• Journal of Korean Neurosurgical Society
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• v.63 no.1
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• pp.34-44
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• 2020

Objective : Despite widespread use of flow diverters (FDs) to treat aneurysms, the exact healing mechanism associated with FDs remains poorly understood. We aim to describe the healing process of aneurysms treated using FDs by demonstrating the histopathologic progression in a canine aneurysm model. Methods : Twenty-one side wall aneurysms were created in common carotid artery of eight dogs and treated with two different FDs. Angiographic follow-ups were done immediately after placement of the device, 4 weeks and 12 weeks. At last follow-up, the aneurysm and the device-implanted parent artery were harvested. Results : Histopathologic findings of aneurysms at 4 weeks follow-up showed intra-aneurysm thrombus formation in laminating fashion, and neointimal thickening at the mid-segment of aneurysm. However, there are inhomogenous findings in aneurysms treated with the same type of FD showing same angiographic outcomes. At 12 weeks, aneurysms of complete and near-complete occlusion revealed markedly shrunken aneurysm filled with organized connective tissues with thin neointima. Aneurysms of incomplete occlusion at 12 weeks showed small amount of organized thrombus around fringe neck and large empty space with thick neointmal formation. Neointimal thickness and diameter stenosis was not significantly different between the groups of FD specification and follow-up period. Conclusion : Intra-aneurysmal thrombus formation and organization seem to be an important factor for the complete occlusion of aneurysms treated using the FD. Neointimal formation could occur along the struts of the FD independently of intra-aneurysmal thrombus formation. However, neointimal formation could not solely lead to complete aneurysm healing.

• Journal of Korean Neurosurgical Society
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• v.45 no.4
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• pp.236-239
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• 2009

Carotid occlusion is an inevitable therapeutic modality for the treatment of complex aneurysms such as giant, traumatic, and intracavernous aneurysms. Late complications of carotid occlusion include 'de novo' aneurysm formation at a distant site because of hemodynamic changes in the circle of Willis. We report a case of de novo aneurysm in a vessel that appeared to be normal on initial angiography. The patient developed an anterior communicating artery aneurysm and marked growth of a basilar bifurcation aneurysm 9 years after trapping of the left internal carotid artery for the treatment of a ruptured large saccular aneurysm involving ophthalmic and cavernous segments. We propose that patients who undergo therapeutic carotid occlusion should be periodically followed by magnetic resonance angiography or computed tomographic angiography to evaluate the possibility of de novo aneurysm formation; this advice is in line with previous reports.

• Journal of computational fluids engineering
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• v.16 no.4
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• pp.64-71
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• 2011

Cerebral aneurysm mostly occurs at a bifurcation of the circle of Willis. When the cerebral aneurysm is ruptured, a disease like subarachnoid hemorrhage and stroke is caused and this can be even deadly for patients. Generally it is known that causes of the intracranial aneurysm are a congenital deformity of the artery and pressure or shear stress from the blood flow. A blood flow pattern and the geometry of the blood vessel are important factors for the aneurysm formation. Research for several hemodynamic indices has been performed and these indices can be used for the prediction of aneurysm initiation and rupture. Therefore, the numerical analysis was performed for hemodynamic characteristics of the blood flow through the cerebral artery applying the various bifurcation angle and flow rate ratio. We analyze the flow characteristics using indices from the results of the numerical simulation. In addition, to investigate the flow pattern in the aneurysm according to the bifurcation angle and the flow rate ratio, we performed the numerical simulation on the supposition that the aneurysm occurs.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.161-168
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• 2011

Cerebral aneurysm mostly occurs at a bifurcation of the circle of Willis. When the cerebral aneurysm is ruptured a disease like subarachnoid hemorrhage and stroke is caused and this can be even deadly for patients. Generally it is known that causes of the intracranial aneurysm are a congenital deformity of the artery and pressure or shear stress from the blood flow. A blood flow pattern and the geometry of the blood vessel are important factors for the aneurysm formation. Research for several hemodynamic indices has been performed and these indices can be used for the prediction of aneurysm initiation and rupture. Therefore, the numerical analysis was performed for hemodynamic characteristics of the blood flow through the cerebral artery applying the various bifurcation angle and flow rate ratio. We analyze the flow characteristics using indices from the results of the numerical simulation. In addition, to investigate the flow pattern in the aneurysm according to the bifurcation angle and the flow rate ratio, we performed the numerical simulation on the supposition that the aneurysm occurs.

• Journal of Korean Neurosurgical Society
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• v.50 no.5
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• pp.453-456
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• 2011

Many tumors have been reported to coexist with cerebral aneurysm. However, intracranial dermoid cysts associated with cerebral aneurysm are very rare. We report a case in which rupture of a cerebral aneurysm resulted in a ruptured dermoid cyst. We present this interesting case and review current literature about the relationship between tumors and aneurysm formation.

• Journal of Korean Neurosurgical Society
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• v.39 no.1
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• pp.46-51
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• 2006

Objective : An Intracranial aneurysm is an important acquired cerebrovascular disease that can cause a catastrophic subarachnoid hemorrhage. Atherosclerosis is one of possible mechanism, but its contribution to aneurysm formation is unclear. Human apolipoprotein E[apoE] is best known for its arterial protection from atherosclerosis. In this study we observe apoE expression in experimental cerebral aneurysms of rats to elucidate the role of apoE in the process of cerebral aneurysm formation. Methods : Twenty-four male 7-week-old Sprague-Dawley strain rats received a cerebral aneurysm induction procedure. One month[12] and three months[12] after the operation, the rats were killed, their cerebral arteries were dissected, and the regions of the bifurcation of the right anterior cerebral artery-olfactory artery [ACA-OA] bifurcations were examined histologically and immunohistochemically. Results : In the 1 month group [n=12], the ACA-OA bifurcation showed no aneurysmal change in 7 rats and early aneurysmal change in 5 rats. In the 3 months group (n=12), the bifurcation showed no aneurysmal change in 2 rats and an advanced aneurysm in 10 rats. ApoE expression were in 3 specimen in early aneurysmal change, but not in advanced aneurysms. Conclusion : ApoE expression in early aneurysmal wall suggests a possible role for apoE in early events leading to aneurysm formation. Further studios are necessary to elucidate the exact role of apoE in the pathophysiology of cerebral aneurysm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.124-127
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• 2002

Ceil embolisation technique has been used to treat the intracranial aneurysms. Microcoils inserted into the aneurysm sac induce the blood flow stagnation inside the aneurysm sac, which causes the thrombus formation and embolisation of aneurysm. Since the intraaneurysmal flow patterns affect the embolisation process, we want to measure the flow field for different locations of coil inside the aneurysm sac . Lateral aneurysm models are manufactured using rapid prototyping, and the velocity fields are measured using particle image velocitimeter. Distally blocked models showed less flow into the aneurysm sac comparing to proximally blocked models. Also blocking the neck of aneurysm showed better inflow blocking comparing to blocking the dome of aneurysm. These results suggest that distal neck should be the preferred locations of coil for aneurysm embolisation.

• Journal of Korean Neurosurgical Society
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• v.54 no.3
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• pp.236-238
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• 2013

Rapidly developed de novo aneurysm is very rare. We present a rapidly developed and ruptured de novo anterior communicating aneurysm 8 days after the rupture of another aneurysm. This de novo aneurysm was not apparent in the initial 3-dimensional computed tomography and digital subtraction angiography. We reviewed the literature and discussed possible mechanisms for the development of this de novo aneurysm.

• Journal of Chest Surgery
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• v.24 no.2
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• pp.202-205
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• 1991

Development of an aneurysm in the thoracic aorta, intercostal arteries, or cerebral vessels is not an uncommon occurrence in patients with coarctation of the aorta. The mechanism whereby coarctation predisposes to aneurysm formation is incompletely understood and we suggest that in this case, an intrinsic factor in the wall of the aorta underlies the formation of aneurysms. Recently we experienced one case of COA associated with the thoracic aortic aneurysm and operation was done successfully. PDA was simply ligated and the aorta was cross-clamped proximally and distally and the area of constriction or aneurysmal site were excised. Postoperative course was uneventful and the patient was discharged 2 weeks after operation. Hypertension at upper extremities was controlled without any antihypertensive drugs after operation and the degree of regurgitation of mitral valve was improved postoperatively but long-term follow-up should be necessary.

• Journal of Biomedical Engineering Research
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• v.22 no.6
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• pp.535-542
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• 2001

Endovascular embolization technique using a steno is currently used to treat the wide neck aneurysm. Since intraaneurysmal flow characteristics affect thrombus formation and embolisation process. flow visualization technique incorporating photochromic dye was used to elucidate hemodynamic changes by stenting Inside the fusiform aneurysm models. Qualitative observation of flow field and measurement of wall shear rates were Performed at five aneurysm wall locations under pulsatile flow. Intraaneurysmal flow motion was reduced and sluggish vortical motion was maintained during late deceleration phase by stenting. Also wall shear rates were reduced and OSI's were increased in the stented model. These flow characteristics Provide hemodynamic environment favorable for thrombus formation and intimal hyperplasia. The results of this study show hemodynamic changes by stenting Promote thrombus formation and aneurysm embolisation.