Delayed Lesions on Diffusion-Weighted Imaging in Initially Lesion-Negative Stroke Patients.

Background And Purpose: Lesions on diffusion-weighted imaging (DWI) occasionally appear on follow-up magnetic resonance imaging (MRI) among initially DWI-negative but clinically suspicious stroke patients. We established the prevalence of positive conversion in DWI-negative stroke and determined the clinical factors associated with it.

Methods: This retrospective, observational, single-center study included 5,271 patients hospitalized due to stroke/transient ischemic attack (TIA) in a single university hospital during 2010 to 2017.

Relationship between blood pressure and outcome changes over time in acute ischemic stroke.

Objective: To evaluate whether the relationship between systolic blood pressure (SBP) and stroke outcome varies during the acute stage of ischemic stroke as a function of the elapsed time after stroke onset.

Methods: Patients who were hospitalized due to ischemic stroke within 6 hours of onset were retrospectively analyzed. SBP data were collected at 8 time points (1, 2, 4, 8, 16, 24, 48, and 72 hours after onset).

Blood pressure variability in subacute stage and risk of major vascular events in ischemic stroke survivors.

Background: We aimed to investigate whether blood pressure (BP) in the subacute stage of ischemic stroke affects subsequent vascular events after acute ischemic stroke.

Methods: From a prospective stroke registry database, consecutive ischemic stroke patients arriving within 48 h of onset were identified. The mean and SD of SBP per patient (SBPmean and SBPSD) in the subacute stage (from 72 h of onset to discharge), were calculated.

Tenacity of Collateral Perfusion in Proximal Cerebral Arterial Occlusions 6-12 h after Onset.

Background: Clinical trials have shown that benefits of endovascular recanalization (EVT) for acute ischemic stroke patients with sizable penumbral tissues seems plausible even beyond 6 h after their last seen normal (LSN). Persistency of ischemic penumbra remains unclear in delayed periods.

Methods: From a prospective stroke registry database, we identified 111 acute ischemic stroke patients who had internal carotid artery or middle cerebral artery occlusion with baseline National Institutes of Health Stroke Scale scores ≥6 points and arrived 6-12 h after LSN.

Posttreatment National Institutes of Health Stroke Scale Is Superior to the Initial Score or Thrombolysis in Cerebral Ischemia for 3-Month Outcome.

Background And Purpose: The majority of ischemic stroke patients receiving endovascular recanalization therapy (EVT) experience variable changes of neurological severities during the hyperacute period. We hypothesized that the National Institutes of Health Stroke Scale (NIHSS) score after EVT is a better prognostic factor compared with the initial NIHSS score or revascularization status.

Methods: We identified 566 stroke patients who received EVT at Seoul National University Bundang Hospital between April 2008 and December 2015.

The Role of the Signal Intensity Ratio on Fluid-Attenuated Inversion Recovery in Stroke Patients Achieving Successful Recanalization with Endovascular Treatment.

Background: This study aimed to investigate whether fluid-attenuated inversion recovery (FLAIR) imaging hyperintensity can be used as a surrogate marker for the severity of ischemic insult and predict lesion growth.

Methods: Based on a prospective stroke registry database, we identified patients with ischemic stroke who were treated with endovascular treatment (EVT) within 8 hours of onset and achieved successful recanalization (modified thrombolysis in cerebral infarction ≥2B). FLAIR hyperintensity was measured using the signal intensity ratio (SIR), defined as the mean SIR of diffusion-restricted lesions to the corresponding areas in the contralateral hemisphere.

CT Angiography of Collateral Vessels and Outcomes in Endovascular-Treated Acute Ischemic Stroke Patients.

Background And Purpose: Measuring the extent of the collateral blood vessels using computed tomography (CT) angiography source images may promote tissue survival and functional gain in acute ischemic stroke patients who are candidates for endovascular recanalization treatment.

Methods: Of 5,558 acute stroke patients registered in a prospective clinical stroke registry, 104 met the selection criteria of endovascular recanalization treatment for internal cerebral artery or middle cerebral artery main-stem (M1) occlusions and presented for treatment ≤4 hours after the event. Using CT angiography source images, two independent and blinded reviewers measured the extent of collateral circulations at four regions, with good interrater reliability.

Stroke outcomes with use of antithrombotics within 24 hours after recanalization treatment.

Objective: To compare clinical outcomes of patients who received early initiation (<24 hours) of antithrombotics with those who received standard management (antithrombotics administered ≥24 hours).

Methods: A total of 712 patients who had an acute ischemic stroke and underwent IV or endovascular (intra-arterial [IA]) recanalization between July 2007 and March 2015 were selected from a prospective clinical registry. Antithrombotics were initiated by an individual clinical decision.

Left Ventricular Diastolic Dysfunction in Ischemic Stroke: Functional and Vascular Outcomes.

Background And Purpose: Left ventricular (LV) diastolic dysfunction, developed in relation to myocardial dysfunction and remodeling, is documented in 15%-25% of the population. However, its role in functional recovery and recurrent vascular events after acute ischemic stroke has not been thoroughly investigated.

Methods: In this retrospective observational study, we identified 2,827 ischemic stroke cases with adequate echocardiographic evaluations to assess LV diastolic dysfunction within 1 month after the index stroke.

A Simple Geometric Assessment of Perfusion Lesion Volume at Hyperacute Stage of Ischemic Stroke in Patients with Symptomatic Steno-Occlusion of Major Cerebral Arteries and Risk of Subsequent Cerebral Ischemic Events.

Our objective is to elucidate the association of baseline perfusion lesion volume on perfusion-weighted magnetic resonance imaging (PWI) obtained at hyperacute stage of ischemic stroke with subsequent cerebral ischemic events (SIEs) in patients with symptomatic steno-occlusion of major cerebral arteries. Using a prospective stroke registry database, patients arriving within 24 hours of onset with symptomatic steno-occlusion of major supratentorial cerebral arteries were identified. On baseline PWI, time-to-peak lesion volume (TTP-LV) was determined by a simple geometric method and dichotomized into the highest tertile (large) and the other tertiles (small to medium) according to the vascular territory of occluded arteries.

Blood pressure variability and the development of early neurological deterioration following acute ischemic stroke.

Objectives: Early neurological deterioration (END) is a common condition associated with poor outcome after acute ischemic stroke. We studied association between blood pressure (BP) variability and development of END.

Methods: In this retrospective observational study, we studied a consecutive series of patients hospitalized for acute ischemic stroke within 24 h of onset.

Neuroimaging markers for early neurologic deterioration in single small subcortical infarction.

Background And Purpose: Early neurological deterioration (END) occurs in ≥20% of single small subcortical infarctions (SSSIs; axial diameter ≤20 mm in the perforator territories) and deters functional recovery. Both microvasculopathies and atherosclerosis have been proposed to independently contribute to the occurrence of END in SSSI cases. We hypothesized that the occurrence of END in SSSIs differs according to the pathological process.

Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification and vascular territory of ischemic stroke lesions diagnosed by diffusion-weighted imaging.

Background: The association between the location and the mechanism of a stroke lesion remains unclear. A diffusion-weighted imaging study may help resolve this lack of clarity.

Methods And Results: We studied a consecutive series of 2702 acute ischemic stroke patients whose stroke lesions were confirmed by diffusion-weighted imaging and who underwent a thorough etiological investigation.

Genetic analysis of human parainfluenza viruses circulating in Korea, 2006.

Human parainfluenza viruses (HPIV) are important causes of respiratory tract infections in young children. To characterize the molecular epidemiology of an HPIV outbreak occurring in Korea during 2006, genetic analysis of 269 cell culture isolates from HPIV-infected children, was conducted using nested reverse transcription-PCR (RT-PCR). HPIV-1 was detected in 70.

Impact of both ends of the hemoglobin range on clinical outcomes in acute ischemic stroke.

Background And Purpose: Although both ends of the hemoglobin range may negatively influence clinical outcomes in acute ischemic stroke, most studies have examined the linear relationship or focused on the lower end of the range. Furthermore, it is unclear whether hemoglobin concentrations at different time points during hospitalization correlate with clinical outcomes in the same manner.

Methods: We identified 2681 consecutive patients with acute ischemic stroke from a prospective stroke registry database and grouped them into hemoglobin concentration quintiles using the following 5 indices: initial, nadir, time-averaged, discharge hemoglobin, and hemoglobin drop.

Validation of FLAIR hyperintense lesions as imaging biomarkers to predict the outcome of acute stroke after intra-arterial thrombolysis following intravenous tissue plasminogen activator.

Background: Intravenous tissue plasminogen activator (tPA) given within 4.5 h of symptom onset is accepted as the standard treatment of ischemic stroke. Persistent occlusion of cerebral arteries despite intravenous thrombolysis and unremitting neurologic deficits lead us to consider additional intra-arterial approaches.

Effect of blood pressure on 3-month functional outcome in the subacute stage of ischemic stroke.

Objective: We aimed to study various measures of blood pressure (BP) in the subacute phase of ischemic stroke to determine whether any of them predicted clinical outcome.

Methods: In this retrospective observational study, a consecutive series of patients hospitalized for ischemic stroke within 48 hours of onset were enrolled. The subacute stage of stroke was defined as the time period from 72 hours of symptom onset to discharge or transfer.

Is aortic atherothrombotic disease detected using multidetector-row CT associated with an increased risk of early ischemic lesion recurrence after acute ischemic stroke?

Background And Purpose: Multidetector-row CT (MDCT) is emerging as a new tool for diagnosing aortic atherothrombotic disease (AAD). We elucidated whether MDCT-detected AAD is associated with an increased risk of early ischemic lesion recurrence on diffusion-weighted MRI after ischemic stroke.

Methods: A consecutive series of patients with acute ischemic stroke confirmed using diffusion-weighted MRI who were hospitalized within 48 hours after symptom onset and underwent MDCT were identified in a prospective stroke registry database.

Selective and sensitive ratiometric detection of Hg(II) ions using a simple amino acid based sensor.

Synthesis of a novel pyrene derivative sensor (Py-Met) based on amino acid and its fluorescent behavior for Hg(II) in water was investigated. Upon Hg(II) binding, the Py-Met-bearing sulfonamide group exhibited a considerable excimer emission at 480 nm along with a decrease of monomer emission at 383 nm. Py-Met allows a selective and sensitive ratiometric detection of Hg(II) without any interference from other metal ions.

Burden of ischemic stroke in Korea: analysis of disability-adjusted life years lost.

Background And Purpose: Disability-adjusted life years (DALY), incorporating both disability and mortality, has been widely employed to measure regional and global burdens of stroke. Thus far, the DALY lost to stroke in a population has been estimated using only the crude population-level data; no previous study has incorporated refined data from stroke registries. The aim of this study was to integrate the stroke registry data and the population-level incidence data to project the nationwide DALY lost to ischemic stroke.

A methionine-based turn-on chemical sensor for selectively monitoring Hg2+ ions in 100% aqueous solution.

Dansyl-labeled methionine is synthesized by solid-phase synthesis, and found to be a highly sensitive and selective sensor for Hg(2+). The sensor sensitively detects Hg(2+) ions in aqueous solution by a turn-on response; however, the sensor detects Hg(2+) ions by a turn-off response in organic and mixed aqueous-organic solutions. We investigated the binding stoichiometry, binding constant, and binding mode of the sensor under various solvent conditions.

The significance of blood pressure variability for the development of hemorrhagic transformation in acute ischemic stroke.

Background And Purpose: Elevated blood pressure (BP) is commonly observed in acute ischemic stroke and is known to be associated with hemorrhagic transformation (HT). However, the effect of BP variability on the development of HT is not known well.

Methods: A consecutive series of patients with acute ischemic stroke, who were hospitalized within 24 hours of onset and showed no HT on initial gradient echo MRI, were enrolled in this study.

Differential effect of previous antiplatelet use on stroke severity according to stroke mechanism.

Background And Purpose: The effect of previous antiplatelet use on stroke severity is controversial. We assume that this controversy is attributable to its difference according to the stroke mechanism.

Methods: Using a prospective stroke registry, patients who were hospitalized because of ischemic stroke and had relevant lesions on MRI were selected.

Can early ischemic lesion recurrence on diffusion-weighted MRI affect functional outcome after acute ischemic stroke?

Background And Purpose: Ischemic lesion recurrence on diffusion-weighted imaging (DWI-LR) is a frequently observed phenomenon after acute ischemic stroke. However, no study has elucidated the impact of DWI-LR on functional outcome.

Methods: Among a consecutive series of patients who presented with focal symptoms or signs compatible with stroke within 48 hours from the onset over a 50-month period, those who had relevant ischemic lesions on initial DWI and underwent follow-up DWI within 14 days after the onset were enrolled in this study.