Kyung-Yul Lee

Yonsei University, Sŏul, Seoul, South Korea

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Publications (51)91.72 Total impact

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    ABSTRACT: Background and purpose: The benefit of statins in acute stroke remains uncertain. Statins may prevent stroke recurrence during the acute stage of stroke via pleiotropic effects. However, statins may increase the risk of intracerebral hemorrhage. We investigated the effect and safety of rosuvastatin in acute stroke patients. Methods: This randomized, double-blind, multi-center trial compared rosuvastatin 20 mg and placebo in statin-naïve stroke patients who underwent diffusion-weighted imaging (DWI) within 48 hours after symptom onset. The primary outcome was occurrence of new ischemic lesions on DWI at 5 or 14 days. Results: This trial was stopped early after randomization of 316 patients due to slow enrollment. Among 289 patients with at least one follow-up imaging, the frequency of new ischemic lesions on DWI was not different between groups (rosuvastatin: 27/137, 19.7% vs. placebo: 36/152, 23.6%) (relative risk 0.83, 95% confidence interval 0.53-1.30). Infarct volume growth at 5 days (log-transformed volume change, rosuvastatin: 0.2±1.0 mm(3) vs. placebo: 0.3±1.3 mm(3); P=0.784) was not different, either. However, hemorrhagic infarction or parenchymal/subarachnoid hemorrhage on gradient-recalled echo magnetic resonance imaging occurred less frequently in the rosuvastatin group (6/137, 4.4%) than the placebo group (22/152, 14.5%, P=0.007). Among 314 patients with at least one dose of study medication, progression or clinical recurrence of stroke tended to occur less frequently in the rosuvastatin group (1/155, 0.6% vs. 7/159, 4.4%, P=0.067). Adverse events did not differ between groups. Conclusions: The efficacy of rosuvastatin in reducing recurrence in acute stroke was inconclusive. However, statin use was safe and reduced hemorrhagic transformation.
    No preview · Article · Feb 2016
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    ABSTRACT: Background and purpose: The Effect of Cilostazol in Acute Lacunar Infarction Based on Pulsatility Index of Transcranial Doppler (ECLIPse) study showed a significant decrease in transcranial Doppler pulsatility index (PI) with cilostazol treatment after 90 days of acute lacunar infarction. The aim of this analysis was to perform a subgroup analysis of the ECLIPse study to explore the relationship between serum uric acid (UA) and the volume of white matter hyperintensities (WMH) in patients with acute lacunar infarction. Methods: The ECLIPse was a multicenter, randomized, double-blind, placebo-controlled study conducted in Korea. For this subgroup analysis, WMH volume was measured for those subjects for whom FLAIR or T2-weighted images were available using semiautomated computerized software. Results: Of the 203 patients in 8 hospitals in the ECLIPse study, 130 in 6 hospitals were entered for this subgroup analysis. The mean age was 64.7 ± 9.95 years, and 20.8% were women. The mean WMH volume was 11.57 cm(3) (.13 to 68.45, median 4.86) and mean serum UA was 5.2 mg/dL (1.5 to 8.9). Multiple linear regression analysis revealed that age (P < .001) and serum UA (P = .013) were significantly associated with WMH volume. Age-adjusted scatterplots showed that serum UA level was positively related to WMH volume in patients with acute lacunar infarction (r = 0.275, P = .003). Conclusions: This study showed that serum UA was associated with cerebral WMH in patients with acute lacunar infarction.
    No preview · Article · Oct 2015 · Journal of neuroimaging: official journal of the American Society of Neuroimaging
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    ABSTRACT: Purpose: Hyperintense vessels (HVs) on fluid-attenuated inversion recovery (FLAIR) imaging are associated with the leptomeningeal collateral circulation in cases of arterial occlusive lesions. Nevertheless, the relationship between HVs on FLAIR imaging and arterial circulation time (ACT) on cerebral angiography has not been defined. Methods: We analyzed images of 11 patients with acute occlusion of the distal internal carotid artery or proximal middle cerebral artery and calculated the difference in ACT (DACT) between infarcted and normal hemispheres. ACT was defined as the time interval from the initial opacification of the ipsilateral or contralateral cavernous internal carotid artery to the late arterial phase of the carotid artery territories. We scored HVs on FLAIR imaging using a modified Alberta Stroke Program Early Computerized Tomography Score (ASPECTS) and determined collateral circulation by grading collateral flow. Results: We detected HVs on FLAIR images in 10 patients (median score, 4; range, 0 to 6). Comparison of infarcted and normal hemispheres demonstrated absent or subtle HVs on FLAIR imaging when the DACT was too short (<one second) or too long (>7.98 s) and prominent HVs with moderate DACT (2 to 5 s). The score of HVs on FLAIR was estimated well by DACT using a quadratic regression model (R(2) = 0.602) and better than by grading collateral flow (R(2) = 0.256). Conclusion: In cases of large arterial occlusion, the hyperintensity of vessels on FLAIR images may be dependent on arterial circulation time via retrograde filling of the leptomeningeal collateral circulation.
    Preview · Article · Sep 2015 · Magnetic Resonance in Medical Sciences
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    ABSTRACT: Nonsustained atrial tachycardia (NSAT) is known to appear more frequently in patients with paroxysmal atrial fibrillation (AF). Enlarged left atrium (LA) is considered to be an independent risk factor for newly diagnosed AF. We investigated the risk factors for predicting the stroke recurrence in NSAT patients. In total, 252 patients (114 women, mean 70 ± 11 years) with acute ischemic stroke and documented NSAT in 24-hour Holter monitoring were enrolled and followed. All patients underwent echo-Doppler evaluations. During a mean follow-up period of 35 ± 31 months, the stroke recurrence rate was 11.1% (28 of 252). The patients with recurrence (n = 28) had higher left atrium volume index (LAVI, P < .001) and higher E/e' (P = .028) compared with those without recurrence (n = 224). On the Kaplan-Meier survival analysis, stroke recurrence rate was significantly higher in patients with enlarged LA (LAVI >28 mm3/m2; P < .001 by the log-rank test), and it remained significant in multivariate analysis (hazard ratio, 1.154; 95% confidence interval [CI], 1.099-1.212, P < .001). In patients with acute ischemic stroke and NSAT, enlarged LA predicts an increased risk of stroke recurrence. This study supports the necessity of prolonged rhythm monitoring in stroke patients with NSAT and enlarged LA to detect undiagnosed AF and consequently considering anticoagulation therapy. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.
    No preview · Article · Aug 2015 · Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association
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    ABSTRACT: Fluid-attenuated inversion recovery (FLAIR) hyperintense vessels (FHVs) have been used to assess leptomeningeal collateral flow in acute ischemic stroke. However, prior FHVs studies showed inconsistent results, which may be ascribable to different magnetic resonance (MR) parameters used. To evaluate whether FHVs could be influenced by varying MR parameters and flow velocities, using a flow phantom. A total of 512 sets of FLAIRs were performed with varying parameters and flow velocities, using a flow phantom. Flow phantom was manufactured with 3.5% agarose solution, an 8-mm inner diameter silicone tube and non-pulsatile pump. Varying MR parameters were repetition time (TR)/inversion time (TI), echo time (TE), flip angle (FA) of refocusing pulse, and periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER). The signal intensity of flow were measured and regarded as the degree of FHVs. Simple and multiple linear regression analyses were applied to evaluate the association between the degree of FHVs and varying MR parameters as well as flow velocities. On univariate analysis, PROPELLER technique (R(2 )= 0.448) demonstrated strongest correlation with the degree of FHV, followed by flow velocities (R(2 )= 0.204), FA (R(2 )= 0.126), and TE (R(2 )= 0.031), whereas TR/TI showed no significant correlations. On multivariate analysis, TE, FA, PROPELLER technique, and flow velocities were independent factors influencing the degree of FHVs (<0.001). Flow velocities, FA of refocusing pulse, TE, and PROPELLER technique significantly affected the degree of FHVs. Optimized MR parameters should be used consistently in future studies, which may provide more reliable results. © The Foundation Acta Radiologica 2015.
    No preview · Article · Jun 2015 · Acta Radiologica
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    ABSTRACT: There are two established surgical treatment options for carotid artery stenosis. Carotid endarterectomy (CEA) has been accepted as a gold standard for surgical treatment while carotid artery stenting (CAS) has recently become an alternative option. Each treatment option has advantages and disadvantages for the treatment outcomes. We propose a protocol for selection of a proper surgical treatment option for carotid artery stenosis. A total of 192 published articles on management of carotid artery stenosis were reviewed. Preoperatively considerable factors which had been repeatedly noted in those articles for the risk/benefits of CEA or CAS were selected. According to those factors, a protocol with four categories was established. CEA or CAS is indicated when the patient has a symptomatic stenosis ≥ 50%, or when the patient has an asymptomatic stenosis ≥ 80%. Each treatment option has absolute indications and favorable indications. Each absolute indication is scored with three points, and each favorable indication, one point. Based on the highest scores, a proper treatment option (CEA or CAS) is selected. We have been treating patients according to this protocol and evaluating the outcomes of our protocol-based decision because this protocol might be helpful in assessment of risk/benefit for selection of a proper surgical treatment option in patients with carotid artery stenosis.
    Full-text · Article · Jun 2015
  • Ji Hwa Kim · Kyung Jin Roh · Sang Hyun Suh · Kyung-Yul Lee
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    ABSTRACT: Bilateral deafness is a rare but possible symptom of vertebrobasilar ischemia. We report a case of sudden bilateral sensorineural hearing loss caused by bilateral vertebral artery (VA) occlusion which dramatically improved after stenting. A 54-year-old man was admitted with sudden onset of bilateral deafness, vertigo, and drowsy mental status. Brain diffusion-weighted MRI showed acute infarction involving both the posterior inferior cerebellar artery and left posterior cerebral artery territory. Cerebral angiography showed bilateral distal VA occlusion, and emergency intracranial stenting was performed in the left VA. After reperfusion therapy his symptoms gradually improved, including hearing impairment. Endovascular stenting may be helpful in a patient with sudden deafness caused by bilateral VA occlusion. 2015 BMJ Publishing Group Ltd.
    No preview · Article · Feb 2015 · Journal of Neurointerventional Surgery
  • Han-Kyeol Kim · Seung-Ha Lee · Ji Hwa Kim · Kyung-Yul Lee

    No preview · Article · Dec 2014
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    Cheolsoo Han · Yeo-Jin Oh · Ji Hwa Kim · Kyung-yul Lee

    Preview · Article · Dec 2014
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    Kwon-Duk Seo · Kyung-Yul Lee · Byung Moon Kim · Sang Hyun Suh
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    ABSTRACT: We report a case of delayed cerebral infarction due to stent longitudinal folding deformation following carotid artery stenting using a self-expandable stent with an open-cell design. The stented segment of the left common carotid artery was divided into two different lumens by this folding deformation, and the separated lumens became restricted with in-stent thrombosis. Although no established method of managing this rare complication exists, a conservative approach was taken with administration of anticoagulant and dual antiplatelet therapy. No neurological symptoms were observed during several months of clinical follow-up after discharge.
    Preview · Article · Nov 2014 · Korean journal of radiology: official journal of the Korean Radiological Society
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    ABSTRACT: Background: The Effect of Cilostazol in Acute Lacunar Infarction Based on Pulsatility Index of the Transcranial Doppler (ECLIPse) study showed a significant decrease in the transcranial Doppler (TCD) pulsatility index (PI) with cilostazol treatment at 90 days after acute lacunar infarction. The aim of the present study was to perform a subgroup analysis of the ECLIPse study in order to explore the effect of cilostazol in acute lacunar infarction based on cerebral white matter hyperintensities (WMH) volume.
    No preview · Article · Oct 2014 · Cerebrovascular Diseases
  • Kyung-Yul Lee · Sung Jun Ahn · Ji Hwa Kim · Sang Won Han

    No preview · Article · Sep 2014 · Cerebrovascular Diseases
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    ABSTRACT: Clopidogrel is metabolized by the hepatic cytochrome P450 (CYP) system into its active thiol metabolite. CYP3A4 is involved in the metabolism of both clopidogrel and dihydropyridine calcium channel blockers (CCBs). A few reports have suggested an inhibitory interaction between CCBs and clopidogrel. Accordingly, the aim of this study was to determine the effect of CCBs on the antiplatelet activity of clopidogrel by serial P2Y12 reaction unit (PRU) measurements. We assessed changes in antiplatelet activity in patients receiving both clopidogrel and CCBs for at least 2 months prior to enrollment in the study. The antiplatelet activity of clopidogrel was measured by VerifyNow P2Y12 assay in the same patient while medicated with CCBs and at 8 weeks after discontinuation of CCBs. After discontinuation of the CCBs, angiotensin receptor blockers were newly administered to the patients or dosed up for control of blood pressure. Thirty patients finished this study. PRU significantly decreased after discontinuation of CCBs (238.1±74.1 vs. 215.0±69.3; p=0.001). Of the 11 patients with high post-treatment platelet reactivity to clopidogrel (PRU≥275), PRU decreased in nine patients, decreasing below the cut-off value in seven of these nine patients after 8 weeks. Decrease in PRU was not related to CYP2C19 genotype. CCBs inhibit the antiplatelet activity of clopidogrel.
    Preview · Article · May 2014 · Yonsei medical journal
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    ABSTRACT: Background: The purpose of this study is to compare the patterns of voiding dysfunction according to the locations of brainstem lesions. Methods: Between November 2008 and December 2011, a total of 30 patients participated in this study. All 30 subjects, consisting of 16 men and 14 women, aged between 41 and 82 years (mean age, 63.0±11.0 years) underwent a urodynamic study within 7 days after the onset of a stroke. Results: Twenty-one (70%) patients had a pontine lesion and 9 (30%) had a medullary lesion. Fourteen of these patients (46.7%) had bladder storage disorder, 7 patients (23.3%) had bladder emptying disorder, and 9 patients (30%) had a normal report. Five of the patients who had a medullary lesion (55.6%) had bladder emptying disorder, whereas only 2 patients who had a pontine lesion (9.5%) had bladder emptying disorder. Thirteen patients who had a pontine lesion (61.9%) showed bladder storage disorder. Discussion: The descending pathway from the midbrain tegmentum is inhibitory, and the pathway from the pontine tegmentum is stimulatory. Because of their location pontine lesions could disrupt the descending fibers of the midbrain tegmentum and medullary lesions could disrupt the descending fibers of the pontine tegmentum.
    Full-text · Article · Sep 2013 · European Neurology
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    ABSTRACT: The purpose of this study is to present our preliminary experience of the temporary endovascular bypass (TEB) technique using an Enterprise stent for recanalization of acute intracranial artery (IA) occlusion. Patients treated by TEB were enrolled in this retrospective study from January 2009 to May 2010. All the procedures consist of temporary partial deployment and subsequent retrieval of Enterprise stent, supplemented by intra-arterial infusion of urokinase (UK) and/or tirofiban. According to the thrombolysis in cerebral infarction (TICI) classification, recanalization was evaluated with initial and postprocedural angiography. Safety was evaluated related to the procedure and clinical outcomes were assessed by National Institute of Health Stroke Scale (NIHSS) score at discharge and modified Rankin scale (mRS) score at 3 months. Eleven patients (median NIHSS 12.8, mean age 61.6 years, male: female = 8:3) with acute IA occlusion were treated with TEB. All the patients presented with TICI 0, and the occluded vessel was the middle cerebral artery (n=7), the basilar artery (n=1), and the distal ICA occlusion (n = 3). IV infusion of tissue plasminogen activator (tPA) was done in 4 patients and mechanical thrombolysis with intra-arterial UK was performed in 9. Recanalization was achieved in 73% (8 patients; TICI ≥ 2). There were no procedure-related complications except for two asymptomatic intracranial hemorrhages. Improvement (≥ 4 points on the NIHSS) and good outcome (mRS ≤2) after 90 days was shown in six patients (55%). One patient died 6 days after procedure. TEB may be a valuable treatment option in acute thromboembolic IA occlusion without stent implantation.
    Full-text · Article · Sep 2013
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    ABSTRACT: Fluid-attenuated inversion recovery hyperintense vessels (FHVs) are known to reflect stagnant or slow blood flow within the cerebral artery. FHVs are frequently observed in patients with acute cerebral infarction accompanied by arterial occlusion or significant stenosis of the anterior cerebral circulation. However, FHVs have not been studied in the context of posterior cerebral circulation. Thus, we investigated the prevalence of FHVs and its clinical significance in patients with acute posterior cerebral artery (PCA) territory infarction. In this retrospective study, consecutive patients with PCA territory infarction who underwent MRI within 1 week after symptom onset were enrolled. Two neurologists who were blinded to the angiographic findings read the images and determined the presence of FHVs. Afterwards, FHVs were graded according to the extent (subtle or prominent) and location (proximal or distal) of the hyperintense vessels. Neurologic deficits of the patients were assessed by the National Institutes of Health Stroke Scale (NIHSS) upon admission and after 5 days. The clinical outcome between patient groups based on FHVs grading was compared using the NIHSS. Among the patients with PCA occlusion, infarction volume on the diffusion-weighted image was compared between the two groups with and without distal FHVs. FHVs were observed in 25 of the 87 patients (28.7%) with PCA territory infarction and in 65.7% of the 35 patients with significant arterial stenosis (10 patients) or occlusion (25 patients) in the posterior cerebral circulation. Among the 18 patients with PCA occlusion, the NIHSS score was significantly improved in patients with distal FHVs compared to the others (2.00 ± 2.18 vs. 0.56 ± 1.01, p = 0.04). The infarction volume was smaller in the distal FHV group than in the others (8.3 ± 8.7 vs. 16.8 ± 17.6 ml), but the difference was not statistically significant. FHVs are detected in patients with PCA territory infarction, especially in those with an occlusive lesion in the PCA. FHVs can be used as an imaging marker of PCA occlusion. Although this study showed a better clinical improvement in patients with distal FHVs, further study is needed to elucidate the clinical meaning of FHVs in PCA infarction.
    Preview · Article · Apr 2013
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    ABSTRACT: Purpose Cerebral ischemic lesions are frequently observed after carotid artery stenting (CAS), and anti-platelet agents are used to prevent stent thrombosis and peri-procedural complications. However, despite the premedication, cerebral ischemic lesions are observed, suggesting that they may rather be related to anti-platelet resistance. We, therefore, investigated the effects of anti-platelet resistance on the development of cerebral ischemic lesions after CAS. Materials and Methods We retrospectively reviewed patients who received CAS and selected patients for whom brain MRI was performed within 24 hours after CAS and for whom anti-platelet resistance was checked. Anti-platelet resistance was examined by the VerifyNow system. We analyzed the correlation between anti-platelet resistance and cerebral ischemic lesions detected on follow-up MRI. Results Among 76 patients, 45 (59.2%) developed new ischemic lesions after CAS. Twelve (15.8%) patients showed aspirin resistance and 50 (65.8%) patients showed clopidogrel resistance. Patients with a new ischemic lesion demonstrated a significantly greater frequency of clopidogrel resistance than those who had no new ischemic lesion (82.2% versus 41.9%, p=0.001). The frequency of aspirin resistance was not significantly different between the groups of patients with and without new ischemic lesions (20.0% versus 9.7%, p=0.340). In multivariate analysis, clopidogrel resistance was a significant risk factor for post-procedural cerebral ischemia. Conclusion Anti-platelet resistance can be used to predict new ischemic lesions after CAS. Anti-platelet resistance should be evaluated in all patients prior to CAS to prevent ischemic complications related to CAS.
    Preview · Article · Mar 2013 · Yonsei medical journal
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    ABSTRACT: A healthy, 66-year-old, right-handed man was admitted to our university hospital and diagnosed with herpes zoster ophthalmicus (HZO). After 4weeks, he complained of hemichorea on his left side. Brain MRI showed a focal hemorrhage in the right subthalamic area. No evidence of aneurysmal lesion or cerebral angiitis was observed on cerebral angiography.
    Full-text · Article · Feb 2013 · Journal of Clinical Neuroscience
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    ABSTRACT: Background: This study is intended to evaluate the propensities of cilostazol to reduce the pulsatility index (PI) in patients with acute lacunar infarction using the serial transcranial Doppler (TCD) examinations. Methods: In a multicenter, randomized, double-blind, placebo-controlled trial, patients were randomly assigned to receive either placebo or 100 mg cilostazol twice a day as well as aspirin 100 mg a day. The primary outcomes were the changes of middle cerebral artery (MCA) and basilar artery (BA) PIs at 14 and 90 days from the baseline TCD study. This study is registered with ClinicalTrials.gov (NCT00741286). Results: Trial medication was given to 203 patients, with 100 receiving cilostazol and 103 receiving placebo, and 164 were included in the per-protocol analysis of the primary outcome. Results from the linear mixed model showed that significant effects were obtained for time-by-group interactions (p = 0.008 in right MCA, p = 0.015 in left MCA, p = 0.002 in BA), suggesting that changes of PIs from the baseline to the 90-day study were different across the groups. Conclusions: Cilostazol further decreased TCD PIs at 90 days from baseline compared to placebo in acute lacunar infarction. This result may be related to pleiotropic effects, such as vasodilation, beyond its antiplatelet activity.
    No preview · Article · Nov 2012 · European Neurology
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    Tae-Jin Song · Young-Chul Choi · Kyung-Yul Lee · Won-Joo Kim
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    ABSTRACT: Purpose Late diagnosis and treatment lead to high mortality and poor prognosis in tuberculous meningitis (TbM). A rapid and accurate diagnosis is necessary for a good prognosis. Neuron-specific enolase (NSE) has been investigated as a biochemical marker of nervous tissue damage. In the present study, the usefulness of NSE was evaluated, and a cut-off value for the differential diagnosis of TbM was proposed. Materials and Methods Patient charts were reviewed for levels of serum and cerebrospinal fluid (CSF) NSE, obtained from a diagnostic CSF study of samples in age- and gender-matched TbM (n=15), aseptic meningitis (n=28) and control (n=37) patients. Results CSF/serum NSE ratio was higher in the TbM group than those of the control and aseptic groups (p=0.001). In binary logistic regression, CSF white blood cell count and CSF/serum NSE ratio were significant factors for diagnosis of TbM. When the cut-off value of the CSF/serum NSE ratio was 1.21, the sensitivity was 86.7% and the specificity was 75.4%. Conclusion The CSF/serum NSE ratio could be a useful parameter for the early diagnosis of TbM. In addition, the authors of the present study suggest a cut-off value of 1.21 for CSF/serum NSE ratio.
    Preview · Article · Nov 2012 · Yonsei medical journal

Publication Stats

361 Citations
91.72 Total Impact Points

Institutions

  • 2008-2015
    • Yonsei University
      • Department of Radiology
      Sŏul, Seoul, South Korea
  • 2004-2015
    • Yonsei University Hospital
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2005
    • Korea Brain Research Institute
      Daikyū, Daegu, South Korea