• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.251-257
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• 2006

The performance of face recognition methods using subspace projection is directly related to the characteristics of their basis images, especially in the cases of local distortion or partial occlusion. In order for a subspace projection method to be robust to local distortion and partial occlusion, the basis images generated by the method should exhibit a part-based local representation. We propose an effective part-based local representation method named locally salient ICA (LS-ICA) method for face recognition that is robust to local distortion and partial occlusion. The LS-ICA method only employs locally salient information from important facial parts in order to maximize the benefit of applying the idea of 'recognition by parts.' It creates part-based local basis images by imposing additional localization constraint in the process of computing ICA architecture I basis images. We have contrasted the LS-ICA method with other part-based representations such as LNMF (Localized Non-negative Matrix Factorization)and LFA (Local Feature Analysis). Experimental results show that the LS-ICA method performs better than PCA, ICA architecture I, ICA architecture II, LFA, and LNMF methods, especially in the cases of partial occlusions and local distortion

• Journal of Korean Neurosurgical Society
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• v.55 no.6
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• pp.313-320
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• 2014

Objective : The purpose of this study is to demonstrate the technical feasibility and clinical efficacy of emergent carotid angioplasty and stenting (CAS) for acute stroke due to athero-thrombotic occlusion of the cervical internal carotid artery (ICA). Methods : Review of medical records identified 17 patients who underwent emergent CAS for treatment of athero-thrombotic occlusion of the cervical ICA with acute stroke between 2009 and 2013. Eleven patients (64.7%) presented with concomitant intracranial artery occlusion, which was treated primarily by mechanical thrombectomy after CAS. Results : Successful revascularization of the cervical ICA with emergent CAS was achieved in all patients. After CAS, intracranial recanalization with Thrombolysis in Cerebral Infarction ${\geq}2b$ flow was achieved in four of the 11 patients (36.4%). The overall recanalization rate (cervical ICA and intracranial artery) was 10 of 17 patients (58.8%). Symptomatic intracranial hemorrhage occurred in two patients (11.8%), resulting in death. Ten patients (58.8%) showed improvement (decrease in NIHSS score of ${\geq}4$ points) at seven days after recanalization. Nine patients (52.9%) showed a favorable outcome ($mRS{\leq}2$) at the last follow-up. A favorable outcome ($mRS{\leq}2$) was obtained in four of the six patients with isolated cervical ICA occlusion (4/6, 66.7%) and five of 11 patients with intracranial tandem occlusion (5/11, 45.5%). Conclusion : Emergent CAS for acute stroke due to athero-thrombotic occusion of the cervical ICA showed a good technical feasibility and favorable clinical outcome.

• Journal of Korean Neurosurgical Society
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• v.62 no.2
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• pp.201-208
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• 2019

Objective : In patients with internal carotid artery (ICA) occlusion, collateral middle cerebral artery (MCA) flow has a protective role against ischemia. However, some of these patients may experience initial major neurological deficits and major worsening on following days. Thus, we investigated the safety and efficacy of endovascular treatment (EVT) for ICA occlusion with collateral MCA flow by comparing clinical outcomes of medical treatment versus EVT. Methods : The inclusion criteria were as follows : 1) acute ischemic stroke with ICA occlusion and presence of collateral MCA flow on transfemoral cerebral angiography (TFCA) and 2) hospital arrival within 12 hours from symptom onset. The treatment strategy was made by the attending physician based on the patient's clinical status and results of TFCA. Results : Eighty-one patients were included (30 medical treatment, 51 EVT). The EVT group revealed a high incidence of intracranial ICA occlusion, longer ipsilesional MCA contrast filling time, and a similar rate of favorable clinical outcome despite a higher mean baseline the National Institutes of Health Stroke Scale (NIHSS) score. By binary logistic regression analysis, intravenous recombinant tissue plasminogen activator and EVT were independent predictors of favorable clinical outcome. In subgroup analysis based on stroke etiology, the non-atherosclerotic group showed a higher baseline NIHSS score, higher incidence of EVT, and a higher rate of distal embolization during EVT in comparison with the atherosclerotic group. Conclusion : In patients with ICA occlusion and collateral MCA flow, decisions regarding treatment strategy based on TFCA can help achieve favorable clinical outcomes. EVT strategy with respect to etiology of ICA occlusion might help achieve better angiographic outcomes.

• Journal of KIISE:Software and Applications
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• v.33 no.5
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• pp.481-488
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• 2006

The performance of face recognition methods using subspace projection is directly related to the characteristics of their basis images, especially in the cases of local distortion or partial occlusion. In order for a subspace projection method to be robust to local distortion and partial occlusion, the basis images generated by the method should exhibit a part-based local representation. We propose an effective part-based local representation method named locally salient ICA (LS-ICA) method for face recognition that is robust to local distortion and partial occlusion. The LS-ICA method only employs locally salient information from important facial parts in order to maximize the benefit of applying the idea of 'recognition by parts.' It creates part-based local basis images by imposing additional localization constraint in the process of computing ICA architecture I basis images. We have contrasted the LS-ICA method with other part-based representations such as LNMF (Localized Non-negative Matrix Factorization) and LFA (Local Feature Analysis). Experimental results show that the LS-ICA method performs better than PCA, ICA architecture I, ICA architectureII, LFA, and LNMF methods, especially in the cases of partial occlusions and local distortions.

• Journal of Korean Neurosurgical Society
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• v.51 no.5
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• pp.296-300
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• 2012

Internal carotid artery (ICA) trapping can be used for the treatment of giant intracranial aneurysms, blood blister-like aneurysms, and fusiform dissecting aneurysms. Fusiform dissecting aneurysms are challenging to treat surgically and endovascularly because of no definite neck and critical perforators. Surgical or endovascular trapping of the ICA with or without an extracranial-intracranial bypass has commonly been used as an effective method to treat these lesions, but balloon test occlusion (BTO) must be performed. Here, we report a case of a ruptured fusiform dissecting aneurysm of the distal ICA, which was successfully treated using an endovascular ICA trapping with a manual ICA compression test instead of BTO.

• Journal of Trauma and Injury
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• v.28 no.3
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• pp.190-194
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• 2015

Blunt cerebrovascular injury is defined as a vertebral or carotid arterial structural wall injury resulting from nonpenetrating trauma. Complete traumatic internal carotid artery occlusion is very rare condition accounting for 0.08~0.4 0f all trauma patients and believed to be associated with the greatest risk of ischemic stroke reported in 50~90% in a few small series. A 55-year-male was admitted with drowsy mentality and severe headache after a fall down accident. Brain computed tomography showed a subdural hematoma at the both frontal area with a fracture of the occipital skull bone. Two days after admission, he suddenly complained with a right side hemiparesis of motor grade 2. Brain magnetic resonance diffusion demonstrated multiple high flow signal changes from the left frontal and parietal lesion. Computed tomographic angiogram (CTA) revealed absence of the left ICA flow. Trans femoral cerebral angiography (TFCA) showed complete occlusion of the left internal carotid artery (ICA) at ophthalmic segment in the left ICA angiogram and flows on the left whole hemispheric lesions through the anterior communicating artery in the right ICA angiogram. We decided to conduct close observations as a treatment for the patient because of acute subdural hematoma and sufficient contralateral cerebral flow by perfusion SPECT scan. Two weeks after the accident, he was treated with heparin anticoagulation within INR 2~4 ranges. He recovered as the motor grade 4 without another neurologic deficit after 3 months.

• Journal of Korean Neurosurgical Society
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• v.60 no.2
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• pp.155-164
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• 2017

Objective : To evaluate the efficacy of balloon guiding catheter (BGC) during thrombectomy in anterior circulation ischemic stroke. Methods : Sixty-two patients with acute anterior circulation ischemic stroke were treated with thrombectomy using a Solitaire stent from 2011 to 2016. Patients were divided into the BGC group (n=24, 39%) and the non-BGC group (n=38, 61%). The number of retrievals, procedure time, thrombolysis in cerebral infarction (TICI) grade, presence of distal emboli, and clinical outcomes at 3 months were evaluated. Results : Successful recanalization was more frequent in BGC than in non-BGC (83% vs. 66%, p=0.13). Distal emboli occurred less in BGC than in non-BGC (23.1% vs. 57.1%, p=0.02). Good clinical outcome was more frequent in BGC than in non-BGC (50% vs. 16%, p=0.03). The multivariate analysis showed that use of BGC was the only independent predictor of good clinical outcome (odds ratio, 5.19 : 95% confidence interval, 1.07-25.11). More patients in BGC were successfully recanalized in internal carotid artery (ICA) occlusion with small retrieval numbers (<3) than those in non-BGC (70% vs. 24%, p=0.005). In successfully recanalized ICA occlusion, distal emboli did not occur in BGC, whereas nine patients had distal emboli in non-BGC (0% vs. 75%, p=0.001) and good clinical outcome was superior in BGC than in non-BGC (55.6% vs. 8.3%, p=0.01). Conclusion : A BGC significantly reduces the number of retrievals and the occurrence of distal emboli, thereby resulting in better clinical outcomes in patients with anterior circulation ischemic stroke, particularly with ICA occlusion.

• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.379-384
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• 2016

Objective : Mechanical thrombectomy (MT) for acute intracranial internal carotid artery (ICA) occlusion is often complicated by difficult revascularization and non-involved territory embolization possibly related with larger clot-burden. This study aims to evaluate the efficacy of proximal aspiration thrombectomy (PAT) using a balloon-tipped guide catheter for clot-burden reduction in such cases with period-to-period analysis (period 1 : standard MT without PAT; period 2 : PAT first, then standard MT for the remaining occlusion). Methods : Eighty-six patients who underwent MT for acute intracranial ICA occlusion were included in this analysis from the prospectively maintained stroke registry (33 patients in period 1 and 53 in period 2). In period 2, 'responder' was defined as a case where some amount of clot was retrieved by PAT and the following angiography showed partial or full recanalization. Results : Fifteen of fifty-three patients in period 2 (28.3%) were 'responders' to PAT. There was a significantly higher incidence of atrial fibrillation in the 'responder' subgroup. Period 2 showed a significantly shorter puncture-to-reperfusion time (94.5 minutes vs. 56.0 minutes; p=0.002), a significantly higher Thrombolysis in Cerebral Infarction of 2b-3 reperfusion (45.5% vs. 73.6%; p=0.009), but only a trend for better 3-month favorable outcome (mRS 0-2; 36.4% vs. 54.7%; p=0.097). There was no increase in the incidence of procedure-related complications or intracranial hemorrhage in period 2. Conclusion : A strategy of PAT before standard MT may result in shorter puncture-to-reperfusion time and better angiographic outcome than a strategy of standard MT for acute intracranial ICA occlusion.

• Journal of Korean Neurosurgical Society
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• v.47 no.6
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• pp.428-432
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• 2010

Objective : An effective intervention has not yet been established for patients with acute occlusion of the internal carotid artery (ICA). The aim of our study was to investigate the feasibility, safety, and efficacy of emergent stent placement of carotid artery to improve neurologic symptoms and clinical outcome. Methods : Of 84 consecutive patients with severe ICA stenosis who were admitted to our institution from March 2006 to May 2009, 10 patients with acute ICA occlusion (11.9%) underwent emergency carotid artery stent placement. We reviewed their records for neurologic outcome using the National Institutes of Health Stroke Scale (NIHSS) score, before and at 7 days after stent placement; clinical outcome using the modified Rankin Scale score (mRS) and Glasgow Outcome Scale (GOS); frequency of procedure-related complications; and recurrence rate of ipsilateral ischemic stroke within 90 days. Results : Carotid lesions were dilated completely in all patients. Median NIHSS scores before emergency stent placement and at 7 days were 16.6 and 6, respectively, showing significant improvement. Eight patients (80%) had favorable outcomes (mRS score 0-2 and GOS 4-5). Complications occurred in two patients (20%): stent insertion failed in one and an intracerebral hemorrhage occurred in the other. Ipsilateral ischemic stroke did not recur within 3 months. Conclusion : Emergency carotid artery stent placement can improve the 7-day neurologic outcome and the 90-day clinical outcome in selected patients with acute cerebral infarction.

• Journal of Korean Neurosurgical Society
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• v.49 no.3
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• pp.186-189
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• 2011

In recent years the immunocompromised population has increased rapidly to include people with acquired immune deficiency syndrome (AIDS), drug abusers, and transplant patients. Accordingly, the incidence of intracranial fungal infection has increased. Our institution experienced 2 cases of internal carotid artery (ICA) occlusion due to invasion of the cavernous sinus by an intracranial fungal infection. The first case was a 60-year-old man who presented with headache, eye pain, conjunctival injection, right-sided diplopia, and blurred vision. Infected tissues within the frontal and ethmoid sinuses were removed via bifrontal craniotomy and endoscopic sinus surgery through the Caldwell Luc approach. The second case was a 63-year-old woman who developed right-sided facial pain after a tooth extraction. The infection was not controlled despite continuous use of antifungal agents, resulting in death from sepsis. We believe that when intracranial fungal infection is suspected in a patient with orbital symptoms and a focal neurologic deficit, immediate angiographic investigation of possible ICA occlusion is warranted. Aggressive treatment with antifungal agents is the only way to improve prognosis.