Publications by authors named "Masahiro Yonekura"

Objective: To build a prediction model that estimates the 3-year rupture risk of unruptured saccular cerebral aneurysms.

Methods: Survival analysis was done using each aneurysm as the unit for analysis. Derivation data were from the Unruptured Cerebral Aneurysm Study (UCAS) in Japan.

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Background: The decision of whether to treat incidental intracranial saccular aneurysms is complicated by limitations in current knowledge of their natural history. We combined individual patient data from prospective cohort studies to determine predictors of aneurysm rupture and to construct a risk prediction chart to estimate 5-year aneurysm rupture risk by risk factor status.

Methods: We did a systematic review and pooled analysis of individual patient data from 8382 participants in six prospective cohort studies with subarachnoid haemorrhage as outcome.

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We recently encountered experienced a rare case of transient pupil-sparing oculomotor nerve palsy(PSONP)caused by an aneurysm at the junction of the internal carotid-and posterior communicating arteries(IC/PC AN)in an 87-year-old, non-diabetic woman. She initially presented with diplopia 4 years previously, and was diagnosed, based on incomplete right oculomotor paresis without pupil involvement(PSONP), as external ophthalmoplegia. MR-angiography revealed a long protrusion of the IC/PC AN with posterior-inferior projection, for which she chose to receive conservative management.

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Polyarteritis nodosa (PAN) is a rare, systemic necrotizing vasculitis of small and medium size arteries that leads to aneurysms in various organs. Aneurysms associated with PAN are common in visceral arteries, however, intracranial aneurysms are rare, especially in childhood. A pediatric patient with PAN developed serial hemorrhagic strokes from a ruptured superior cerebellar artery aneurysm (subarachnoid hemorrhage) and a de novo aneurysm of the frontoorbital artery (intracerebral hemorrhage) after 9 months.

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We recently encountered a rare case of anterior cerebral artery dissection (ACAD) that accompanied fresh cerebral infarction (CI) and subarachnoid hemorrhage (SAH). An initial head CT showed a thin SAH in the interhemispheric cistern and cortical sulcus of the left frontal surface. Subsequent MRI performed 10 min after head CT scan revealed a fresh infarction in the left ACA region.

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A 61-year-old woman presented with dementia, 7 years after an operation for retroperitoneal leiomyosarcoma. Magnetic resonance imaging (MRI) revealed enhanced masses with perifocal edema in the bilateral frontal regions and a very small mass in the right medial frontal region. The tumors in the bilateral frontal regions were completely removed surgically, and γ-knife radiotherapy was administered for the very small tumor in the right medial frontal region.

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A 61-year-old man with a history of cerebellar infarction was transferred to our hospital for the treatment of vertebral artery (VA) stenosis. The VA dissection was treated with endovascular stent placement followed by coil embolization in which shrinkage of the dissecting aneurysm was confirmed by the three-dimensional driven equilibrium (3D DRIVE) sequence. Using 3D DRIVE, the outer contour of the aneurysm was well visualized, free from the influence of the metallic devices.

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Dolichoectasia of the intracranial arteries is a rare condition, and the vertebrobasilar system and the internal carotid artery are the most commonly involved structures. We report a rare case of idiopathic dolichoectasia of the anterior cerebral artery in a 22-year-old female. The patient caused an automobile accident and was brought to our hospital in an ambulance.

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Hypertensive intracerebral hemorrhage (HICH) causes significant morbidity and mortality. The time required to transport the patients to a specialized hospital can influence the prognosis. In the isolated islands in Nagasaki prefecture, there is no medical institution which can offer emergent neurosurgical intervention.

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An 86-year-old woman presented with a 10-year history of right paroxysmal facial pain. The trigger zone was the right maxilla. Magnetic resonance (MR) angiography and MR cisternography sourse images showed an aberrant artery originating from the right internal carotid artery anastomosed to the anterior inferior cerebellar artery territory (AICA) of the cerebellum, and it was closed at the root entry zone of trigeminal nerve.

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Background: Stroke is a major cause of dysphagia, but little is known about when and how dysphagic patients should be fed and treated after an acute stroke. The purpose of this study is to establish the feasibility, risks and clinical outcomes of early intensive oral care and a new speech and language therapist/nurse led structured policy for oral feeding in patients with an acute intracerebral hemorrhage (ICH).

Methods: A total of 219 patients with spontaneous ICH who were admitted to our institution from 2004 to 2007 were retrospectively analyzed.

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Background And Purpose: The natural history and optimal management of incidentally found small unruptured aneurysms <5 mm in size remain unclear. A prospective study was conducted to determine the optimal management for incidentally found small unruptured aneurysms.

Methods: From September 2000 to January, 2004, 540 aneurysms (446 patients) were registered.

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A 77-year-old man presented with progressive visual disturbance. MR images revealed a mass lesion mainly spreading in the left basal cistern, sylvian fissure and to the left hypothalamic region, with ventricular enlargement. To obtain precise diagnosis of the mass lesion, an open biopsy was performed.

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A 28-year-old female presented with a dermoid tumor in the posterior fossa associated with symptomatic syringomyelia. Magnetic resonance (MR) imaging revealed cervical syringomyelia and tonsillar herniation concomitant with an intradural posterior fossa tumor which was totally removed. The histological diagnosis was dermoid tumor.

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A 17-year-old female with Chiari 2 malformation developed cerebral infarction with angiographically typical bilateral moyamoya vessels manifesting as sudden onset of moderate left hemiparesis. Magnetic resonance imaging revealed multiple infarcts in the right frontal lobe, agenesis of the corpus callosum, upward herniation of the dorsal cerebellum, tectal beak of the midbrain, and downward herniation of the cerebellar vermis. Cerebral angiography demonstrated occlusion of the bilateral internal carotid arteries and basal moyamoya vessels.

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Background And Purpose: Several unruptured cerebral aneurysms have been reported to grow and rupture. To determine which factors affect the growth of these aneurysms during the acute stage of subarachnoid hemorrhage (SAH), a retrospective review was performed.

Methods: Between January 2000 and January 2003, 130 patients with angiographically proven ruptured cerebral aneurysms were treated at our institution.

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A 1-year-old male infant presented with a rare cerebral composite tumor consisting of atypical teratoid/rhabdoid tumor (AT/RT) with epithelial and mesenchymal components and yolk sac tumor (YST) with Schiller-Duval bodies. He was admitted to our medical center with a 2-month history of right hemiparesis. Computed tomography and magnetic resonance imaging revealed a large, intra-axial solid tumor with a cyst in the left frontal lobe.

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A prospective study (SUAVe Study, Japan) is in progress at 13 national hospitals to determine the surgical indications for small unruptured intracranial aneurysm. These hospitals are observing the natural history of small unruptured aneurysms (under 5 mm diameter) without surgical treatment. Since October 2000, 455 aneurysms (393 patients) with 75 aneurysms excluded by film judgment committees have been registered, of which 380 aneurysms (329 cases) have been followed up for a mean of 13.

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A series of 10 cases of posterior cerebral artery (PCA) aneurysms were retrospectively reviewed. There were five men and five women aged 38 to 68 years (mean 57.5 years).

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Endovascular treatment for a spontaneous dural carotid-cavernous fistula (CCF) is an established treatment, but stereotactic radiosurgery might provide a less-invasive alternative in selected cases. Four women aged 67 to 79 years (mean 72.0 years) with spontaneous dural CCFs presented with chemosis or bruit.

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Background: Congenital cavernous angioma is a very rare tumor that occurs in young adolescents. We describe a rare case of congenital cavernous angioma of the temporal bone in a neonate. Ultrasonography (US) and dynamic magnetic resonance imaging (MRI) were helpful in its diagnosis.

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Background And Purpose: Proportions of patients with single and multiple aneurysms among patients suffering from subarachnoid hemorrhage (SAH) are not well established. We evaluated these proportions and the differences in outcome between SAH patients with a single aneurysm and those with multiple aneurysms in a defined population.

Methods: Between 1989 and 1998, 2037 patients (age, 20 to 89 years) with ruptured intracranial aneurysm were treated in 11 hospitals in Nagasaki Prefecture.

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