Faculty Profiles - NAGANAWA, Shinji

Papers - NAGANAWA, Shinji

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Sudden sensorineural hearing loss associated with inner ear anomaly. Reviewed

Sugiura M, Nakashima T, Naganawa S, Otake Y, Mukaida T, Sone M, Sato E

Otol Neurotol Vol. 26 ( 2 ) page： 241-246 2005

Language：English Publishing type：Research paper (scientific journal)

OBJECTIVE: This study was conducted to evaluate the frequency of inner ear anomaly in patients with sudden sensorineural hearing loss and in control subjects. STUDY DESIGN: Retrospective case review. SETTING: A tertiary referral center. PATIENTS AND INTERVENTION: We evaluated 366 patients (165 men and 201 women; age range, 3-91 yr) with sudden sensorineural hearing loss and 228 control subjects without sensorineural hearing loss using magnetic resonance imaging. Three hundred fifty-six patients had unilateral and 10 patients had bilateral sudden sensorineural hearing loss. RESULTS: Eleven (2.9%) of 376 ears with sudden sensorineural hearing loss had inner ear anomaly. Nine patients (2.5%) had inner ear anomaly associated with sudden sensorineural hearing loss, but none of the 228 control subjects had the anomaly. The current study demonstrated that the frequency of inner ear anomaly in patients with sudden sensorineural hearing loss was significantly higher than in control subjects. CONCLUSION: Our study reveals that inner ear anomaly may be associated with sudden sensorineural hearing loss in 2.5% of patients.

DOI： 10.1097/00129492-200503000-00019

Diffusion-weighted images of the liver: comparison of tumor detection before and after contrast enhancement with superparamagnetic iron oxide.

Naganawa S, Sato C, Nakamura T, Kumada H, Ishigaki T, Miura S, Maruyama K, Takizawa O

J Magn Reson Imaging Vol. 21 ( 6 ) page： 836-840 2005

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

PURPOSE: To study the recognition of malignant lesions of the liver on diffusion-weighted images (DWI) can be improved by the administration of superparamagnetic iron oxide (SPIO). MATERIALS AND METHODS: Pre- and post-SPIO mediated DWI of the liver was compared in six patients with suspected malignant liver lesions at 1.5 Tesla using a parallel imaging technique. RESULTS: Post-SPIO DWI showed improved contrast-to-noise ratio between malignant lesions and liver. Furthermore, the spleen signal was decreased on post-SPIO DWI, thus avoiding the overlap of the spleen and left lobe of the liver on maximum intensity projections (MIP). CONCLUSION: Recognition of malignant lesions of the liver was improved by SPIO on DWI. On MIP images of DWI, SPIO helped to decrease the overlap of spleen signal on the liver in some projection angles.

DOI： 10.1002/jmri.20346

Hearing loss in patients with enlarged vestibular aqueduct: air-bone gap and audiological Bing test. Reviewed

Mimura T, Sato E, Sugiura M, Yoshino T, Naganawa S, Nakashima T

Int J Audiol Vol. 44 ( 8 ) page： 466-469 2005

Language：English Publishing type：Research paper (scientific journal)

The Bing test is based on the principle that occlusion of the external auditory meatus improves the perception of bone-conducted sounds unless there is a conductive hearing impairment. An air-bone gap has been reported in patients with large vestibular aqueduct (LVA) syndrome without apparent middle ear dysfunction. We therefore performed the Bing test on nine patients with this syndrome to evaluate whether it is associated with an air-bone gap or middle ear dysfunction. Bone conduction thresholds did not change significantly during the Bing test in any patient. Because an air-bone gap is observed in patients with abnormal communication between the inner ear and cerebrospinal fluid through the LVA, dehiscent superior canal, or dilated inner ear meatus; we propose that a 'three windows' model (in which the abnormal communication provided by the enlarged endolymphatic duct and sac in LVA acts as the 'third window' for sound conductance) might explain the air-bone gap in such patients.

DOI： 10.1080/14992020500057665

【最近の画像診断の進歩　CT,MRI,PET】　高磁場MRI

長縄慎二

日本医師会雑誌 Vol. 134 page： 1722-1726 2005

多系統萎縮症における認知機能障害　画像との関連

川合圭成, 伊藤瑞規, 渡邉宏久, 祖父江元, 武田章敬, 長縄慎二, 深津博, 加藤克彦, 石垣武男

臨床神経学 Vol. 45 page： 1185 2005

第３３回日本磁気共鳴医学会大会にみるBody diffusionの動向

長縄慎二

Innervision Vol. 20 ( 12 ) page： 112 2005

高磁場MRI

長縄慎二

日本医師会雑誌 Vol. 134 ( 9 ) page： 1722-1726 2005

超高磁場MRIのインパクト(3T MRIをふくめて）脳以外への活用方法

長縄慎二

日独医報 Vol. 50 ( 3 ) page： 479-489 2005

前立腺癌，子宮頸癌におけるADC測定の意義

長縄慎二

画像診断 Vol. 25 ( 6 ) page： 737-743 2005

Authorship：Lead author Language：Japanese

DWIBSにおいての癌描出のメカニズムは十分に把握されておらず，基礎的な検討としても，現時点での臨床的な課題としても，さまざまな種類の癌のADCを測定することが重要である．前立腺癌と子宮頸癌におけるADC計測の結果と臨床的な位置付けを1.5T，3Tでの結果に基づいて解説する

電子ポスター(Cypos)元年　JRC2005を振り返って

石垣武男　藤田広志　深津博　長縄慎二　片渕哲朗　原武史

Innervision Vol. 20 ( 7 ) page： 28-33 2005

第64回日本医学放射線学会学術集会　イメージインタープリテーションセッション症例出題集

長縄慎二、原真咲

日本医学放射線学会誌別冊付録 Vol. 65 ( 3 ) page： 1-28 2005

第64回日本医学放射線学会学術集会　イメージインタープリテーションセッション症例出題集

長縄慎二、原真咲

日本医学放射線学会誌別冊付録 Vol. 65 ( 2 ) page： 1-14 2005

【医療環境の変化に対して放射線診療は今後どう対応すべきか　画像診断を中心に】　高度画像診断機器導入による画像診断へのインパクト　医療制度の変化を踏まえて　超高磁場MRIのインパクト(3T MRIを含めて)　脳以外への活用方法

長縄慎二

日独医報 Vol. 50 page： 479-489 2005

多発性硬化症におけるIsotropic 3D FLAIR法の有用性

末永正機, 伊藤瑞規, 熱田直樹, 渡邉宏久, 祖父江元, 深津博, 長縄慎二

臨床神経学 Vol. 45 page： 1035 2005

多系統萎縮症とパーキンソン病の鑑別　橋の拡散テンソル画像,拡散強調画像の有用性

伊藤瑞規, 熱田直樹, 川合圭成, 渡邉宏久, 祖父江元, 長縄慎二, 深津博, 石垣武男

臨床神経学 Vol. 45 page： 1168 2005

Serial evaluation of diffusion tensor brain fiber tracking in a patient with severe diffuse axonal injury. Reviewed

Naganawa S, Sato C, Ishihra S, Kumada H, Ishigaki T, Miura S, Watanabe M, Maruyama K, Takizawa O

AJNR Am J Neuroradiol Vol. 25 ( 9 ) page： 1553-1556 2004.10

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Serial evaluation of diffusion tensor brain fiber tracking was performed in a 27-year-old female patient with diffuse axonal injury after a traffic accident. Although the result of brain fiber tracking was not necessarily parallel to her clinical symptoms, it may have predicted the neurologic prognosis.

Rad Talk ISMRM2004

長縄慎二

Rad Fan Vol. 2 ( 6 ) page： 47-56 2004.10

High-speed imaging at 3 Tesla: a technical and clinical review with an emphasis on whole-brain 3D imaging. Reviewed

Naganawa S, Kawai H, Fukatsu H, Ishigaki T, Komada T, Maruyama K, Takizawa O

Magn Reson Med Sci Vol. 3 ( 4 ) page： 177-187 2004

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Improvements to the inherently high specific-absorption rate (SAR) of high-speed imaging at 3T are necessary in order to render this method clinically feasible. Various efforts have been undertaken to improve the associated hardware and software. In this review, we focus on whole-brain isotropic 3D imaging with a turbo spin-echo sequence with variable flip-angle echo trains (3D-TSE-VFL) and present its technical and clinical features. This sequence can be used to acquire images of various contrasts including T2-weighted, fat-suppressed T2-weighted, fluid-attenuated inversion recovery (FLAIR), fat-suppressed FLAIR, and STIR (short tau inversion recovery). Various aspects of 3D-TSE-VFL are discussed, including CSF (cerebrospinal fluid) and metal artifacts, STIR contrast, small-part visualization other than brain, and the possibility of serial subtraction. Some images from clinical cases are presented.

Flow ghost artifact in slice-encoding direction mimicking vestibular schwannoma in contrast-enhanced 3D spoiled gradient-echo sequence. Reviewed

Naganawa S, Koshikawa T, Fukatsu H, Ishigaki T, Aoki I

Eur Radiol Vol. 14 ( 3 ) page： 496-499 2004

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

The value of MR imaging by post-contrast T1-weighted 3D spoiled gradient-echo (3D SPGR) is well established for the detection of small vestibular schwannomas in the cerebellopontine angle region. We describe a case in which a flow ghost artifact in the slice-encoding direction mimicked a vestibular schwannoma and heavily T2-weighted MR cisternography and multiplanar reconstruction images helped us to reach the correct diagnosis. In addition, we conducted a volunteer study to demonstrate that changing the k-space trajectory can reduce this artifact in post-contrast 3D SPGR images.

DOI： 10.1007/s00330-003-2113-3

Pre-surgical mapping of primary motor cortex by functional MRI at 3 T: effects of intravenous administration of Gd-DTPA. Reviewed

Naganawa S, Nihashi T, Fukatsu H, Ishigaki T, Aoki I

Eur Radiol Vol. 14 ( 1 ) page： 112-114 2004

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

The functional magnetic resonance imaging (fMRI) is often performed at the end of a routine MRI examination during which, dependent on the clinical indication, contrast agent has been administered; however, the effects of Gd-DTPA injection on the results of blood oxygenation level dependent (BOLD)-fMRI remain unknown. The present study was conducted to investigate the effects of the intravenous administration of Gd-DTPA on the results of pre-surgical localization of the primary motor cortex by BOLD-fMRI at 3 T. Eight normal subjects were included in this study. After the anatomical scans, pre- and post-contrast fMRI scanning was performed. The number of significantly activated voxels and the mean percentage signal change were compared. The mean number of significantly activated voxels was 115.0+/-27.0 in pre-contrast runs and 90.8+/-27.1 in post-contrast runs (mean value of all 8 volunteers+/-standard deviation; p<0.05). The mean mean percentage signal change was 4.07+/-0.39 in pre-contrast runs and 3.86+/-1.91 in post-contrast runs ( p=0.16). Pre-surgical localization of the motor area by BOLD-fMRI should be performed before the administration of Gd contrast material.

DOI： 10.1007/s00330-003-2147-6

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Papers - NAGANAWA, Shinji