Publications by authors named "Si Un Lee"

Article Synopsis
  • - This study examines the link between Moyamoya disease (MMD) and open-angle glaucoma (OAG) using data from 36,432 MMD patients and 346,769 matched controls in South Korea from 2002 to 2022.
  • - Researchers used statistical models to find that patients with MMD had a significantly higher risk of developing OAG compared to those without MMD, with a hazard ratio of 1.26.
  • - The cumulative incidence of OAG was 3.7% in the MMD group versus 2.9% in the control group, indicating that MMD patients consistently faced a greater risk of developing OAG throughout the study.
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Background And Purpose: The immune response following aneurysmal subarachnoid hemorrhage (aSAH) can exacerbate secondary brain injury and impact clinical outcomes. As the immune response after aSAH is a dynamic process, we aim to track and characterize immune cell trajectories over time to identify patterns associated with various clinical outcomes.

Methods: In this retrospective single-center study of patients with aSAH, we analyzed immune cell count trajectories, including neutrophil, monocyte, and lymphocyte counts, collected from day 1 to day 14.

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Article Synopsis
  • - The study aimed to explore the risk of retinal vascular occlusion in patients with Moyamoya disease (MMD) using data from a large national health insurance database in Korea.
  • - Researchers analyzed over 34,000 newly diagnosed MMD patients and matched them with control subjects to investigate the occurrence of retinal vascular occlusion events through specific diagnostic codes.
  • - Results indicated that MMD patients had a significantly higher risk of developing retinal vascular occlusion, with particular concern for central retinal artery occlusion, highlighting MMD as a notable risk factor for this condition.
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The safety and efficacy of coronavirus disease 2019 (COVID-19) vaccination in patients diagnosed with Moyamoya disease (MMD) have not been established. Using National Health Insurance Service data, this study analyzed the occurrence of stroke-related events and mortality following COVID-19 vaccination among patients diagnosed with MMD from 2008 to 2020. Among 10,297 MMD patients, 296 (2.

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Background And Purpose: Swelling of the salivary glands, known as contrast-induced sialadenitis (CIS), is an adverse reaction to iodide contrast agents. However, the incidence and risk factors of CIS after therapeutic neuroendovascular procedures have not yet been established.

Materials And Methods: Demographic and procedural factors that may influence the development of CIS were retrospectively analyzed to identify the incidence and risk factors of this condition.

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Objective: This study was designed to identify predictive factors associated with substantial contralateral progression in adult patients with bilateral nonhemorrhagic moyamoya disease (MMD) who undergo revascularization surgery (RS) on one hemisphere.

Methods: The authors retrospectively analyzed 174 contralateral hemispheres of patients with bilateral nonhemorrhagic MMD (non-hMMD) who underwent RS on one side. The primary endpoint was defined as substantial contralateral progression requiring additional RS 6 months after the initial RS.

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Background: To analyze the outcomes of clipping and coiling for ruptured intracranial aneurysms (RIAs) based on data from the National Health Insurance Service in South Korea, with a focus on variations according to region and hospital size.

Methods: This study analyzed the one-year mortality rates for patients with RIAs who underwent clipping or coiling in 2018. Coiling was further categorized into non-stent assisted coiling (NSAC) and stent assisted coiling (SAC).

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Objective: The aim of this study was to identify predictive factors of postoperative cerebral infarction (PostCI) following combined bypass (CB) surgery in adult patients with moyamoya disease (MMD) using quantitative parameters from the rapid processing of perfusion and diffusion (RAPID) perfusion CT (PCT) software.

Methods: The authors retrospectively reviewed 276 total hemispheres in patients with MMD who underwent CB. Preoperative volumes of time-to-maximum (Tmax) > 4 sec and > 6 sec were obtained from the RAPID analysis of PCT.

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Objective: To analyze the relationship between in-stent restenosis (ISR) following carotid artery stenting (CAS) and platelet clopidogrel reactivity confirmed by the P2Y12 reaction unit (PRU) and inhibition rate (IR).

Methods: We retrospectively analyzed 171 patients who underwent CAS with extracranial carotid stenosis from January 2016 to December 2019. Dual antiplatelet therapy with 100 mg aspirin and 75 mg clopidogrel was started ≥5 days before CAS.

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Background: There have been few reports on the preventative value of intensive blood pressure (BP) management for stroke since the American College of Cardiology/American Heart Association (ACC/AHA) announced the new criteria for hypertension (HTN) in 2017. This study aimed to identify optimal BP for prevention of stroke in healthy adults under 65 years.

Methods: We conducted a 10-year observational study on the risk of stroke, subclassified as hemorrhagic stroke (HS) or ischemic stroke (IS), according to BP categories (low-normal BP, high-normal BP, elevated BP, stage 1 HTN, and stage 2 HTN) using the National Health Insurance Service Database.

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To investigate the association between chemical markers (triglyceride, C-reactive protein (CRP), and inflammation markers) and perfusion markers (relative cerebral vascular reserve (rCVR)) with moyamoya disease progression and complication types. A total of 314 patients diagnosed with moyamoya disease were included. Triglyceride and CRP levels were assessed and categorized based on Korean guidelines for dyslipidemia and CDC/AHA guidelines, respectively.

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Background: We sought to determine the utility of intracranial-to-intracranial bypass (IIB) surgery and the available bypass options for complex cases.

Methods: A total of 18 IIB cases were included. Each case was classified as IIB with or without an interposition graft.

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Article Synopsis
  • - The study investigates the relationship between blood pressure (BP) management and the risk of hemorrhagic stroke (HS), focusing on new hypertension guidelines established in 2017 by American health organizations.
  • - Over a decade, researchers analyzed data from nearly one million participants to identify which BP categories are linked to increased risks of intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH).
  • - Findings indicate that adults under 65 with stage 1 hypertension experience a significant rise in HS risk, suggesting that effective BP management is crucial for prevention in this population.
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Objective: To analyze the outcomes of coil embolization (CE) for unruptured intracranial aneurysm (UIA) according to region and hospital size based on National Health Insurance Service data in South Korea.

Methods: The incidence of complications, including intracranial hemorrhage (ICRH) and cerebral infarction (CI), occurring within 3 months and the 1-year mortality rates in UIA patients who underwent CE in 2018 were analyzed. Hospitals were classified as tertiary referral general hospitals (TRGHs), general hospitals (GHs) or semigeneral hospitals (sGHs) according to their size, and the administrative districts of South Korea were divided into 15 regions.

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Background: Subarachnoid hemorrhage (SAH) patients have oxidative stress results in inflammation, tissue degeneration and neuronal damage. These deleterious effects cause aggravation of the perihematomal edema (PHE), vasospasm, and even hydrocephalus. We hypothesized that antioxidants may have a neuroprotective role in acute aneurysmal SAH (aSAH) patients.

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Article Synopsis
  • - The study investigated the effectiveness of nonemergent extracranial-to-intracranial bypass (EIB) in 86 patients with symptomatic chronic large artery atherosclerotic stenosis, using computed tomography perfusion (CTP) data from preoperative, immediate postoperative, and 6 months postoperative periods.
  • - Results revealed significant reductions in time-to-maximum (Tmax) volumes after EIB, indicating improved blood flow, with strong correlations between postoperative blood flow and CTP parameters.
  • - The incidence of recurrent cerebral infarction was low at 4.7%, and there were no major complications leading to permanent neurological impairment, suggesting EIB is a viable treatment for patients with hemodynamically compromised large artery
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Objective: The aim of this study was to identify predictive factors for hemorrhagic cerebral hyperperfusion syndrome (hCHS) after direct bypass surgery in adult nonhemorrhagic moyamoya disease (non-hMMD) using quantitative parameters on rapid processing of perfusion and diffusion (RAPID) perfusion CT software.

Methods: A total of 277 hemispheres in 223 patients with non-hMMD who underwent combined bypass were retrospectively reviewed. Preoperative volumes of time to maximum (Tmax) > 4 seconds and > 6 seconds were obtained from RAPID analysis of perfusion CT.

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This study aimed to demonstrate the effectiveness of urgent extracranial-to-intracranial bypass (EIB) in acute ischemic stroke (AIS) through quantitative analysis of computed tomography perfusion (CTP) results using RAPID software. We retrospectively analyzed 41 patients who underwent urgent EIB for AIS under strict operation criteria. The quantitative data from CTP images were reconstructed to analyze changes in pre- and postoperative perfusion status in terms of objective numerical values using RAPID software.

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Objective: The objective of the study was to assess the esthetic efficacy of acellular dermal matrix (ADM) implantation to prevent frontotemporal depression (FTD) following minipterional craniotomy (MPT) to clip unruptured intracranial aneurysms.

Methods: We retrospectively compared the incidence of FTD in 100 patients treated without ADM from March to July 2019 and 100 patients treated with ADM from August to December 2019. ADM was implanted in the interfascial layer to cover the temporalis muscle.

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Objective: The treatment of multiple intracranial aneurysms (MIAs) involves various modalities and sometimes requires staged operations. This study aimed to prove the efficacy and safety of one-stage multiple craniotomies (OSMC) for multiple cerebral aneurysms.

Methods: We retrospectively reviewed the medical records of the patients who underwent treatment for intracranial aneurysms between May 2003 and April 2020.

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Article Synopsis
  • Nontraumatic subdural hematoma (SDH) is often linked to cerebrospinal fluid (CSF) leakage, which is typically diagnosed through invasive methods, but this study shows that heavily T2-weighted magnetic resonance myelography (HT2W-MRM) is a safe and effective imaging alternative.
  • In the study, 40 patients were analyzed, revealing that 55% had CSF leakage, and most showed improvement in their modified Rankin Scale (mRS) scores after treatment.
  • The findings indicate that HT2W-MRM should be considered a primary imaging tool for diagnosing CSF leakage in nontraumatic SDH patients, potentially leading to changes in diagnosis and treatment approaches.
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Background: Noncontrast computed tomography (NCCT) markers for hematoma expansion (HE) in intracerebral hemorrhage (ICH) are difficult to be found in small ICHs, of which can also expand. We aimed to investigate whether there were size-related differences in the prevalence of NCCT markers and their association with HE.

Methods: This retrospective analysis of prospectively collected stroke registry included 267 consecutive patients with ICH who underwent baseline NCCT within 12 h of onset.

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Article Synopsis
  • - The study investigates the role of the inhibition rate in the VerifyNow test to assess thromboembolic risks during coil embolization for unruptured intracranial aneurysms, particularly for patients with a P2Y12 reaction unit (PRU) of 220 or lower.
  • - Analyzed 954 patients and found that thromboembolic events occurred in 11 patients (1.08%) within 30 days post-procedure; the area under the ROC curve was 0.83, indicating good predictive ability.
  • - The optimal cut-off for the inhibition rate was established at 22.0%, demonstrating its significance in identifying patients at high risk for thromboembolic events with PRU levels at or below
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