Akiyama, Takenori



School of Medicine, Department of Neurosurgery (Shinanomachi)


Assistant Professor/Senior Assistant Professor

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Academic Background 【 Display / hide

  • 1998.03

    Keio University, Faculty of Medicine

    University, Graduated

Academic Degrees 【 Display / hide

  • 博士(医学), Keio University, Dissertation, 2008.09


Research Areas 【 Display / hide

  • Neurosurgery (Cerebral Neurosurgery)

Research Keywords 【 Display / hide

  • functional neurosurgery

  • interventional neuroradiology

  • cerebrovascular disease


Papers 【 Display / hide

  • 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

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    © 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.

  • 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

    ISSN  18788750

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    © 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.

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

    Mizutani K., Arai N., Toda M., Akiyama T., Fujiwara H., Jinzaki M., Yoshida K.

    World Neurosurgery (World Neurosurgery)  131   e176 - e185 2019.11

    ISSN  18788750

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    © 2019 Elsevier Inc. 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.

  • 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

    ISSN  18788750

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    © 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.

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

    Arai N., Horiguchi T., Takahashi S., Nakahara T., Akiyama T., Jinzaki M., Yoshida K.

    Neurosurgical Review (Neurosurgical Review)   2019

    ISSN  03445607

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    © 2019, Springer-Verlag GmbH Germany, part of Springer Nature. 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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Papers, etc., Registered in KOARA 【 Display / hide

Presentations 【 Display / hide

  • 慢性閉塞性脳血管病変の治療前後における機能活動時の大脳皮質酸素代謝-多チャンネルfNIRSを用いた検討-

    'AKIYAMA TAKENORI, Ohira Takayuki, Kawase Takeshi, Kato Toshinori'

    第15回日本脳循環代謝学会総会 (大阪) , 2003.10, Poster (general)

  • 脳虚血疾患で運動負荷によって引き起こされた一次運動野の低酸素賦活反応—機能的NIRSを用いた検討—

    'AKIYAMA TAKENORI, Ohira Takayuki, Fukunaga Atsushi, Kawase Takeshi, Kato Toshinori'

    第33回日本臨床神経生理学会・学術大会 (旭川) , 2003.10, Poster (general)

  • 視床下核へのDBS電極留置術後に一過性にdyskinesiaが消失したParkinson病の一例

    'AKIYAMA TAKENORI, Ohira Takayuki, Hiraga Kenji, Ochiai Masato, Kawase Takeshi'

    第42回日本定位・機能神経外科学会 (仙台) , 2003.09, Oral Presentation(general)

  • Analysis of Hb concentration change detected by TMS mapping oriented NIRS in the activated cerebral cortex during motor task

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

    Human Brain Mapping 2003 ('New York, USA') , 2003.06, Poster (general)

  • 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


    第26回日本顔面神経研究会 (東京) , 2003.06, Oral Presentation(general)

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Courses Taught 【 Display / hide