Japanese

Title	必見! 画像でわかる神経眼科疾患
Subtitle	第61回 日本視能矯正学会 特別講演
Authors	橋本雅人
Authors (kana)
Organization	医仁会 中村記念病院眼科
Journal	日本視能訓練士協会誌
Volume	50
Number
Page	1-11
Year/Month	2021 /
Article	報告
Publisher	日本視能訓練士協会
Abstract	「要約」神経眼科疾患におけるMRI検査の着目点, 画像診断の方法, 読影について解説した. 眼窩部画像診断において, 球後視神経の評価には脂肪抑制法の一つであるSTIR法と造影MRIの冠状断撮影が最も有用な方法である. 視神経炎では, STIR法で視神経全体が高信号および造影T1強調画像で造影効果を示すのに対し, 虚血性視神経症やレーベル遺伝性視神経症では正常視神経と変わらない画像となる. また外眼筋肥大を示す疾患としては, 甲状腺眼症, 眼窩筋炎, IgG4関連眼疾患, 筋への転移性腫瘍が代表的であり, 各々特徴的な画像を示す. 頭部画像診断において, 眼球運動障害特に動眼, 滑車, 外転神経麻痺については高速グラジエントフィールドエコー法であるSPGRとFIESTA-C (GE社製の呼称) が有用である. SPGRはMR angiographyの元画像で動脈血が高信号であらわされる特徴があるため, 脳動脈瘤, 頸動脈海綿静脈洞瘻 (CCF) の診断に最も有用な手法である. また, FIESTA-Cは, 髄液中にある微細構造物を描出するのに長けているため, 脳幹を出た脳神経の描出にはFIESTA-Cが有用な方法である. また, 2つのMRI (主にFIESTA-CとMRA) を一つの画像に融合させ3Dで表現したフュージョン3D画像は, 片側顔面痙攣や上斜筋ミオキミアといった顔面神経, 滑車神経の血管圧迫性脳神経症の診断にも有用である.
Practice	医療技術
Keywords

English

Title	Diagnostic imaging for Neuro-ophthalmologic disorders
Subtitle
Authors	Masato Hashimoto
Authors (kana)
Organization	Department of Ophthalmology, Nakamura Memorial Hospital
Journal	Japanese Orthoptic Journal
Volume	50
Number
Page	1-11
Year/Month	2021 /
Article	Report
Publisher	Japanese Association of Certified Orthoptists
Abstract	[Abstract] We describe the usefulness of magnetic resonance imaging (MRI) for diagnosis of neuro-ophthalmological diseases. It is important to focus the lesion responsible for the clinical neuro-ophthalmologic features. Anatomically. the retrobulbar optic nerve is surrounded by pia matter, subarachnoid and dura matter (optic nerve sheath). These anatomical structures are most markedly demonstrated by short tau inversion recovery (STIR) imaging. which is one of the fat-suppressed methods, because the STIR suppresses the signal of intraorbital fat. Moreover, STIR shows slow flow of water such as the cerebral spinal flow (CSF), inflammatory edema as high signal image. Therefore, the combination of STIR and post contrast MRI can demonstrate the characteristics of acute optic nerve disorders such as optic neuritis, optic perineuritis and ischemic optic neuropathy (ION). Optic neuritis shows high signal intensity on STIR and post-contrast enhancement, while ION and Leber's hereditary optic neuropathy have not high signal intensity on STIR without enhancement. Orbital diseases with extraocular muscle hypertrophy including thyroid-associated ophthalmopathy, IgG4-related ophthalmic disease, orbital myositis and metastatic orbital tumor have characteristic findings on orbital MRI respectively. On brain MRI of the middle fossa, the coronal image is the most important plane to evaluate for pituitary or cavernous sinus lesions because the angle of the coronal plane can demonstrate the anatomically positional relationship between the chiasm and the lesion. High resolution gradient field echo sequences such as spoiled gradient steady-state recalled acquisition (SPGR) and fast imaging employing steady-state acquisition (FIESTA-C) imaging, providing high spatial resolution, are very useful for oculomotor disorders. SPGR, which is a source of MR angiography (MRA), has a characteristic image that arterial blood flow is demonstrated by high signal intensity, Therefore, it is very useful for detecting cerebral aneurysm or carotid cavernous sinus fistulas. FIESTA-C has successfully visualized small cranial nerves : oculomotor, trochlear, abducens and facial nerves. This sequence in combination with MR angiography, so-called fusion 3-D image can demonstrate a very tiny cranial nerve lesion such as neurovascular compression syndrome which has never been clearly delineated on MRI.
Practice	Medical technology
Keywords

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