| Project/Area Number |
15390515
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Otorhinolaryngology
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| Research Institution | Nagoya University |
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Principal Investigator |
NAKASHIMA Tsutomu Nagoya University, Graduate School of Medicine, Professor, 大学院・医学系研究科, 教授 (30180277)
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| Co-Investigator(Kenkyū-buntansha) |
FUJII Hitoshi Kyushu institute of Technology, Computer science and systems engineering, Professor, 情報工学部, 教授 (70133775)
SONE Michihiko Nagoya University, Graduate School of Medicine, Associate Professor, 大学院・医学系研究科, 助教授 (30273238)
TERANISHI Masaaki Nagoya University, University Hospital, Research Associate, 医学部附属病院, 助手 (20335037)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥12,300,000 (Direct Cost: ¥12,300,000)
Fiscal Year 2005: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2004: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2003: ¥9,900,000 (Direct Cost: ¥9,900,000)
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| Keywords | Cochlea / Blood flow / Laser / Speckle / Schwartze sign / Otosclerosis / Venous congestion / 内耳 / レーザースペックル / レーザードップラー / レーザースッペクル / 感音難聴 |
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| Research Abstract |
The cochlea is principally supplied from the inner ear artery (labyrinthine artery), which is usually a branch of the anterior inferior cerebellar artery (AICA). The human cochlea is not easily accessible for investigation because this delicate sensory organ is hidden deep in the temporal bone. However, we could measure cochlear blood flow (CBF) in patients who received cochlear implants, using a laser-Doppler probe placed over the site of drilling in the cochlear bony wall. In the patients with idiopathic progressive sensorineural hearing loss, the CBF was significantly lower in patients more than 40 years old. Intracochlear calcification following meningitis also appeared to be associated with a reduced CBF.
Using lase-speckle flowgraphy, pulsation of the AICA was observed in rats, but evaluation of the CBF itself was very difficult. However, in patients with cochlear otosclerosis, blood flow to the promontory was evaluated using the laser-speckle flowgraphy. It has been reported that vascular shunts exist between the cochlea and the surrounding bone in cochlear otosclerosis. Some authors speculated that these vascular shunts might represent collateral circulation from the membraneous cochlea, which bypasses the reduced or absent capillary networks of the spiral ligament and drains into the vessels of the otosclerotic focus. In our study, patients with otosclerosis exhibited elevated and pulsating blood flow to the promontory with the Schwartze sign. The Schwartze sign correlated significantly with otosclerotic lesions invading the promontory. It is possible that blood flow inside the cochlea decreases due to the venous congestion in cochlear otosclerosis. If so, blood flow differs between the inside and outside of the cochlea in cochlear otosclerosis
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