Publications by authors named "Shinichiro Sugiyama"

Background And Objectives: Ruptured aneurysms visualized by vessel wall MRI (VW-MRI) exhibit characteristic aneurysm wall enhancement (AWE). A secondary bulge of the aneurysmal wall, called a bleb, is often the site of rupture in ruptured aneurysms. We hypothesized that a higher degree of AWE would identify the rupture point in aneurysms with multiple blebs.

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Pathological examination is essential for the diagnosis and treatment of pancreatic ductal adenocarcinoma (PDAC). Moreover, a reliable pathological diagnosis is extremely important for improving prognosis, especially in early-stage PDAC. This study prospectively evaluated the usefulness of repeated pancreatic juice cytology (PJC) using an endoscopic nasopancreatic drainage (ENPD) catheter for the diagnosis of PDAC.

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Background: Hemifacial spasm (HFS) is caused by neurovascular contact along the facial nerve's root exit zone (REZ). The authors report a rare HFS case that was associated with ipsilateral subclavian steal syndrome (SSS).

Observations: A 42-year-old man with right-sided aortic arch presented with progressing left HFS, which was associated with ipsilateral SSS due to severe stenosis of the left brachiocephalic trunk.

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Purpose: Recent computational fluid dynamics (CFD) studies have demonstrated the concurrence of atherosclerotic changes in regions exposed to prolonged blood residence. In this proof-of-concept study, we investigated a small but homogeneous cohort of large, cavernous carotid aneurysms (CCAs) to establish the clinical feasibility of CFD analysis in treatment planning, based on the association between pathophysiology and hemodynamics.

Methods: This study included 15 patients with individual large CCAs.

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Incomplete stent expansion (IncSE) is occasionally seen in flow-diversion (FD) treatment of intracranial aneurysms; however, its haemodynamic consequences remain inconclusive. Through a parametric study, we quantify the aneurysmal haemodynamics subject to different severities of IncSE occurring in different portions of the stent. Two patient cases with IncSE confirmed in vivo were studied.

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Early diagnosis of pancreatic ductal adenocarcinoma (PDAC) is challenging but essential for improving its poor prognosis. We established a multicenter study to clarify the clinicopathological features, and to propose new algorithm for early diagnosis of PDAC. Ninety-six patients with stage 0 and IA PDAC were enrolled from 13 high-volume centers.

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Carotid web has been recognized as a rare cause of ischemic stroke with high recurrence rate. We describe a 48-year-old woman with carotid web who developed embolic stroke. We obtained a fresh thrombus from the internal carotid artery when carotid endarterectomy was performed.

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We report a 77-year-old woman with marked enlargement of a middle cerebral artery (MCA) aneurysm 4 years after the successful intra-aneurysmal embolization of an ipsilateral large internal carotid artery (ICA) aneurysm. She intially presented with right third cranial nerve palsy due to a large ICA aneurysm, 20.8 mm in diameter.

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Background: Spinal cord high-grade glioma has poor prognosis. Especially, no treatment protocols have been established for recurrent cases.

Objective: To apply a novel treatment method, convection-enhanced delivery (CED), for recurrent high-grade glioma.

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Objective: Recent MR vessel wall imaging studies have indicated intracranial aneurysms in the active state could show circumferential enhancement along the aneurysm wall (CEAW). While ruptured aneurysms frequently show CEAW, CEAW in unruptured aneurysms at the evolving state (i.e.

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Purpose: Image-based computational fluid dynamics (CFD) is widely used to predict intracranial aneurysm wall shear stress (WSS), particularly with the goal of improving rupture risk assessment. Nevertheless, concern has been expressed over the variability of predicted WSS and inconsistent associations with rupture. Previous challenges, and studies from individual groups, have focused on individual aspects of the image-based CFD pipeline.

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Purpose: Advanced morphology analysis and image-based hemodynamic simulations are increasingly used to assess the rupture risk of intracranial aneurysms (IAs). However, the accuracy of those results strongly depends on the quality of the vessel wall segmentation.

Methods: To evaluate state-of-the-art segmentation approaches, the Multiple Aneurysms AnaTomy CHallenge (MATCH) was announced.

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The most frequently used option to reconstruct the anterior cerebral artery (ACA) is an ACA-ACA side-to-side anastomosis. The long-term outcome and complications of this technique are unclear. The authors report a case of a de novo aneurysm arising at the site of A3-A3 anastomosis.

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Background: The management of intracranial aneurysm (IA) is challenging. Clinicians often rely on varied and intuitively disparate ways of evaluating rupture risk that may only partially take into account complex hemodynamic and morphologic factors. We developed a prototype of a clinically oriented, streamlined, computational platform, AView, for rapid assessment of hemodynamics and morphometrics in clinical settings.

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Background: Identification of rupture sites in patients with multiple intracranial aneurysms is largely based on aneurysm size, location, and shape. Finding circumferential enhancement along the aneurysm wall (CEAW) on magnetic resonance (MR) vessel wall imaging was recently shown to be indicative of ruptured aneurysm.

Objective: To investigate the hypothesis that a higher degree of CEAW would identify the site of rupture in patients with multiple aneurysms.

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OBJECTIVE Risk factors for aneurysm rupture have been extensively studied, with several factors showing significant correlations with rupture status. Several studies have shown that aneurysm shape and hemodynamics change after rupture. In the present study the authors investigated a static factor, the bifurcation angle, which does not change after rupture, to understand its effect on aneurysm rupture risk and hemodynamics.

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Background: Convection-enhanced delivery (CED) is a technique allowing local infusion of therapeutic agents into the central nervous system, circumventing the blood-brain or spinal cord barrier.

Objective: To evaluate the utility of nimustine hydrochloride (ACNU) CED in controlling tumor progression in an experimental spinal cord glioma model.

Methods: Toxicity studies were performed in 42 rats following the administration of 4 μl of ACNU CED into the mid-thoracic spinal cord at concentrations ranging from 0.

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This was a proof-of-concept computational fluid dynamics (CFD) study designed to identify atherosclerotic changes in intracranial aneurysms. We selected 3 patients with multiple unruptured aneurysms including at least one with atherosclerotic changes and investigated whether an image-based CFD study could provide useful information for discriminating the atherosclerotic aneurysms. Patient-specific geometries were constructed from three-dimensional data obtained using rotational angiography.

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Background: Transcranial Doppler (TCD) is used to monitor cerebral vasospasm after subarachnoid hemorrhage (SAH), but its diagnostic ability is reported to be limited. Therefore, the purpose of this study was to investigate the relationship between the diagnosability of TCD and the localization of the vasospasm.

Methods: This retrospective study included 20 patients who presented with symptomatic vasospasm after SAH.

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Background And Purpose: Hemodynamic forces may play a role in the recanalization of coiled aneurysms. The purpose of this study was to investigate the influence of presurgical hemodynamics on the efficacy of coil embolization for basilar tip aneurysms.

Methods: We identified 82 patients who underwent endovascular coil embolization for basilar tip aneurysms with a follow-up of >1 year.

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Temozolomide is a standard chemotherapy agent for malignant gliomas, but the efficacy is still not satisfactory. Therefore, combination chemotherapy using temozolomide with other anti-tumor compounds is now under investigation. Here we studied the mechanism of the synergistic anti-tumor effect achieved by temozolomide and doxorubicin, and elucidated the inhibitory effect of temozolomide on P-glycoprotein (P-gp).

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OBJECT Convection-enhanced delivery (CED) is a method for distributing small and large molecules locally into the interstitial space of the spinal cord. Delivering these molecules to the spinal cord is otherwise difficult due to the blood-spinal cord barrier. Previous research has proven the efficacy of CED for delivering molecules over long distances along the white matter tracts in the spinal cord.

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With the increased availability of computational resources, the past decade has seen a rise in the use of computational fluid dynamics (CFD) for medical applications. There has been an increase in the application of CFD to attempt to predict the rupture of intracranial aneurysms, however, while many hemodynamic parameters can be obtained from these computations, to date, no consistent methodology for the prediction of the rupture has been identified. One particular challenge to CFD is that many factors contribute to its accuracy; the mesh resolution and spatial/temporal discretization can alone contribute to a variation in accuracy.

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Surgical treatments should be considered for vertebral artery fusiform aneurysms, which become symptomatic due to cerebral ischemia or mass effect. Ischemic complication is one of the major problems after surgical or endovascular trapping, which is associated with unfavorable outcomes. The authors present a case with growing vertebral artery (VA) fusiform aneurysm with ischemic onset successfully treated with outflow occlusion with occipital artery-posterior inferior cerebellar artery (OA-PICA) bypass.

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