Publications by authors named "Hideaki Imai"

Article Synopsis
  • The study investigates periventricular anastomosis (PA) aneurysms in Moyamoya disease (MMD), revealing that these aneurysms are rare but can significantly impact patient outcomes.* -
  • Results show that having a PA aneurysm correlates with higher initial disability scores (mRS) and a higher likelihood of future hemorrhagic strokes, indicating it as a risk factor for adverse events.* -
  • Advanced analysis techniques, like machine learning and principal component analysis, underscore the unique characteristics of hemorrhagic-onset aneurysms, suggesting that greater PA development increases the risk of aneurysm presence and complications.*
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Article Synopsis
  • Intracranial artery stenosis (ICAS) is linked to ischemic stroke, and the RNF213 p.Arg4810Lys genetic variant may play a role in this condition, particularly in patients who are asymptomatic.
  • A study involving 139 patients showed that 25% carried the RNF213 variant, which was associated with higher rates of stenosis progression (25.7%) compared to non-carriers (8.7%) over an average follow-up of 58 months.
  • The findings indicate that the RNF213 p.Arg4810Lys variant is significantly associated with increased risk of stenosis progression, suggesting different underlying mechanisms in vascular health that merit further research.
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Objective: The genetic basis underlying the pathophysiology of quasi-moyamoya disease (qMMD) is unclear. Herein, the authors aimed to comprehensively analyze genetic variants in qMMD and investigate their association with clinical phenotypes, focusing on RNF213 and other moyamoya angiopathy (MMA)-related genes.

Methods: The authors evaluated 14 consecutive cases of qMMD, whose underlying conditions included autoimmune disease, head irradiation, meningitis/pachymeningitis, and Turner syndrome, and 9 cases of hyperthyroidism-associated MMD (hMMD).

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Background And Objectives: Traumatic brain injury (TBI) is frequently characterized by chronic motor deficits. Therefore, this clinical trial assessed whether intracranial implantation of allogeneic modified mesenchymal stromal (SB623) cells can improve chronic motor deficits after TBI.

Methods: Post hoc analysis of the double-blind, randomized, prospective, surgical sham-controlled, phase 2, STEMTRA clinical trial (June 2016 and March 2019) with 48 weeks of follow-up was conducted.

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Article Synopsis
  • A 31-year-old woman experienced a sudden headache and altered consciousness, leading to the discovery of a left acute subdural hematoma and a small aneurysm on her left distal posterior cerebral artery, which was treated with coil embolization.
  • Two weeks later, she developed complete left hemiplegia due to an occluded right middle cerebral artery, requiring a mechanical thrombectomy that successfully restored blood flow.
  • Ultimately, she was diagnosed with infective endocarditis after positive blood cultures revealed bacterial presence and a TEE identified vegetation on the mitral valve; she was treated with penicillin and discharged without neurological deficits.
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Article Synopsis
  • * Of the 56 patients studied, a significant number experienced hemorrhagic events, especially associated with anterior choroidal artery (AchA) dilatation; these patients showed worse health outcomes compared to those with ischemic onset.
  • * Hemorrhagic events were found to be the most common and serious complication for those aged 60 and above with MMD, with specific factors like AchA dilatation indicating the risk of future hemorrhages in asym
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Article Synopsis
  • - The study investigates how genetic factors influence postoperative artery development in patients with moyamoya disease (MMD), specifically focusing on the relationship between genetic variants and the growth of certain donor arteries after surgery.
  • - Researchers analyzed data from 63 patients undergoing revascularization surgery and found that the RNF213 p.Arg4810Lys variant was significantly linked to the development of the deep temporal artery (DTA), while age and health conditions like hypertension and hyperlipidemia affected artery growth negatively.
  • - Results highlighted that individuals with the RNF213 p.Arg4810Lys variant experienced better improvement in DTA after surgery, suggesting that a comprehensive understanding of RNF213 variants could enhance predictions of surgical outcomes for moyam
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Article Synopsis
  • Ependymomas are diverse tumors with specific types based on where they occur and their molecular characteristics, with spinal ependymomas (SP-EPN) being the most common type found in the spinal cord of both children and adults.
  • Research revealed limited molecular data on SP-EPN, with known genetic changes including losses on chromosome 22q and mutations in NF2, but this study aimed to fill the gaps by analyzing transcriptomic, epigenetic, genetic, and clinical data from a large cohort.
  • The study identified two subtypes of SP-EPN: subtype A, associated with known NF2 mutations and more severe disease, and subtype B, characterized by different genetic alterations and more stable NF2 expression, helping to
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Background: Moyamoya disease is a bilateral steno-occlusive disease involving the cerebral vasculature. While some patients are affected by procedure-related ipsilateral ischemia, ischemic complications contralateral to the revascularization are rarely observed.

Methods: We retrospectively investigated 135 hemispheres (103 patients) that underwent revascularization in our institution between April 2006 and September 2022.

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Objective: The characteristics of pregnancy and delivery in patients with moyamoya disease (MMD) remain unclear. We retrospectively investigated perinatal outcomes in patients with MMD to evaluate the risks associated to this condition.

Materials And Methods: Clinical data of women with MMD who delivered at the University of Tokyo Hospital between 2000 and 2021 were collected.

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Objective: With the increasing incidence of malignancies, the importance of cancer-associated stroke is emphasized. Although moyamoya disease is a leading cause of stroke, no reports have documented cancer-associated stroke in patients with this condition. We aimed to investigate cerebrovascular events during malignancy treatments in patients with moyamoya disease.

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Objective: Prevention of rebleeding events is crucial for patients with hemorrhagic moyamoya disease (MMD), as these increase the risk of mortality. Bypass surgery is effective in preventing subsequent hemorrhage, particularly in patients with posterior hemorrhage, but its efficacy in those with anterior hemorrhage remains unclear. We analyzed the effects of surgical intervention, stroke risk factors, and radiological features on rebleeding events.

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Clinical implications of RNF213 genetic variants, other than p.Arg4810Lys, in moyamoya disease (MMD), remain unclear. This study aimed to investigate the association of RNF213 variants with clinical phenotypes in MMD.

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Objective: Cerebrovascular events in moyamoya disease are mainly classified into ischemic or hemorrhagic onset. It is rare for one patient to develop both ischemia and hemorrhage in moyamoya disease; detailed clinical course and genetic characteristics of such patients have not been elucidated. We aimed to clarify the clinical features of patients with both ischemic and hemorrhagic cerebrovascular events.

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The genetic background of intracranial artery stenosis (ICAS), a major cause of ischemic stroke, remains elusive. We performed the world's first genome-wide association study (GWAS) of ICAS using DNA samples from Japanese subjects, to identify the genetic factors associated with ICAS and their correlation with clinical features. We also conducted a phenome-wide association study (PheWAS) of the top variant identified via GWAS to determine its association with systemic disease.

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Neurosyphilis is an infection of the central nervous system by . Gummatous neurosyphilis, especially spinal syphilitic gumma, is an exceedingly rare manifestation and may be misdiagnosed as other tumors due to its rarity. A 42-year-old man with a medical history of treatment for syphilis presented with rapidly progressive leg paralysis, leg sensory disturbance, and bladder and rectal disturbance.

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The relationship between RNF213 c.14429G > A (p.Arg4810Lys) heterozygous variants and clinical manifestation in patients with Moyamoya disease (MMD) remains unclear.

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Moyamoya disease is characterized by severe stenosis at the ends of the bilateral internal carotid arteries and the development of collateral circulation. The disease is very diverse in terms of age at onset, onset patterns, radiological findings, and genetic phenotypes. The pattern of onset is mainly divided into ischemic and hemorrhagic onsets.

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Ischemic neuronal death causes serious lifelong neurological deficits; however, there is no proven effective treatment that can prevent neuronal death after the ischemia. We investigated the feasibility of mRNA therapeutics for preventing the neuronal death in a rat model of transient global ischemia (TGI). By intraventricular administration of mRNA encoding brain-derived neurotrophic factor (BDNF) using a polymer-based carrier, polyplex nanomicelle, the mRNA significantly increased the survival rate of hippocampal neurons after TGI, with a rapid rise of BDNF in the hippocampus.

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Objective: To determine whether chronic motor deficits secondary to traumatic brain injury (TBI) can be improved by implantation of allogeneic modified bone marrow-derived mesenchymal stromal/stem cells (SB623).

Methods: This 6-month interim analysis of the 1-year double-blind, randomized, surgical sham-controlled, phase 2 Stem Cell Therapy for Traumatic Brain Injury (STEMTRA) trial (NCT02416492) evaluated safety and efficacy of the stereotactic intracranial implantation of SB623 in patients with stable chronic motor deficits secondary to TBI. Patients in this multicenter trial (n = 63) underwent randomization in a 1:1:1:1 ratio to 2.

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Background And Purpose: Few previous studies have comprehensively explored the relationship between the onset pattern of adult moyamoya disease and risk factors for stroke. We performed a retrospective analysis focusing on risk factors for stroke and related findings on magnetic resonance imaging/angiography with respect to the pattern of disease onset. We also examined whether risk factors for stroke were associated with an increased risk for symptomization in asymptomatic patients.

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Background: Giant fusiform and dolichoectatic aneurysms of the basilar trunk and vertebrobasilar junction (BTVBJ-GFDA) are extremely difficult to treat.

Objective: To evaluate factors influencing survival and outcome of BTVBJ-GFDA by performing a retrospective multicenter cohort study.

Methods: A total of 32 patients with BTVBJ-GFDA were included in this study.

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Intracranial artery stenosis (ICAS) is the most common cause of ischemic stroke worldwide. RNF213 single nucleotide variant c.14429G > A (p.

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Orbital roof fracture is a relatively rare trauma. In most cases, surgical intervention is not needed since the fracture is slight. However, invasive surgical procedures are inevitable once pulsatile exophthalmos occurs if vision impairment is to be avoided.

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