Publications by authors named "Kenji Uda"

Selecting an appropriate microcatheter tip shape for paraclinoid aneurysms is difficult. Therefore, we devised an original simple and uniform three-dimensional (3D) spiral-shaping method of microcatheter and validated the characteristics and usefulness of this method for coil embolization of paraclinoid aneurysms using patient-specific silicone models. These silicone models were produced based on clinical data from four patients with four paraclinoid aneurysms that underwent endovascular treatment using the 3D spiral-shaping method.

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Article Synopsis
  • * A randomized trial in China involved 269 patients who were assigned to start antiplatelet therapy early (3 days post-surgery) or late (30 days post-surgery) to evaluate safety and effectiveness on major cardiovascular events.
  • * The study, which involved patients mostly around 60 years old, aimed to measure occurrences of new major ischaemic events and intracranial bleeding within 90 days after surgery, and is officially registered under ClinicalTrials.gov number NCT04820972.
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Objective: Transient neurological deficits (TNDs) are known to develop after direct bypass for Moyamoya disease and may be risk factors for subsequent stroke. However, the factors involved in the development of TNDs and stroke after indirect revascularization alone, including their association with subsequent stroke, remain unclear. The purpose of this study was to investigate this issue.

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Objective: This study aimed to analyze whether the development of donor vessels after combined revascularization surgery for moyamoya disease (MMD) is related to cerebral blood flow (CBF) changes.

Methods: We retrospectively reviewed the charts of 11 adult (12 hemispheres) and 13 pediatric (19 hemispheres) patients who underwent combined revascularization in our department. The total vessel cross-sectional area (TVA) was the sum of the cross-sectional areas of the superficial temporal, middle meningeal, and deep temporal arteries imaged using time-of-flight magnetic resonance angiography.

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We conducted a study to understand the characteristics of the finishing coils to select the appropriate coil for the final stage of embolization. Consequently, experimental embolization was performed on a 10 mm spherical silicone aneurysm filled with radiolucent coils, which simulated a volume embolization ratio of 20%. Nine different coils (i-ED complex ∞ SilkySoft, SilkySoft, ExtraSoft, V-Trak HyperSoft helical, Barricade 10 complex finishing, Optima complex 10 soft, Target 360 Ultra, Galaxy G3 mini, and Axium prime 3D ExtraSoft) were analyzed six times at random.

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Objective: Transient neurological events (TNEs) are among the most important events after revascularization surgery in pediatric patients with moyamoya disease (MMD). Although hemodynamic changes and crying are representative factors of TNEs, brain compression by encephalomyosynangiosis (EMS) is another important cause of TNEs. Therefore, the authors assumed that making the EMS as thin as possible reduces the frequency of TNEs.

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Background: Intraorbital arteriovenous fistula (IOAVF) is a rare type of intracranial fistula that presents with ocular signs similar to those of cavernous sinus dural arteriovenous fistula. The treatment of IOAVF is based on the vascular architecture of each case due to its infrequent occurrence. The authors report the case of an IOAVF that was successfully treated with embolization via the facial vein, with good outcomes.

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Background: Dural arteriovenous fistulas (DAVFs) with cortical venous reflux (CVR) carry a high risk for neurological sequelae or death. Recently, transverse-sigmoid sinus DAVFs were shown as good indications for transarterial embolization (TAE) with ONYX. Here, we compared the effectiveness and safety of conventional transvenous embolization (TVE) with those of TAE with ONYX for transverse-sigmoid sinus DAVFs with CVR.

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Purpose: Artificial intelligence (AI)-based three-dimensional angiography (3D-A) was reported to demonstrate visualization of cerebral vasculature equivalent to that of three-dimensional digital subtraction angiography (3D-DSA). However, the applicability and efficacy of the AI-based 3D‑A algorithm have not yet been investigated for 3D-DSA micro imaging. In this study, we evaluated the usefulness of the AI-based 3D‑A in 3D-DSA micro imaging.

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A 61-year-old man presented with massive epistaxis, amaurosis, nausea, and severe headache. A detailed examination revealed a subarachnoid hemorrhage and prolactinoma. Angiography showed a small internal carotid artery pseudoaneurysm and inadequate collateral circulation; thus, uncomplicated coil embolization was performed.

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Purpose: To examine the specific changes that occur in the expression levels of extracellular vesicle-derived microRNAs (miRNAs) in intracranial cerebrospinal fluid (CSF) in moyamoya disease.

Methods: Patients with arteriosclerotic cerebral ischemia were used as controls to eliminate the effects of cerebral ischemia. Intracranial CSF was collected from moyamoya disease and control patients during bypass surgery.

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Article Synopsis
  • Thromboembolic complications can arise when treating cerebral aneurysms with a flow diverter device, as shown in a case involving a 72-year-old woman with a large cavernous carotid aneurysm.
  • During the deployment of the Flow Re-Direction Endoluminal Device (FRED), issues like abnormal foreshortening and stent slipping led to occlusion of the internal carotid artery due to in-stent thrombosis.
  • After removing the thrombus-filled FRED and modifying the antiplatelet regimen, a subsequent Pipeline Flex device was implanted a month later without any further thromboembolic events.
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This study sought to establish an experimental aneurysm model of visualizing coil insertion using radiolucent nylon coils. Moreover, this study aimed to clarify the characteristics and differences of each coil and use them clinically as indices of coil selection. The coil insertion test was performed on the 10 mm spherical silicone aneurysm model filled to a nylon coil volume embolization ratio of 11.

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Background: Two-dimensional digital subtraction angiography (2D-DSA) and conventional three-dimensional digital subtraction angiography (3D-DSA) are used for the detailed analysis of dural arteriovenous fistula (DAVF). Recently, four-dimensional digital subtraction angiography (4D-DSA), a novel technology, has been attracting attention. The current study aimed to evaluate the capability of 4D-DSA in assessing anatomical angioarchitecture in DAVF.

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Background: The aim of this study was to investigate the association between early postoperative slow flow in bypass grafts and preoperative focal cerebral blood flow (CBF) in patients who underwent combined surgery for moyamoya disease (MMD).

Methods: The subjects were 18 patients (22 surgeries) who underwent single photon emission computed tomography (SPECT) before surgery. The CBF value of the middle cerebral artery territory was extracted from the SPECT data, and the value relative to the ipsilateral cerebellar CBF (relative CBF, or RCBF) was calculated.

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Background: In patients with moyamoya disease (MMD) who receive superficial temporal artery (STA) to middle cerebral artery (MCA) bypass, hypoperfusion remote from the anastomosis site rarely occurs. Watershed shift due to direct bypass has been proposed as the mechanism; however, no report has confirmed this phenomenon using angiography.

Observations: A 48-year-old man presented with transient weakness in his left arm.

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Background: Remote cerebral infarction after combined revascularization of the middle cerebral artery (MCA) territory is rare in patients with moyamoya disease (MMD) with a fetal-type posterior communicating artery (PCoA).

Observations: A 57-year-old woman developed numbness in her right upper limb and transient motor weakness and was diagnosed with MMD. She also had a headache attack and a scintillating scotoma in the right visual field.

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In this article, we report a case wherein a brain tumor was suspected based on computed tomography and magnetic resonance imaging findings. We made an initial diagnosis of malignant brain tumor based on methionine-positron emission tomography (PET) findings, but the correct diagnosis was dural arteriovenous fistula (DAVF). The patient was a 45-year-old man with DAVF who developed headache.

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Background: Transient neurological deficits (TNDs) develop after cerebral revascularization in patients with moyamoya disease (MMD). The authors report a rare pediatric MMD case with extensive decreased cerebral blood flow (CBF) and prolonged TNDs after combined revascularization.

Observations: A 9-year-old boy presented with transient left upper limb weakness, and MMD was diagnosed.

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Objective: The protocol for antiplatelet therapy after stent-assisted coil embolization (SACE) for intracranial aneurysms is not well established. In particular, the indications for single antiplatelet therapy (SAPT) discontinuation remain controversial. The authors investigated the long-term outcomes of SAPT discontinuation after SACE among patients at a single institution.

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Objective: Moyamoya disease (MMD) is a rare cerebrovascular disease characterized by progressive stenosis of the internal carotid artery (ICA) and secondary formation of collateral vessels. Revascularization surgery is performed in patients with MMD to prevent stroke; however, the pathogenesis of MMD remains unknown. Recently, long noncoding RNAs (lncRNAs) have been found to play a key role in gene regulation and are implicated in various vascular diseases.

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Objective: After revascularization surgery in pediatric patients with moyamoya disease (MMD), resting and avoiding crying is important. However, this inaction is often difficult because of pain or anxiety. Dexmedetomidine (DEX), which has sedative and analgesic properties, may be useful in reducing those uncomfortable conditions; however, its common side effects include bradycardia and hypotension, which have a risk of decreasing the cerebral blood flow.

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Balloon test occlusion (BTO) is an angiographic test to evaluate ischemic tolerance after permanent occlusion of an internal carotid artery (ICA). BTO can simulate ischemia caused by parent artery occlusion and can be used to select a suitable bypass surgery using specific criteria. On the other hand, a postoperative thrombus can form despite proper case selection, optimal radiological evaluation, and an appropriate surgical strategy.

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Objectives: Congenital afibrinogenemia is an autosomal recessive inherited disorder that can cause thrombotic as well as hemorrhagic events. We describe a case of repeated mild ischemic strokes due to a mural thrombus in the carotid artery and our medical treatment.

Case Description: A 49-year-old woman with congenital afibrinogenemia developed two minor ischemic strokes in two months.

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