed a new method to evaluate intracranial venous flow direction and velocity using 4-dimensional (4D) computed tomography angiography (CTA). The aim of the present study was to verify the accuracy and validity of 4D-CTA in a clinical setting. METHODS: We retrospectively analyzed 97 veins from 26 patients (16 cases of arteriovenous shunt disease, 9 intracranial tumor cases, and 1 cerebral aneurysm case) who had undergone both 4D-CTA and conventional digital subtraction angiography (DSA). Using 4D-CTA, we analyzed the time-density curve with gamma distribution extrapolation and obtained the direction of the flow and flow velocity of each vein. The direction of the flow in 4D-CTA was also collated with that obtained using conventional DSA to verify the experimental method. RESULTS: The direction of the flow determined by 4D-CTA was consistent with that of conventional DSA in 94.8% of cases. The average venous flow velocity was 64.3 mm/second and 81.8 mm/second, respectively, in the antegrade and retrograde channels affected by arteriovenous shunts. CONCLUSIONS: The present flow analysis using 4D-CTA enabled us to evaluate the direction and velocity of intracranial venous flow. Other than some limitations, the presented method is reliable and its potential for application in clinical settings is promising.

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Evaluation of cerebral arteriovenous malformations (AVMs) and detection of micro-AVMs in HHT with silent MRA; arterial spin labeling magnetic resonant angiography with ultra-short time echo comparing with TOF MRA

Arai N, Akiyama T, Fujiwara H, Jinzaki M, Yoshida K

ANGIOGENESIS 22 ( 4 ) 603 - 604 2019.11

Joint Work, ISSN 0969-6970

[Diagnosis and Treatment of Intracranial Dural Arteriovenous Fistulas in View of Pathophysiology].

Akiyama T

No shinkei geka. Neurological surgery (株式会社医学書院) 47 ( 9 ) 927 - 941 2019.09

Single Work, ISSN 0301-2603

Factors that predicts poor outcome in patients with subarachnoid hemorrhage

Takahashi S, Akiyama T, Horiguchi T, Yoshida K

JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 39 180 - 180 2019.07

Joint Work, ISSN 0271-678X

Altered expression of microRNAs in body fluids in after aneurysmal subarachnoid hemorrhage

Mihara K, Takahasi S, Yanagisawa K, Mizutani K, Akiyama T, Katayama M, Akaji K, Horiguchi T, Suga S, Yoshida K

JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 39 179 - 179 2019.07

Joint Work, ISSN 0271-678X

A Case of Aggressive Recurrent Intracranial Subdural Hematoma Associated with Angiosarcoma Originating from the Skull

Kanazawa T, Miwa T, Akiyama T, Ohara K, Kosugi K, Nishimoto M, Yoshida K

World Neurosurgery (World Neurosurgery) 126 120 - 123 2019.06

Joint Work, ISSN 18788750

© 2019 Elsevier Inc. Background: Angiosarcoma often arises as a cutaneous disease in the scalp and the face; however, subdural hematoma (SDH) associated with angiosarcoma is extremely rare. Case Description: A 72-year-old woman visited our hospital with gait disorder and progressive consciousness disturbance approximately 3 months after a minor head injury. Initially, on reviewing the results of imaging studies, she was diagnosed with traumatic chronic SDH. Despite repeated operations thereafter, including the embolization of the middle meningeal artery, her general condition progressively worsened, and computed tomography of head repeatedly showed the recurrence of SDH. Based on histopathologic and intraoperative findings, she was finally diagnosed with angiosarcoma originating from the skull. She died shortly thereafter because of aggressive recurrent intracranial SDH caused by leptomeningeal dissemination. Conclusions: In addition to cancers metastatic to the skull or dura mater, angiosarcoma should be included in the differential diagnosis for patients with repeated SDH and bone defect. An effective treatment for angiosarcoma with SDH that shows an unfavorable prognosis has not been established; however, an early diagnosis might be useful for a novel treatment.

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Hemodynamic stress distribution identified by SPECT reflects ischemic symptoms of Moyamoya disease patients.

Nobuhiko Arai, Takashi Horiguchi, Satoshi Takahashi, Tadaki Nakahara, Takenori Akiyama, Masahiro Jinzaki, Kazunari Yoshida

Neurosurgical review (Neurosurgical Review) 43 ( 5 ) 1323 - 1329 2019

Joint Work, ISSN 03445607

This study aimed to validate the hypothesis that the ratio of cerebral blood flow (CBF) at rest in the lenticular nucleus (LN) territory to that in the middle cerebral artery (MCA) territory is higher in symptomatic Moyamoya disease (MMD) patients than in asymptomatic MMD patients. This was a retrospective observational study of adult patients with documented MMD who underwent single-photon emission computed tomography (SPECT) and had been examined at the Department of Neurosurgery of Keio University Hospital during a 10-year period (2006-2016). The diagnosis was made on the basis of typical imaging findings. We classified unoperated MMD patients into three groups: class I, no evidence of stenosis or occlusion hemispheres and without symptoms in unilateral MMD patients; class II, hemispheres with stenosis or occlusion but without ischemic symptoms; and class III, hemispheres with evidence of stenosis or occlusion associated with ischemic symptoms. Hemodynamic stress distribution (hdSD) was defined as the ratio of CBF in one LN to the CBF in the peripheral MCA; this was obtained by SPECT at rest. We compared the values of CBF and hdSD among the groups. A total of 173 adult patients were diagnosed with MMD from January 1, 2006, to January 1, 2016. Among them, 85 MMD patients underwent SPECT studies. After excluding inappropriate cases, 144 hemispheres were included in our analysis. hdSD was significantly higher (p < 0.001) in hemispheres with ischemic symptoms (class III, mean hdSD = 1.1; 36 sides) than in those without symptoms (class II, mean hdSD = 1.03; 82 sides). However, CBF at rest in the MCA or LN was not significantly associated with ischemic symptoms. The optimal threshold for hdSD to have ischemic symptoms was 1.040 (area under the curve; 74% sensitivity 91.7% and specificity 54.9%). We used SPECT to investigate cerebral blood from MMD patients and found that high hdSD values were predictive of ischemic symptom development in these patients.

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The Anterior Condylar Arteriovenous Fistula from the Viewpoint of the Osseous Venous Anatomy

Mizutani Katsuhiro, Akiyama Takenori, Yoshida Kazunari

脳神経血管内治療 (特定非営利活動法人日本脳神経血管内治療学会) 13 ( 3 ) 97 - 104 2019

ISSN 1882-4072

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Traumatic Anterior Ethmoidal Artery Pseudoaneurysm with Repeated Epistaxis Treated by Transarterial Embolization: A Case Report

Kuranari Yuki, Akiyama Takenori, Yanagisawa Kaoru, Kamamoto Dai, Mizutani Katsuhiro, Takahashi Satoshi, Saito Shin, Ozawa Hiroyuki, Ogawa Kaoru, Yoshida Kazunari

脳神経血管内治療 (特定非営利活動法人日本脳神経血管内治療学会) 13 ( 2 ) 72 - 76 2019

Joint Work, ISSN 1882-4072

Objective: Pseudoaneurysms of the internal carotid artery (ICA) and sphenopalatine artery (SPA) are recognized as sources of arterial epistaxis following head and face trauma. However, epistaxis involving pseudoaneurysm of the anterior ethmoidal artery (AEA) is extremely rare.Case Presentation: A 25-year-old man experienced massive epistaxis due to a ruptured traumatic pseudoaneurysm of the AEA. The patient had suffered head and face trauma in a car accident. CT showed fractures of the frontal, ethmoidal, and maxillary bones, and he was managed conservatively. Nine days after the injury, he had sudden, massive epistaxis. Angiography showed a right AEA aneurysm, which was treated successfully with transarterial embolization using n-butyl-2-cyanoacrylate (NBCA).Conclusion: Although pseudoaneurysm of the AEA is a rare cause of epistaxis, it is important to consider this diagnosis, in addition to pseudoaneurysm of the SPA and ICA, when a patient has massive arterial epistaxis following a traumatic skull base fracture, especially if the fracture is adjacent to the ethmoid sinus. Transarterial embolization using glue is a feasible therapeutic option for this condition.

Skull Base Venous Anatomy Associated with Endoscopic Skull Base Neurosurgery: A Literature Review

Mizutani K, Akiyama T, Yoshida K, Toda M

World Neurosurgery (World Neurosurgery) 120 405 - 414 2018.12

Joint Work, ISSN 18788750

© 2018 Elsevier Inc. An understanding of the anatomy and function of the skull base venous channels is fundamentally important for safe performance of endoscopic surgery for skull base lesions. This review focuses on 4 skull base venous channels—namely, the intercavernous sinuses, basilar plexus, osseous veins, and inferior petroclival vein—because these have been less recognized by neurosurgeons than other major venous channels such as the inferior petrosal sinus. We reviewed the literature concerning these 4 venous channels and discussed their anatomy and function. The literature review was mainly based on an electronic search in PubMed using the following terms: “intercavernous sinus,” “basilar plexus,” “emissary veins,” “diploic vein,” “basilar plexus,” “intraosseous vein,” “inferior petroclival/petro-occipital vein,” and “transclival.” A total of 50 articles were included in this review. Detailed anatomic features of the 4 structures have been elucidated in the literature. All of these venous channels run along the skull base and have multiple connections with surrounding venous structures. Because of their location, they occasionally obstruct the surgical view and are sometimes implicated in intraoperative hemorrhage, air embolism during endoscopic skull base surgery, and postoperative hematoma. They usually function as a venous reservoir of cranial venous drainage; however, they are less often directly involved in normal brain perfusion. Knowledge about the functional and morphologic anatomy of the skull base venous channels is important for neurosurgeons to avoid unexpected complications during endoscopic skull base surgery.

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An analysis of the anatomic route of the hypoglossal nerve within the hypoglossal canal using dynamic computed tomography angiography in patients with anterior condylar arteriovenous fistulas

Oishi Y, Akiyama T, Mizutani K, Horiguchi T, Imanishi N, Yoshida K

Clinical Neurology and Neurosurgery (Clinical Neurology and Neurosurgery) 174 207 - 213 2018.11

Joint Work, ISSN 03038467

© 2018 Elsevier B.V. Objective: The venous outlet of anterior condylar arteriovenous fistulas (AC-AVFs) often empties into the anterior condylar vein (ACV). Hypoglossal nerve palsy is one of the major complications after transvenous embolization (TVE) for the AC-AVF within the hypoglossal canal. However, no studies have investigated the route of the hypoglossal nerve within the hypoglossal canal in AC-AVF. The aim of the current study is to retrospectively verify the anatomical route of the hypoglossal nerve within its canal using dynamic computed tomography angiography (CTA) in order to facilitate the safe TVE for AC-AVF. Patients and methods: We included five patients with AC-AVF from 2011 to 2017. Dynamic CTA was performed on all patients. When the ACV was well-visualized by dynamic CTA, the hypoglossal nerve could be recognized as a less-intense structure within the surrounding enhanced vasculatures and the nerve route within the canal was analyzed. We also analyzed the location of the fistulas by digital subtraction angiography and cone-beam computed tomography. Results: In all five patients, the filling defect of the hypoglossal nerve ran through the most caudal portion of the hypoglossal canal. The fistulous pouches were located in the hypoglossal canal in three cases, and in the jugular tubercle venous complex in two cases. In all three cases with AC-AVF in the hypoglossal canal, the fistulous pouches were located in the superior wall of the hypoglossal canal, which means superior to the ACV. We performed TVE in four patients and none developed post-therapeutic hypoglossal nerve palsy. Conclusion: In the current study, dynamic CTA is useful for detecting the hypoglossal nerve within the hypoglossal canal. The hypoglossal nerve usually ran the bottom of its canal and the fistulous pouches were usually located at the superior aspect of the canal opposite side to the hypoglossal nerve. Accordingly, the selective embolization within the fistulous pouch located in the superior aspect of the ACV including jugular tubercle venous complex can reduce the risk of hypoglossal nerve palsy.

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Pros and cons of using ORBEYE™ for microneurosurgery

Takahashi S, Toda M, Nishimoto M, Ishihara E, Miwa T, Akiyama T, Horiguchi T, Sasaki H, Yoshida K

Clinical Neurology and Neurosurgery (Clinical Neurology and Neurosurgery) 174 57 - 62 2018.11

Joint Work, ISSN 03038467

© 2018 Elsevier B.V. Objective: To evaluate the pros and cons of using a newly developed microscope, ORBEYE™, during microneurosurgery. Patients and methods: ORBEYE™ use in 14 microneurosurgical procedures was retrospectively assessed by nine neurosurgeons after the procedure. A questionnaire comprising 20 questions was designed and used for evaluation. Results: Compared with the current gold standard, the binocular microscope, ease of setting up the equipment was scored the highest, whereas ease of conducting surgery in a position of an assistant was scored the lowest. Among characteristics of ORBEYE™ itself, the space-saving feature was scored the highest and was followed by the ability to perform procedures in a comfortable position. The only characteristic that was rated below average was ease of operation in a position of an assistant. Neurosurgeons with greater experience (more than five procedures using ORBEYE™) provided significantly higher scores (p = 0.0196) for characteristics of ORBEYE™ itself compared with neurosurgeon with fewer ORBEYE™ experience. Conclusions: The main benefits of the ORBEYETM are its compact size and freedom from focusing through the eye lens of a conventional binocular microscope. However, it appears to be disadvantageous for operating in a position of an assistant because the surgical field has a rotated view on the monitor from a position of an assistant. Nonetheless, because of certain advantages, we believe the ORBEYE™ could be of additional help to use of conventional binocular microscope at the moment and will facilitate microneurosurgery in the future.

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Combined Endoscopic Endonasal and Video-microscopic Transcranial Approach with Preoperative Embolization for a Posterior Pituitary Tumor

Yoshida K, Toda M, Akiyama T, Takahashi S, Nishimoto M, Ozawa H, Ikari Y, Yoshida K

World Neurosurgery (World Neurosurgery) 119 201 - 208 2018.11

Joint Work, ISSN 18788750

© 2018 Elsevier Inc. Background: Posterior pituitary tumor is rare, and its optimal surgical strategy is undetermined. Surgical removal of posterior pituitary tumors is often complicated by their hypervascularity. Prevention and preparation for excessive hemorrhage is crucial for safe resection. Case Description: A 69-year-old woman presented with bitemporal hemianopsia and was found to have a sellar tumor with suprasellar extension, resembling a pituitary adenoma. Microscopic transsphenoidal resection was attempted but was interrupted by a massive intraoperative hemorrhage. Pathologic diagnosis was a spindle cell oncocytoma, and she was referred to our institution. She underwent preoperative embolization to decrease tumor vascularity, and resection was performed using a combined endoscopic endonasal and video-microscopic transcranial approach, using a 4K three-dimensional (3D) video microscope. The final diagnosis was a posterior pituitary tumor with immunopositivity for thyroid transcription factor-1, with preferred interpretation as a pituicytoma. Conclusions: A combined endonasal and transcranial approach with preoperative embolization is a useful strategy for hypervascular posterior pituitary tumors. A 4K 3D video microscope is compact, and it provides high-resolution images, contributing larger surgical space and facilitating a multi-team surgery.

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Primary Intracranial Rhabdomyosarcoma in the Cerebellopontine Angle Resected After Preoperative Embolization

Keisuke Yoshida, Tomoru Miwa, Takenori Akiyama, Masaaki Nishimoto, Dai Kamamoto, Kazunari Yoshida

World Neurosurgery (Elsevier Inc.) 116 110 - 115 2018.08

Research paper (scientific journal), Joint Work, ISSN 18788750

Background: Primary intracranial rhabdomyosarcoma is a very rare malignant tumor. Owing to moderately vascular and firm characteristics of the tumor, complete removal without complications is often difficult. In pediatric patients, the volume of total blood is less than in adults, and minimal intraoperative hemorrhage is desirable. Case Description: A 6-year-old boy presented with ataxia and was found to have a large cerebellopontine angle tumor and hydrocephalus. The patient underwent preoperative coil embolization of the anterior inferior cerebellar artery to decrease tumor vascularity, and gross total removal was achieved on the same day via a suboccipital approach. Pathologic diagnosis was rhabdomyosarcoma. Conclusions: Successfully resection of primary intracranial rhabdomyosarcoma was achieved after preoperative embolization. Tumor vascularity was significantly reduced, and gross total removal was achieved safely with less hemorrhage.

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Preoperative Assessment of Pathologic Subtypes of Meningioma and Solitary Fibrous Tumor/Hemangiopericytoma Using Dynamic Computed Tomography: A Clinical Research Study.

Nobuhiko Arai, Katsuhiro Mizutani, Satoshi Takahashi, Yukina Morimoto, Takenori Akiyama, Takashi Horiguchi, Hatano Mami, Kazunari Yoshida

World neurosurgery (World Neurosurgery) 115 e676 - e680 2018.07

Joint Work, ISSN 18788750

BACKGROUND: Solitary fibrous tumors (SFTs)/hemangiopericytomas (HPCs) are highly vascularized tumors well known for malignant, invasive, and highly vascular features. To date, several studies have reported the preoperative imaging findings of SFTs/HPCs. In this study, computed tomography (CT) tumor values acquired from dynamic CT scan were selected to determine the tumor pathology of highly vascular tumors, such as SFTs/HPCs. METHODS: We conducted a retrospective study on patients with pathologically diagnosed meningiomas and SFTs/HPCs who had undergone a dynamic contrast CT scan. We assessed and compared the CT values of these tumors according to the pathology. RESULTS: From a total of 34 patients, 30 patients with meningiomas and 4 patients with HPCs were included. The mean CT values of SFTs/HPCs and angiomatous meningioma were statistically significantly higher than those of the other meningioma subtypes (P = 0.003). We also performed receiver operating characteristic curve analyses to detect an appropriate cutoff point for the CT value to differentiate tumor pathology, and the calculated threshold was 161 Hounsfield units (HU) (sensitivity, 100%; specificity, 75%; area under the curve, 0.87; 95%, CI 0.75-0.99). CONCLUSIONS: This study showed that obtaining a CT value is useful in determining highly vascular tumor pathology preoperatively. When considering neurosurgical extra-axial tumor removal, and when the CT value of tumors is >161 HU, then highly vascular tumors such as SFTs/HPCs or angiomatous meningiomas are likely, and this should be considered prior to surgical intervention and for risk assessment.

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Intraosseous venous structures adjacent to the jugular tubercle associated with an anterior condylar dural arteriovenous fistula

Katsuhiro Mizutani, Takenori Akiyama, Yasuhiro Minami, Masahiro Toda, Hirokazu Fujiwara, Masahiro Jinzaki, Kazunari Yoshida

Neuroradiology (Springer Verlag) 60 ( 5 ) 487 - 496 2018.05

Research paper (scientific journal), Joint Work, ISSN 00283940

Purpose: Although involvement of the osseous component with an anterior condylar dural arteriovenous fistula (AC-DAVF) has been frequently described, osseous venous structures in which AC-DAVFs develop have not been fully elucidated. We investigated osseous venous structures adjacent to the hypoglossal canal in normal controls and patients with AC-DAVFs. Methods: The study included 50 individuals with unruptured aneurysms as normal controls and seven patients with AC-DAVFs. Osseous venous structures adjacent to the hypoglossal canal in normal controls were analyzed using computed tomography (CT) digital subtraction venography. In patients with AC-DAVFs, the fistulous pouches, draining veins, and surrounding venous structures were examined using cone beam CT. Results: In 46.0% of laterals in normal controls, osseous venous structures were visualized within the jugular tubercle superomedially to the hypoglossal canal. We named these structures the jugular tubercle venous complex (JTVC). The JTVC was always continuous with the anterior condylar vein and was sometimes connected to surrounding venous channels. We detected nine fistulous pouches in the seven patients with AC-DAVFs. The fistulous pouches were in the JTVC (33.3%), anterior condylar vein (33.3%), and other venous channels within the exoccipital region (33.3%). Conclusion: Although the JTVC is a venous structure frequently found in normal people, it had not been investigated until now. The venous channel between the anterior condylar vein and JTVC is a common origin site for AC-DAVFs, and it was associated with 66.6% of the AC-DAVF cases in the current study.

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The analysis of the cerebral venous blood volume in cavernous sinus using 320 row multi-detector CT

Katsuhiro Mizutani, Masahiro Toda, Yumi Yajima, Takenori Akiyama, Hirokazu Fujiwara, Kazunari Yoshida, Masahiro Jinzaki

Clinical Neurology and Neurosurgery (Elsevier B.V.) 167 11 - 16 2018.04

Research paper (scientific journal), Joint Work, ISSN 03038467

Objectives: : Functional venous anatomy in the brain has been mostly understood from the morphological and embryological points of view and no published study has directly evaluated the blood flow volume of cerebral small veins. We developed a method to directly evaluate the relative blood volume in small venous channels using multi-detector computed tomography (CT) and applied it to evaluate the blood volume in each tributary of the cavernous sinus, which plays an important role in cerebral venous drainage. Patients and Methods: : Ten patients with small brain tumors who had normal venous anatomy were included in the present study. All of them underwent preoperative 320-row multi-detector CT. After injecting the contrast bolus, we measured the Hounsfield units (HUs) at 10 time point over 60 s in each tributary of the cavernous sinus. The gamma distribution fitting to each HU enabled us to obtain a time-density curve and determine the relative venous volume in each venous channel. Results: : In terms of blood volume, the superficial middle cerebral vein and inferior petrosal sinus were the largest inflow and outflow channels of the cavernous sinus and accounted for 36.1% and 24.7% of its inflow and outflow on average, respectively. The superior orbital vein did not contribute to the blood volume passing through the cavernous sinus in the current study. Conclusions: : The present study allowed us to determine the relative blood volume in each tributary of the cavernous sinus, which was very useful to understand the physiological actual venous drainage pattern concerning the cavernous sinus in normal anatomy.

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Fate of the three embryonic dural sinuses in infants: the primitive tentorial sinus, occipital sinus, and falcine sinus

Katsuhiro Mizutani, Tomoru Miwa, Takenori Akiyama, Yoshiaki Sakamoto, Hirokazu Fujiwara, Kazunari Yoshida

Neuroradiology (Springer Verlag) 60 ( 3 ) 325 - 333 2018.03

Research paper (scientific journal), Joint Work, ISSN 00283940

Purpose: The primitive tentorial, occipital, and falcine sinuses are thought to attain the adult pattern or regress between the fetal stage and adulthood. The anatomy of these three primitive dural sinuses has seldom been studied in the infant population, and it remains unclear when these dural sinuses reach the adult condition. Using computed tomography digital subtraction venography (CT-DSV), we analyzed the anatomy of these embryonic dural sinuses in infants. Methods: We included 13 infants who underwent CT-DSV prior to neurosurgery and 35 cases with unruptured cerebral aneurysms as normal adult controls. Three embryonic dural sinuses, i.e., the primitive tentorial, occipital, and falcine sinuses, were retrospectively analyzed in CT-DSV images of infants and adults. We also analyzed the drainage patterns of the superficial middle cerebral vein (SMCV), determined by the connection between the primitive tentorial sinus and the cavernous sinus. Results: The primitive tentorial, occipital, and falcine sinuses were present in 15.4%, 46.2%, and none of the infants, respectively, and in 10.0, 8.6, and 2.9% of the adults, respectively. The difference in SMCV draining pattern between infants and adults was insignificant. The incidence of the occipital sinus was significantly higher in infants than in adults. Conclusions: The connection between the primitive tentorial sinus and the cavernous sinus appears to be established before birth. The occipital sinus is formed at the embryonic stage and mostly regresses after infancy. The falcine sinus is usually obliterated prenatally. Our findings form the basis for interventions by pediatric interventional neuroradiologists and neurosurgeons.

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High detectability of non-contrast-enhanced MR angiography using a silent scan for screening of cerebral arteriovenous malformations in HHT patients

Akiyama Takenori, Fujiwara Hirokazu, Jinzaki Masahiro, Yoshida Kazunari

ANGIOGENESIS 21 ( 1 ) 138 - 138 2018.02

Joint Work, ISSN 0969-6970

Advantages of Staged Angioplasty in a Patient with Internal Carotid Artery Pseudo-Occlusion Besides Prevention of Cerebral Hyperperfusion Syndrome

Satoshi Takahashi, Takenori Akiyama, Jin Nakahara, Takahito Yoshizaki, Norihiro Suzuki, Kazunari Yoshida

World Neurosurgery (Elsevier Inc.) 109 409 - 412 2018.01

Research paper (scientific journal), Joint Work, ISSN 18788750

Background Staged angioplasty for carotid artery stenosis has been reported to be effective in preventing postoperative cerebral hyperperfusion syndrome (CHS) in patients with severe carotid stenosis
thus, it is also recommended for patients with internal carotid artery (ICA) pseudo-occlusion, the treatment strategy for which is controversial. Case Description This study reports the case of an Asian man in his 50s who had motor aphasia and right-side weakness caused by pseudo-occlusion of the left ICA. After medical treatment, he underwent a staged angioplasty. After the first stage of percutaneous transluminal angioplasty, anterograde blood flow to the left ICA increased but the distal ICA remained partially collapsed. Initially, the second stage of carotid artery stenting (CAS) was planned for 2 weeks after the first stage
however, hemorrhagic infarction was observed the day before the CAS, and it was postponed by 2 weeks, after adjustment of antiplatelet therapy. At the time of the CAS, the diameter of the initially collapsed left distal ICA was remodeled and it was fully dilated
thus, we used a balloon-type embolic protection device and conducted CAS successfully without apparent embolic complications. The postoperative course was uneventful. The patient did not develop CHS. Conclusions Besides preventing CHS, staged angioplasty has advantages when used for treating patients with ICA pseudo-occlusions in that the extent of dilation of the distal ICA after percutaneous transluminal angioplasty can be confirmed and the development of a possible hemorrhagic infarction can be assessed before stent placement.

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Changes in Utility and Limits of Combined Microsurgical and Endovascular Treatment for Complex Cerebrovascular Disease before and after the Introduction of the Hybrid Operating Room

HORIGUCHI Takashi, AKIYAMA Takenori, TAKAHASHI Satoshi, OHIRA Takayuki, YOSHIDA Kazunari

Surgery for Cerebral Stroke (The Japanese Society on Surgery for Cerebral Stroke) 46 ( 6 ) 453 - 461 2018

ISSN 0914-5508

Here we investigated the changes in utility and limits of combined microsurgical and endovascular treatment for complex cerebrovascular disease before and after the introduction of the hybrid operating room (HOR) in our department. Since 2006, a total of 17 patients (cerebral aneurysm in 12, cerebral arteriovenous malformation in 5) underwent integrated microsurgery with endovascular treatment. In 3 of 11 patients treated before the introduction of HOR, certain problems such as time consumption during patient transfer, disconnected workflow, and complicated operation due to poor quality of support equipment occurred. In contrast, all 6 operations in the HOR were uncomplicated. All therapeutic steps including anesthesia management were planned in a single session. In conclusion, HOR provides a safe and smooth workflow in combined microsurgical and endovascular treatment for complex cerebrovascular diseases.

microRNA expression profiling in serum of patients with subarachnoid hemorrhage

Takahashi S, Akiyama T, Horiguchi T, Mizutani K, Mihara K, Yanagisawa K, Akaji K, Mihara B, Yoshida K

CEREBROVASCULAR DISEASES 45 247 - 247 2018

Joint Work, ISSN 1015-9770

The analysis of the cerebral venous blood volume in small channels- application to the tributaries of cavernous sinus

Mizutani K, Toda M, Yajima Y, Akiyama T, Fujiwara H, Yoshida K, Jinzaki M

CEREBROVASCULAR DISEASES 45 472 - 472 2018

Joint Work, ISSN 1015-9770

The usefulness of HOR for complicated cerebrovascular surgery

堀口崇, 秋山武紀, 高橋里史, 大平貴之, 吉田一成

脳卒中の外科 46 453 - 461 2018

Research paper (scientific journal), Joint Work, Accepted

Micro AVMの検出におけるultra-short TE MRI(silent MRA)の有用性

荒井信彦, 秋山武紀, 藤原広和, 陣崎雅弘, 吉田一成

脳血管内治療 ((NPO)日本脳神経血管内治療学会) 2 ( Suppl. ) S235 - S235 2017.11

Accepted, ISSN 2423-9119

再狭窄、最大内膜中膜複合体圧(max-IMT)、全身他臓器疾患合併から検討したCEAの長期成績

HORIGUCHI TAKASHI

脳卒中の外科 45 ( 5 ) 370 - 377 2017.10

Accepted

Postnatal delayed exacerbation of dural sinus malformation associated with brainstem cavernous malformations: A case report.

Katsuhiro Mizutani, Tomoru Miwa, Takenori Akiyama, Tokunori Kanazawa, Hideaki Nagashima, Kei Miyakoshi, Yasunari Niimi, Kazunari Yoshida

Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences 23 ( 5 ) 510 - 515 2017.10

Dural sinus malformation (DSM) is a rare paediatric vascular malformation characterised by abnormal dilation of the posterior dural sinus. Owing to its rarity, the pathophysiology of DSM has not been fully elucidated. We report a case of prenatally diagnosed DSM with an unusual clinical course. We detected DSM in a male foetus in the 26th week of gestation by using foetal ultrasonography. Although the DSM regressed during the foetal stage and the arteriovenous shunt was insignificant in the neonate, the shunt rapidly developed four months after birth. The neonate also had postnatal de novo brainstem cavernous malformation (CM), which also developed rapidly, supposedly due to the aggravated venous hypertension resulting from the DSM. We successfully treated the aggravated shunts by endovascular transarterial and transvenous embolisation six times over two years and, subsequently, the clinical condition and the size of the brainstem CM became stable. The DSM and CM seemed to have a metameric origin. Such aberrant cases could help to further the understanding of DSM.

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Analysis of the venous channel within the clivus using multidetector computed tomography digital subtraction venography.

Katsuhiro Mizutani, Masahiro Toda, Jun Kurasawa, Takenori Akiyama, Hirokazu Fujiwara, Masahiro Jinzaki, Kazunari Yoshida

Neuroradiology 59 ( 3 ) 213 - 219 2017.03

PURPOSE: Although neuroradiologists and skull base neurosurgeons are aware of the existence of veins within the clivus, such vessels have seldom been described in the literature. The aim of the present study is to elucidate the detailed venous structure of the clivus. METHODS: Computed tomography digital subtraction venography (CT-DSV) images of 50 unruptured aneurysm cases were examined retrospectively. RESULTS: Eighteen emissary veins were identified in 14 (28.0%) cases. A half of the emissary veins connected the inferior petrosal sinus with the inferior petro-occipital vein (IPOV) in the middle clivus. The clival diploic vein (CDV) was identified in 14.0% of cases, 42.9% of which had the clivus of the presellar type. The CDV was connected to the posterior intercavernous sinus or the rostral end of the basilar plexus superiorly, and was connected to the IPOV, anterior condylar vein, marginal sinus, or the anterior condylar confluence. CONCLUSION: The CDV provides collateral channels between the cavernous sinus and the internal jugular vein and the inferior petrosal sinus and the IPOV. Understanding of the emissary veins in the clivus and the CDV is valuable for skull base surgery, especially for endonasal endoscopic skull base procedures.

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The Coexistence of Extradural Arteriovenous Fistula and Soft Tissue Arteriovenous Malformation Within the Same Metamere.

Nobuhiko Arai, Takenori Akiyama, Kazunari Yoshida

World neurosurgery 98 877.e1-877.e7 - 877.e7 2017.02

Accepted, ISSN 1878-8750

BACKGROUND: Spinal arteriovenous shunts are a common spinal vascular disorder. However, they can have a misleading clinical presentation and poor prognosis. They are classified into 4 types according to shunt points and drainage route, among which extradural arteriovenous fistula (eAVF) is the most rare, comprising only 1% of all spinal arteriovenous shunts. We report an extremely rare case of coexistent eAVF at the craniocervical junction and soft tissue arteriovenous malformation within the same metamere. CASE DESCRIPTION: A 30-year-old man presented with neck pain. T2-weighted magnetic resonance imaging revealed a flow void at the right craniocervical junction compressing the spinal cord. Angiography revealed eAVF at the craniocervical junction. The patient was treated via transvenous embolization. After the procedure, shunt flow and symptoms markedly decreased. During the operation, an extracranial arteriovenous malformation under the occipital skin was detected immediately after occluding the shunt point. CONCLUSIONS: This case indicates that transvenous embolization can be an effective treatment for eAVF and supports some hypotheses of arteriovenous malformation development. Additionally, it emphasizes the importance of examining a lesion with multiple modalities, including angiography, three-dimensional angiography, and cone-beam computed tomography, to understand the anatomy of the lesion.

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Transvenous Embolization of the Basilar Plexus Before Endoscopic Transsphenoidal Transclival Surgery

Katsuhiro Mizutani, Takenori Akiyama, Masahiro Toda, Tokunori Kanazawa, Dai Kamamoto, Kazunari Yoshida

WORLD NEUROSURGERY (ELSEVIER SCIENCE INC) 97 2017.01

Accepted, ISSN 1878-8750

BACKGROUND: The endoscopic transclival approach is a method for reaching the anterior side of the brainstem. In making this approach, bleeding from the basilar plexus is often observed when cutting the dura overlying the clivus. Controlling such bleeding is essential.
CASE DESCRIPTION: We performed a transvenous embolization of the basilar plexus before making the transclival approach. After embolization, bleeding from the basilar plexus during the operation decreased considerably.
CONCLUSIONS: To our knowledge, this is the first report of transvenous embolization of the basilar plexus. If the basilar plexus is well developed on preoperative computed tomographic venography or digital subtraction angiography, this procedure is useful for controlling bleeding during endoscopic transclival surgery.

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Endonasal endoscopic approach for a giant cavernous sinus meningioma that extended to the middle cranial fossa with preoperative embolization

Tamura R, Toda M, Kohno M, Ozawa H, Tomita T, Akiyama T, Ogawa K, Yoshida K

Interdisciplinary Neurosurgery 6 20 - 22 2016.12

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硬膜動静脈瘻診療におけるultra-short TE MRI(silent MRA)の有用性

荒井信彦, 秋山武紀, 藤原広和, 陣崎雅弘, 吉田一成

脳血管内治療 ((NPO)日本脳神経血管内治療学会) 1 ( Suppl. ) S293 - S293 2016.11

Accepted, ISSN 2423-9119

頸椎硬膜外動静脈瘻と軟部組織動静脈奇形が同一metamere内に発生した一例

荒井信彦, 秋山武紀, 美原貫, 水谷克洋, 吉田一成

脳血管内治療 ((NPO)日本脳神経血管内治療学会) 1 ( Suppl. ) S148 - S148 2016.11

Accepted, ISSN 2423-9119

Marfan症候群に生じたくも膜下出血に対し開頭クリッピングを施行した1例ー症例報告と文献的考察ー

HORIGUCHI TAKASHI

脳卒中の外科 44 ( 4 ) 307 - 310 2016.08

Accepted

経過観察となった5 mm未満の未破裂脳動脈瘤に対する治療方針ー治療介入を決定する因子と時期についてー

HORIGUCHI TAKASHI

脳卒中の外科 44 ( 4 ) 276 - 282 2016.08

Accepted

The remnant of primary head sinus found in the case of dural arteriovenous fistula: A case report.

Katsuhiro Mizutani, Takenori Akiyama, Kazunari Yoshida

Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences 22 ( 4 ) 452 - 6 2016.08

In the embryo, the primary head sinus (PHS) is the first venous drainage channel in the craniocervical region. During embryonic development, this channel regresses and usually disappears completely; accordingly, a remnant of the PHS is an extremely rare condition and has been described in only a few previous studies. Here, we report a case of remnant of the PHS with a dural arteriovenous fistula (dAVF) in an adult. The remnant of the PHS had penetrated the petrous bone to run from the middle fossa to the jugular bulb and served as a drain for the middle fossa dAVF. We used digital subtraction angiography and reconstructed cone-beam computed tomography in 3D rotational angiography to obtain detailed anatomic information about the remnant PHS and additionally scrutinised and discussed its features.

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A ruptured aneurysm in the vasa corona at the craniocervical junction with dysgenesis of the posterior inferior cerebellar artery.

Katsuhiro Mizutani, Takenori Akiyama, Dai Kamamoto, Hideaki Nagashima, Kazunari Yoshida

BJR case reports 2 ( 3 ) 20160004 - 20160004 2016

This paper reports the case of a ruptured aneurysm in the vasa corona at the craniocervical junction with dysgenesis of the posterior inferior cerebellar artery (PICA). Dysgenesis of the proximal PICA in the present case caused the development of a pial anastomosis in the vasa corona, resulting in the formation of an aneurysm because of increased haemodynamic stress at the vasa corona. The aneurysm was successfully treated with transarterial coil embolization. The clinical entity in the present case is extremely rare and it is important to consider an aberrant vascular anomaly as the cause of an isolated spinal aneurysm.

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The process of change in hemodynamics after revascularization in the ischemic brain

Shidoh, Satoka, Akiyama, Takenori, Horiguchi, Takashi, Ohira, Takayuki, Yoshida, Kazunari

NEUROREPORT (LIPPINCOTT WILLIAMS & WILKINS) 26 ( 11 ) 629 - 633 2015.08

Research paper (scientific journal), Joint Work, ISSN 0959-4965

In patients with a high-degree of internal carotid artery stenosis, cerebral hemodynamics and metabolism are compromised during ischemia. Revascularization improves cortical hemodynamics and oxygen metabolism during functional activity, but the process by which it occurs is still controversial. Therefore, using functional near-infrared spectroscopy (fNIRS), we investigated the process by which cerebral hemodynamics improve after revascularization surgery. Eight patients with severe carotid artery stenosis were examined using fNIRS during a motor task before and after surgery. We evaluated postoperative changes in total hemoglobin and deoxyhemoglobin (HbR), at 2 weeks after surgery, and again at 3 months after surgery. Parameters measured were the TTP0.7 (time to peak) value, defined as the time taken to reach 70% of the maximum total hemoglobin concentration, and the increase in HbR during the motor task. TTP0.7 was higher in four patients preoperatively, but this was no longer evident in two of the patients at 2 weeks after surgery. An increase in HbR during the task was observed in six patients before surgery, and was maintained at 2 weeks after surgery. However, in three of these patients, this increase was no longer evident 3 months later. These changes observed using fNIRS suggest that the increase in cerebral blood flow after revascularization surgery is followed by improvement in parenchymal vasodilation and neuronal oxygen metabolism. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

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Clinical utility of triptans in the management of headache attributed to dural arteriovenous fistula involving the cavernous sinus

Osaka, Mayuko, Shibata, Mamoru, Oki, Koichi, Yamada, Satoshi, Kufukihara, Kenji, Akiyama, Takenori, Yoshida, Kazunari, Suzuki, Norihiro

JOURNAL OF THE NEUROLOGICAL SCIENCES (ELSEVIER SCIENCE BV) 349 ( 1-2 ) 260 - 261 2015.02

Research paper (scientific journal), Joint Work, ISSN 0022-510X

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Endovascular embolization of an external carotid-retromandibular arteriovenous fistula using the Amplatzer vascular plug

TOMIO Ryosuke, AKIYAMA Takenori, NAKATSUKA Seishi, NAGASHIMA Hideaki, YAMADA Satoshi, YOSHIDA Kazunari

Journal of Neuroendovascular Therapy (The Japanese Society for Neuroendovascular Therapy) 2015

ISSN 1882-4072

Objective: The Amplatzer vascular plug (AVP) is a new embolic device with advantages in embolization of high-flow vessels. We report a case involving implantation of an AVP into the retromandibular vein and coil-embolization of an arteriovenous fistula (AVF).Case presentation: We present the case of a 31-year-old woman with an external carotid artery (ECA)-retromandibular vein AVF. She complained of pulsatile tinnitus after a sagittal split-ramus osteotomy. The high-flow left ECAretromandibular vein AVF was depicted in the arterial phase using selective external carotid angiography (ECAG). Endovascular embolization treatment of the fistula using an AVP and coils was planned. We initially intended to introduce the AVP into the fistula via a transvenous route through the left external jugular vein, but could not pass the 5-Fr guiding catheter round the hairpin curve between the fistula and ECA. We therefore changed treatment strategy, placing an 8 mm AVP into the retromandibular vein. Fistula closure was almost obtained after implantation, but shunt flow from a narrow channel remained. We then embolized the fistula using coils, from the AVP to the fistula inlet. The fistula was occluded using five coils.Conclusion: We treated the patient with implantation of an AVP in the retromandibular vein and coil-embolization of the AVF. Advantages of the AVP are its stability for high-flow vessel occlusion and its cost-effectiveness when compared with coils. However, this device has disadvantages in the ease of its delivery to distal vessels. Therefore, using this device in craniofacial lesions needs technical refinement.

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Usefulness of facial nerve monitoring for confirmation of greater superficial petrosal nerve in anterior transpetrosal approach

Tomio, Ryosuke, Akiyama, Takenori, Ohira, Takayuki, Horikoshi, Tomo, Yoshida, Kazunari

ACTA NEUROCHIRURGICA (SPRINGER WIEN) 156 ( 10 ) 1847 - 1852 2014.10

Research paper (scientific journal), Joint Work, Accepted, ISSN 0001-6268

The greater superficial petrosal nerve (GSPN) is especially important in anterior transpetrosal approach (ATPA) as the most reliable superficial landmark of Kawase's triangle. The GSPN can be considered as the superficial lateral border of anterior petrosectomy on the middle fossa to avoid internal carotid artery (ICA) injury. Although experienced operators can find the GSPN, its confirmation is not always easy to achieve.
We introduce our recent GSPN confirmation methods using facial nerve monitoring. In 10 recent cases, antidromic GSPN stimulation and free-running facial muscle electromyography (EMG) monitoring were performed.
Facial nerve evoked-EMG by antidromic GSPN stimulation confirmed the location of the GSPN course with precision in all cases. Free-running facial muscle EMG informed the mechanical stress of facial nerves through the GSPN. There was no postoperative facial palsy or dry eye in these cases.
GSPN confirmation and preservation are not always easy to achieve. These monitoring methods are useful for the confirmation of the GSPN, which is a landmark for safe extradural anterior petrosectomy, and for the preservation of the GSPN itself.

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Cerebral Perfusion Change of Venous Hypertension on Near-Infrared Spectroscopy Signals after Operation for Dural Arteriovenous Fistula

Shidoh, Satoka, Akiyama, Takenori, Ohira, Takayuki, Yoshida, Kazunari

JOURNAL OF STROKE & CEREBROVASCULAR DISEASES (ELSEVIER SCIENCE BV) 23 ( 5 ) 823 - 828 2014.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 1052-3057

A dural arteriovenous fistula (AVF) is an arteriovenous shunt in the dura and is associated with a risk of intracranial hemorrhage and neurologic deficit. The morbidity of this disease depends on venous hypertension, and the classification of this disease is based on the pattern of venous drainage. The pattern of venous drainage relates to the clinical features of the disease, especially to the probability of intracranial hemorrhage. We report 1 case of dural AVF with retrograde leptomeningeal venous drainage. Cerebral hemodynamics were monitored using near-infrared spectroscopy imaging before, during, and after the 2-stage operative treatment. Preoperative functional near-infrared spectroscopy (fNIRS) showed an increase in deoxyhemoglobin (HbR) during a motor task. After partial coil embolization of the shunt points (stage 1), HbR increased during the first half of the task and decreased later, whereas oxyhemoglobin (HbO(2)) decreased in the first half of the task and increased later. After complete embolization (stage 2), fNIRS showed a pattern similar to that of a normal adult. The patient's symptoms improved gradually, and angiography showed a reduction of the retrograde venous drainage and venous congestion after this 2-stage operation. The reduction in venous hypertension may be the underlying mechanism behind the changes observed with fNIRS.

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Procalcitonin as an Early Diagnostic Marker for Ventriculoperitoneal Shunt Infections

Tomio, Ryosuke, Akiyama, Takenori, Shibao, Shunsuke, Yoshida, Kazunari

SURGICAL INFECTIONS (MARY ANN LIEBERT, INC) 14 ( 5 ) 433 - 436 2013.10

Research paper (scientific journal), Joint Work, ISSN 1096-2964

Background: Procalcitonin (PCT) has been considered a more reliable marker than others because of its specificity for bacterial infection. Methods: Case report and review of the literature. Results: A 50-year-old male was diagnosed with subarachnoid hemorrhage, intraventricular hemorrhage, and intracerebral hemorrhage. We performed a ruptured aneurysm clipping and left unilateral external ventricular drainage. We also performed ventriculoperitoneal (VP) shunt placement in the course; however, VP shunt infection was indicated by fever, increased C-reactive protein concentration and leukocytosis. The cerebrospinal fluid culture showed methicillin-resistant Staphylococcus epidermidis but the serum PCT concentration was quite low. Conclusions: Although PCT is considered a more reliable serological marker of bacterial meningitis in several reports, the serum PCT concentration did not reflect the bacterial VP shunt infection that was present in our case.

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Optic nerve seeding of atypical meningiomas presenting with subacute visual loss: 2 case reports with genetic characterization

Kitamura, Yohei, Akiyama, Takenori, Sasaki, Hikaru, Hayashi, Yuichiro, Yoshida, Kazunari

JOURNAL OF NEUROSURGERY (AMER ASSOC NEUROLOGICAL SURGEONS) 119 ( 2 ) 494 - 498 2013.08

Research paper (scientific journal), Joint Work, Accepted, ISSN 0022-3085

Meningiomas rarely cause CSF dissemination, and CSF seeding to the optic nerve (ON) is extremely rare. This is the first report of 2 cases of atypical meningioma with subacute visual loss due to ON seeding. The authors present the genetic characteristics of these atypical meningiomas with CSF dissemination. The patient in Case 1 was a 36-year-old woman with a 1.5-cm mass within the left ON, and the patient in Case 2 was a 70-year-old woman with a 0.9-cm mass around the right ON. Both individuals had undergone multiple surgeries for primary lesions and local recurrent lesions. They presented with subacute visual loss, and both tumors were completely resected. The pathological diagnosis was atypical meningioma with high MIB-1 indices and p53-positive cell ratios in each case. Comparative genomic hybridization showed significant chromosomal copy number alterations similar to the results of previous surgeries, confirming that the tumors were disseminated lesions. The present findings suggest that genetic characteristics, such as 1p and 10qcen-23 losses and 17q and 20 gains, shared by the 2 cases might be associated with CSF dissemination of meningiomas.

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Whole-brain CT digital subtraction angiography of cerebral dural arteriovenous fistula using 320-detector row CT

Fujiwara, Hirokazu, Momoshima, Suketaka, Akiyama, Takenori, Kuribayashi, Sachio

NEURORADIOLOGY (SPRINGER) 55 ( 7 ) 837 - 843 2013.07

Research paper (scientific journal), Joint Work, ISSN 0028-3940

The purpose of this study was to evaluate the usefulness of CT digital subtraction angiography (CTDSA) by using 320-detector row CT in the diagnosis and classification of cerebral dural arteriovenous fistula (dAVF) and comparing it with DSA as the standard reference.
A total of 29 CTDSA/DSA from 25 patients with dAVF were retrospectively evaluated by two neuroradiologists. The presence, Cognard classification, and feeding arteries of dAVFs on CTDSA were assessed according to DSA.
DSA depicted 33 dAVFs in 28 cases. By consensus reading, CTDSA correctly detected 32 dAVFs in 27 cases and properly graded 31 lesions. The intermodality agreement for the presence and classification of dAVFs was excellent (kappa = 0.955 and 0.921, respectively). CTDSA detected 77 of 109 feeding arteries (70.6 %) in 25 cases. The intermodality agreement for the feeding arteries was good (kappa = 0.713).
Although CTDSA is limited in temporal and spatial resolution in comparison with DSA, it is an effective non-invasive tool for the detection and classification of dAVF.

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Recanalisation of spontaneously occluded vertebral artery dissection after subarachnoid haemorrhage

Akiyama, Takenori, Onozuka, Satoshi, Horiguchi, Takashi, Yoshida, Kazunari

NEUROSURGICAL REVIEW (SPRINGER) 35 ( 4 ) 615 - 619 2012.10

Research paper (scientific journal), ISSN 0344-5607

Spontaneous occlusion is a rare manifestation of ruptured vertebral artery dissection (VAD). Its natural history and treatment strategy have yet to be established due to its rarity. Here, we report five lesions involving spontaneous occlusion of VAD after subarachnoid haemorrhage, among which three lesions showed recanalisation. Based on our experience and previous reports, spontaneous occlusion of ruptured VAD can be classified into two groups-one group with occlusion in the acute stage with a high incidence of recanalisation and another group with occlusion in the chronic stage with a relatively low incidence of recanalisation. The underlying mechanism is likely different in each group, and treatment strategies should also be tailored depending on the pathophysiology.

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Optic nerve sheath solitary fibrous tumor

Kitamura, Yohei, Akiyama, Takenori, Hirose, Shigemichi, Yoshida, Kazunari

ACTA NEUROCHIRURGICA (SPRINGER WIEN) 154 ( 4 ) 633 - 635 2012.04

Research paper (scientific journal), Joint Work, ISSN 0001-6268

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Hemorrhagic onset of cerebellar pilocytic astrocytoma in an adult: a case report and review of the literature implying a possible relation of degenerative vascular changes to the massive intratumoral hemorrhage

Shibao, Shunsuke, Kimura, Tokuhiro, Sasaki, Hikaru, Fujiwara, Hirokazu, Akiyama, Takenori, Ueno, Mari, Shidoh, Satoka, Yoshida, Kazunari

BRAIN TUMOR PATHOLOGY (SPRINGER TOKYO) 29 ( 2 ) 96 - 102 2012.04

Research paper (scientific journal), Joint Work, ISSN 1433-7398

Pilocytic astrocytoma (PA) is a low-grade astrocytic tumor arising predominantly during the first two decades of life. Hemorrhagic onset of PAs is uncommon, and the etiology of hemorrhage remains unclear. Here we report a case of hemorrhagic onset of cerebellar PA in a 29-year-old man who presented with a week-long history of headache and gait instability. Computed tomography and magnetic resonance imaging revealed a hemorrhagic tumor located in the right cerebellar hemisphere, and total resection was performed. Histological examination showed bipolar glial cell proliferation in a biphasic pattern in a compact area and a loose microcystic area with Rosenthal fibers and eosinophilic granular bodies, indicating PA. Prominent changes in tumor vasculature, including aggregation of sclerotic thick-walled and ectatic thin-walled vessels, was observed, and nodules of thrombi containing complex vascular proliferation suggesting recanalized thrombi formed in partially ruptured vessels were also found. Thus, rupture of these abnormal vessels appeared to be the cause of hemorrhage. Review of the literature revealed that age distribution of patients with hemorrhagic PAs tends to be older than that of patients with general PAs. These findings imply a possibility that degenerative changes in blood vessels in long-standing PAs might be related to the mechanisms of spontaneous intratumoral hemorrhage.

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Severe Parkinsonism Following Endoscopic Third Ventriculostomy for Non-communicating Hydrocephalus -Case Report-

Akiyama, Takenori, Tanizaki, Yoshio, Akaji, Kazunori, Hiraga, Kenji, Akiyama, Takekazu, Takao, Masaki, Ohira, Takayuki

NEUROLOGIA MEDICO-CHIRURGICA (JAPAN NEUROSURGICAL SOC) 51 ( 1 ) 60 - 63 2011.01

Research paper (scientific journal), ISSN 0470-8105

A 23-year-old male with non-communicating hydrocephalus caused by intraventricular hemorrhage from an arteriovenous malformation was treated by endoscopic third ventriculostomy (ETV) after repeated ventricular cerebrospinal fluid drainage and removal of ventriculoperitoneal shunt due to infection. Postoperatively, the patient developed robust rigidity and akinesia with mutism, suggesting secondary parkinsonism. These symptoms showed marked improvement after administration of levodopa, and were not aggravated after discontinuation. The pathophysiology of this case might involve dysfunction of the dopaminergic system caused by repeated compression and release of the paraventricular white matter. Careful perioperative management not leading to excessive dilation of the the ventricles should be considered for ETV for non-communicating hydrocephalus to avoid this unexpected complication.

Early Embolizations for the Poorest Grade Patients with Ruptured Dissecting Aneurysms of the Vertebral Artery

AKAJI Kazunori, AKIYAMA Takenori, HIRAGA Kenji, TANIZAKI Yoshio, KOJIMA Atsuhiro, OKUI Syunichi

Nosotchu no Geka Kenkyukai koenshu (The Japanese Society on Surgery for Cerebral Stroke) 38 ( 1 ) 24 - 28 2010

ISSN 0914-5508

We report 5 patients (2 females and 3 males) with endovascular coil embolizations for ruptured dissecting aneurysms of the vertebral artery (VA). The age of the patients varies between 44 and 66 (mean 54.8) years. All patients had a Hunt and Kosnik Grade of V at admission. One patient had a dissecting aneurysm of the VA distal to the PICA. One patient had a dissecting aneurysm of the VA without the PICA. Three patients had a dissecting aneurysm of the VA involving the PICA. One patient with a dissecting aneurysm of the VA involving the PICA underwent proximal occlusion, and the other 4 patients underwent internal trapping. All patients underwent endovascular coil embolizations on the day or the next day of the onset. Subsequent rupture occurred in 4 patients before embolization. The Glasgow Outcome Scale at 3 months after the embolization was good recovery in 3 patients. We had no ruptured aneurysm and no coil compaction at 0 to 40 months (mean 26.2 months) after embolization. Our experience showed that the internal trapping for ruptured dissecting aneurysms of the vertebral artery should be performed as soon as possible, even if the patients have a Hunt and Kosnik Grade of V.

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De novo development of moyamoya disease in an adult female

Fukaya, Raita, Yoshida, Kazunari, Akiyama, Takenori, Kawase, Takeshi

JOURNAL OF NEUROSURGERY (AMER ASSOC NEUROLOGICAL SURGEONS) 111 ( 5 ) 943 - 946 2009.11

Research paper (scientific journal), Joint Work, ISSN 0022-3085

The origin of moyamoya disease remains unknown. The onset of the angiographically apparent changes of typical moyamoya disease occurs in childhood, but de novo development of the disease has not been confirmed angiographically. The authors report on a case of de novo development of moyamoya disease in a middle-aged female whose cerebral angiography demonstrated no abnormal findings 5 years previously. To the best of the authors' knowledge, this case is the first reported instance of de novo development of definite moyamoya disease verified angiographically. This case demonstrates that the de novo development of moyamoya disease in a middle-aged adult did in fact occur, and angiographically visible features of the disease took < 5 years to complete. (DOI: 10.3171/2009.2.JNS081244)

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頸動脈stent留置術における狭窄部通過困難例に対する工夫 0.035 inch guidewireを用いて

植田良, 赤路和則, 秋山武紀, 谷崎義生, 傳法倫久, 篠田純, 小嶋篤浩, 片山正輝, 菅貞郎, 中村芳樹

JNET: Journal of Neuroendovascular Therapy ((NPO)日本脳神経血管内治療学会) 3 ( 4 ) 310 - 310 2009.11

ISSN 1882-4072

The Possibility of Left Dominant Activation of the Sensorimotor Cortex During Lip Protrusion in Men

Fukunaga, Atsushi, Ohira, Takayuki, Kamba, Masayuki, Ogawa, Seiji, Akiyama, Takenori, Kawase, Takeshi

BRAIN TOPOGRAPHY (SPRINGER) 22 ( 2 ) 109 - 118 2009.09

Research paper (scientific journal), Joint Work, ISSN 0896-0267

Lip protrusion requires bilateral symmetrical movements of the facial muscles, but the laterality of the activated sensorimotor cortex corresponding to the area of the face activated during lip protrusion remains under discussion. In this study, blood-oxygenation-level-dependent (BOLD) responses in the sensorimotor cortex during non-verbal lip protrusion were evaluated in a 3T magnetic field in twenty healthy right-handed subjects. The results showed that the activated sensorimotor area on the left side was larger than that on the right side, and there was a statistically significant difference in the number of activated voxels between the left and right sensorimotor cortex in an individual study of the male group, although approximately symmetrical motor action potentials of facial muscles were recorded during lip protrusion. There was a statistically significant difference in interaction between the hemisphere (right and left) and sex (men and women) and multiple comparison test showed statistical significant differences between "men and right" and "men and left", and between "men and left" and "women and left". The peak value of the percent changes in BOLD signal responses on the left side was approximately twice as high as that on the right side in the males of the group, though the bilateral sensorimotor cortex was almost equally activated in the females in the group. In addition, the left primary sensory area related to the face area was significantly activated as a region where Male was more active than Female in a general linear model (multi-study, multisubject) analysis. This study revealed the possibility that the left sensorimotor cortex was more closely involved in non-verbal mouth movement in men, suggesting sex-related differences in sensorimotor cortex activation.

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頸動脈stent留置術における末梢塞栓保護用deviceの選択 Balloon protectionとReversal flow systemとの併用法の有用性

赤路和則, 秋山武紀, 平賀健司, 谷崎義生, 傳法倫久, 篠田純, 小嶋篤浩, 片山正輝, 菅貞郎, 中村芳樹

JNET: Journal of Neuroendovascular Therapy ((NPO)日本脳神経血管内治療学会) 2 ( 4 ) 161 - 161 2008.11

ISSN 1882-4072

Source analysis of the magnetic field evoked during self-paced finger movements

Niimi, Maki, Ohira, Takayuki, Akiyama, Takenori, Hiraga, Kenji, Kaneko, Yousei, Ochiai, Masato, Fukunaga, Atsushi, Kobayashi, Masahito, Kawase, Takeshi

NEUROLOGICAL RESEARCH (MANEY PUBLISHING) 30 ( 3 ) 239 - 243 2008.04

Research paper (scientific journal), Joint Work, ISSN 0161-6412

Objective: The aim of this study is to investigate a source of cortical magnetic fields evoked by index finger movements.
Methods: We analysed both movement-related cortical fields (MRCFs) and somatosensory-evoked fields (SEFs) by single equivalent current dipole (ECD) method in six healthy subjects. Dipole locations were superimposed on MR images of each individual subject.
Results: The first component after finger movement (movement-evoked field I, MEFI) was observed in all subjects. The dipole of MEFI was oriented posteriorly, and was located on the posterior wall of the central sulcus of the hemisphere contralateral to the movement. The SEFs showed three major components: N20m, P30m and P60m. The dipoles of P30m and P60m were orientated posteriorly, similarly to the MEFI dipole, while that of N20m was orientated anteriorly. The dipole location of MEFI was closely located to P60m, not to N20m and P30m. The mean location of the MEFI dipole was significantly (p < 0.05) superior to N20m.
Conclusion: These findings suggest that MEFI would be generated in the sensory area ( area 3b) affected by multiple afferents and activities, and that the source of the MEFI is not identical to that of the N20m component.

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Hemodynamic response following neuronal activity in cases with severe stenosis of the cervical internal carotid artery and its serial change through carotid artery stenting

AKIYAMA Takenori, OHIRA Takayuki, HIRAGA Kenji, TANIZAKI Yoshio, AKAJI Kazunori, KAWASE Takeshi

Journal of Neuroendovascular Therapy (The Japanese Society for Neuroendovascular Therapy) 2 ( 2 ) 93 - 100 2008

ISSN 1882-4072

Objective: Regional cerebral blood flow (CBF) increasing focally at sites of neural activity is called "hemodynamic response (HDR)". In cases with severe cerebral ischemia, HDR may be disturbed and cause disruption of normal neuro-vascular coupling. HDR was measured during a motor task using functional near infrared spectroscopy (fNIRS) in cases with severe cervical internal carotid artery (ICA) stenosis before and after carotid artery stenting (CAS). Ischemia and the influence of therapy for it on HDR was analyzed.Methods: Seventeen right-handed patients with severe cervical ICA stenosis admitted for CAS were examined. fNIRS during a motor task was performed and concentration changes in oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (HbR), and total hemoglobin (tHb) were calculated in these patients in addition to routine evaluations. The same measurements were repeated after CAS and serial data were evaluated. In order to analyze the relevance of HDR to CBF status, Xenon-enhanced computed tomography (Xe-CT) was performed before and after CAS.Results: Some abnormalities in the HDR curve and its recovery after CAS were detected, including a delay in peak time of tHb concentration, of more than 10 seconds during the 20 second stimulation, in 9 cases. TTP0.7 (time to peak) value, defined as the time to reach seventy percent of maximum tHb concentration, was observed to be higher in patients with low CBF at rest before CAS. In the group with a high TTP0.7 value, CBF at rest before CAS was lower than 35mL/100g/min., significantly lower than the group without a high TTP0.7 value (P<0.01). Additionally, in the group with a high TTP0.7 value, CBF increase after CAS was significantly higher than the group with a lower TTP0.7 value (P<0.01).Conclusions: In some cases with severe ICA stenosis, cortical hemodynamics, and oxygen metabolism during functional activation are disturbed, and CAS can modulate these changes. This result is important in that intervention for cervical IC stenosis can not only reduce ischemic events, but also influence cortical hemodynamics during functional activity.

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近赤外線トポグラフィーによる大脳皮質顔面一次運動野描出の試みと問題点

'AKIYAMA TAKENORI, Ohira Takayuki, Hiraga Kenji, Niimi Maki, Fukunaga Atsushi, Kawase Takeshi, Kato Toshinori'

Facial nerve research (日本顔面神経研究会) 23 51-53 2003.12

Research paper (scientific journal), Single Work

Spontaneous resolution of nontraumatic bilateral intracranial vertebral artery dissections―case report―

Fukunaga Atsushi, Tabuse Masanao, Naritaka Heiji, Nakamura Tsuneo, Akiyama Takenori

Neurol Med Chir (Tokyo) (JAPAN NEUROSURGICAL SOC) 42 ( 11 ) 491-495 - 495 2002.11

Research paper (scientific journal), Joint Work, ISSN 0470-8105

A 49-year-old man presented with nontraumatic bilateral intracranial vertebral artery dissections without subarachnoid hemorrhage manifesting as Wallenberg's syndrome on the right. Magnetic resonance imaging revealed an infarct in the right dorsolateral aspect of the medulla oblongata. Antiplatelet therapy was administered. Vertebral angiography performed on the 9th hospital day (Day 9) revealed pearl and string sign in the right vertebral artery and narrowing of the left vertebral artery. Second angiography performed on Day 25 showed no change, but third angiography performed on Day 74 revealed spontaneous resolution of the bilateral vertebral artery dissections. Magnetic resonance angiography performed on Day 250 showed no evidence of dissection. However, magnetic resonance imaging revealed a small infarct in the splenium of the corpus callosum. Spontaneous resolution of stenotic dissections of the bilateral vertebral arteries is extremely unusual. Serial cerebral angiography and magnetic resonance angiography are very important for monitoring the time course of changes in patients with vertebral artery dissections.

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