Acute Infarct Segmentation on Diffusion-Weighted Imaging Using Deep Learning Algorithm and RAPID MRI

Ryu Wi-Sun,Kang You-Ri,Noh Yoon-Gon,Park Jong-Hyeok,Kim Dongmin,Kim Byeong C.,Park Man-Seok,Kim Beom Joon,Kim Joon-Tae 대한뇌졸중학회 2023 Journal of stroke Vol.25 No.3

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Diastolic Dysfunction and Outcome in Acute Ischemic Stroke

Ryu, Wi-Sun,Park, Jun-Bean,Ko, Sang-Bae,Hwang, Seung-sik,Kim, Yong-Jin,Kim, Dong-Eog,Lee, Seung-Hoon,Yoon, Byung-Woo S. Karger AG 2016 Cerebrovascular Diseases Vol.41 No.3

<P>Background: Left ventricular diastolic dysfunction (DD) is associated with an increased mortality in general population and patients with myocardial infarct. In the present study, we investigated whether DD is associated with outcomes after ischemic stroke. Methods: Five hundred and three acute ischemic stroke patients with normal left ventricular ejection fraction (>= 50%) were retrospectively included. Echocardiography and tissue Doppler imaging were used to evaluate and grade diastolic function. Ordinal logistic and Cox regression analyses were used to examine relations between DD and modified Rankin Scale (mRS) score at 3 months and mortality after stroke, respectively. Results: Mean age was 67.2 +/- 11.8 years and 63% were men. Among parameters of diastolic function, early mitral inflow velocity/early diastolic mitral annulus velocity (E/e') was independently related with higher mRS score at 3 months and mortality after ischemic stroke. The highest quartile of E/e' (> 14) was independently associated with higher mRS score (adjusted OR 3.86, 95% CI 2.27-6.54) as well as with mortality (hazards ratio [HR] 2.87, 95% CI 1.17-7.04) as compared to the lowest quartile of E/e' (< 8.8). In addition, moderate-to-severe DD grade was related to higher mRS score (adjusted OR 2.41, 95% CI 1.15-5.06) and mortality (HR 6.63, 95% CI 1.80-24.43) compared to the normal diastolic function. Conclusion: In patients with ischemic stroke, DD is associated with functional outcome at 3 months and mortality. Our data suggest that more attention should be given to DD in patients with ischemic stroke. (C) 2016 S. Karger AG, Basel</P>

Grading and Interpretation of White Matter Hyperintensities Using Statistical Maps

Ryu, Wi-Sun,Woo, Sung-Ho,Schellingerhout, Dawid,Chung, Moo K.,Kim, Chi Kyung,Jang, Min Uk,Park, Kyoung-Jong,Hong, Keun-Sik,Jeong, Sang-Wuk,Na, Jeong-Yong,Cho, Ki-Hyun,Kim, Joon-Tae,Kim, Beom Joon,Han, American Heart Association, Inc. 2014 Stroke Vol.45 No.12

<P><B>Background and Purpose—</B></P><P>We aimed to generate rigorous graphical and statistical reference data based on volumetric measurements for assessing the relative severity of white matter hyperintensities (WMHs) in patients with stroke.</P><P><B>Methods—</B></P><P>We prospectively mapped WMHs from 2699 patients with first-ever ischemic stroke (mean age=66.8±13.0 years) enrolled consecutively from 11 nationwide stroke centers, from patient (fluid-attenuated-inversion-recovery) MRIs onto a standard brain template set. Using multivariable analyses, we assessed the impact of major (age/hypertension) and minor risk factors on WMH variability.</P><P><B>Results—</B></P><P>We have produced a large reference data library showing the location and quantity of WMHs as topographical frequency-volume maps. This easy-to-use graphical reference data set allows the quantitative estimation of the severity of WMH as a percentile rank score. For all patients (median age=69 years), multivariable analysis showed that age, hypertension, atrial fibrillation, and left ventricular hypertrophy were independently associated with increasing WMH (0–9.4%, median=0.6%, of the measured brain volume). For younger (≤69) hypertensives (n=819), age and left ventricular hypertrophy were positively associated with WMH. For older (≥70) hypertensives (n=944), age and cholesterol had positive relationships with WMH, whereas diabetes mellitus, hyperlipidemia, and atrial fibrillation had negative relationships with WMH. For younger nonhypertensives (n=578), age and diabetes mellitus were positively related to WMH. For older nonhypertensives (n=328), only age was positively associated with WMH.</P><P><B>Conclusions—</B></P><P>We have generated a novel graphical WMH grading (Kim statistical WMH scoring) system, correlated to risk factors and adjusted for age/hypertension. Further studies are required to confirm whether the combined data set allows grading of WMH burden in individual patients and a tailored patient-specific interpretation in ischemic stroke-related clinical practice.</P>

Body Mass Index, Initial Neurological Severity and Long-Term Mortality in Ischemic Stroke

Ryu, Wi-Sun,Lee, Seung-Hoon,Kim, Chi Kyung,Kim, Beom Joon,Yoon, Byung-Woo S. Karger AG 2011 Cerebrovascular Diseases Vol.32 No.2

<P>Abstract</P><P><I>Background:</I> Obesity is believed to increase the risks of ischemic stroke or coronary heart disease; however, regarding outcome after established vascular diseases, recent unexpected evidence has suggested that an increased body mass index (BMI) might have beneficial effects (obesity paradox). The aim of this study was to evaluate the independent association between BMI and long-term mortality after ischemic stroke. <I>Methods:</I> A total of 1,592 consecutive patients with ischemic stroke were prospectively included through our stroke cohort. In this study, the levels of BMI were classified based on guidelines for the Asian-Pacific population. Initial neurological severity was estimated by the National Institutes of Health Stroke Scale (NIHSS) score. Information on mortality was collected until the end of 2009, and the median follow-up period was 4 years. To examine the association between BMI and long-term mortality, we used Cox’s proportional regression analysis. <I>Results:</I> During follow-up, 23% of patients died. Linear regression analysis showed that the level of BMI was inversely related to initial neurological severity (p = 0.002). In the model of adjustment of age and gender using Cox’s proportional regression analysis, this inverse trend was also significant (reference, normal weight; hazard ratio of underweight, 2.45; overweight, 0.77; obesity, 0.60). However, after adjustment of all covariates, including initial neurological severity, only the harmful effect of underweight remained significant (2.79; 95% CI, 1.92–4.05); however, beneficial effects of overweight and obesity did not. <I>Conclusion:</I> Our study showed that an independent association between BMI and long-term mortality after ischemic stroke was found only in underweight patients. The obesity paradox phenomenon seems to be limited, and might not be interpreted as a direct causal relationship due to a strong association with initial neurological severity.</P><P>Copyright © 2011 S. Karger AG, Basel</P>

Enterovirus 71 Infection with Central Nervous System Involvement, South Korea

Ryu, Wi-Sun,Kang, Byunghak,Hong, Jiyoung,Hwang, Seoyeon,Kim, Ahyoun,Kim, Jonghyun,Cheon, Doo-Sung Centers for Disease Control and Prevention 2010 Emerging infectious diseases Vol.16 No.11

<P>We assessed neurologic sequelae associated with an enterovirus 71 (EV71) outbreak in South Korea during 2009. Four of 94 patients had high signal intensities at brainstem or cerebellum on magnetic resonance imaging. Two patients died of cardiopulmonary collapse; 2 had severe neurologic sequelae. Severity and case-fatality rates may differ by EV71 genotype or subgenotype.</P>

Stroke outcomes are worse with larger leukoaraiosis volumes

Ryu, Wi-Sun,Woo, Sung-Ho,Schellingerhout, Dawid,Jang, Min Uk,Park, Kyoung-Jong,Hong, Keun-Sik,Jeong, Sang-Wuk,Na, Jeong-Yong,Cho, Ki-Hyun,Kim, Joon-Tae,Kim, Beom Joon,Han, Moon-Ku,Lee, Jun,Cha, Jae-Kw Oxford University Press 2017 Brain Vol.140 No.1

<P>Leukoaraiosis or white matter hyperintensities are frequently observed on magnetic resonance imaging of stroke patients. We investigated how white matter hyperintensity volumes affect stroke outcomes, generally and by subtype. In total, 5035 acute ischaemic stroke patients were enrolled. Strokes were classified as large artery atherosclerosis, small vessel occlusion, or cardioembolism. White matter hyperintensity volumes were stratified into quintiles. Mean age (+/- standard deviation) was 66.3 +/- 12.8, 59.6% male. Median (interquartile range) modified Rankin Scale score was 2 (1-3) at discharge and 1 (0-3) at 3 months; 16.5% experienced early neurological deterioration, and 3.3% recurrent stroke. The Cochran-Mantel-Haenszel test with adjustment for age, stroke severity, sex, and thrombolysis status showed that the distributions of 3-month modified Rankin Scale scores differed across white matter hyperintensity quintiles (P < 0.001). Multiple ordinal logistic regression analysis showed that higher white matter hyperintensity quintiles were independently associated with worse 3-month modified Rankin Scale scores; adjusted odds ratios (95% confidence interval) for the second to fifth quintiles versus the first quintile were 1.29 (1.10-1.52), 1.40 (1.18-1.66), 1.69 (1.42-2.02) and 2.03 (1.69-2.43), respectively. For large artery atherosclerosis (39.0%), outcomes varied by white matter hyperintensity volume (P = 0.01, Cochran-Mantel-Haenszel test), and the upper three white matter hyperintensity quintiles (versus the first quintile) had worse 3-month modified Rankin Scale scores; adjusted odds ratios were 1.45 (1.10-1.90), 1.86 (1.41-2.47), and 1.89 (1.41-2.54), respectively. Patients with large artery atherosclerosis were vulnerable to early neurological deterioration (19.4%), and the top two white matter hyperintensity quintiles were more vulnerable still: 23.5% and 22.3%. Moreover, higher white matter hyperintensities were associated with poor modified Rankin Scale improvement: adjusted odds ratios for the upper two quintiles versus the first quintile were 0.66 (0.47-0.94) and 0.62 (0.43-0.89), respectively. For small vessel occlusion (17.8%), outcomes tended to vary by white matter hyperintensitiy volume (P = 0.10, Cochran-Mantel-Haenszel test), and the highest quintile was associated with worse 3-month modified Rankin Scale scores: adjusted odds ratio for the fifth quintile versus first quintile, 1.98 (1.23-3.18). In this subtype, worse white matter hyperintensities were associated with worse National Institute of Health Stroke Scale scores at presentation. For cardioembolism (20.6%), outcomes did not vary significantly by white matter hyperintensity volume (P = 0.19, Cochran-Mantel-Haenszel test); however, the adjusted odds ratio for the highest versus lowest quintiles was 1.62 (1.09-2.40). Regardless of stroke subtype, white matter hyperintensities were not associated with stroke recurrence within 3 months of follow-up. In conclusion, white matter hyperintensity volume independently correlates with stroke outcomes in acute ischaemic stroke. There are some suggestions that stroke outcomes may be affected by leukoaraiosis differentially depending on stroke subtypes, to be confirmed in future investigations.</P>

The Relation between Chronic Kidney Disease and Cerebral Microbleeds: Difference between Patients with and without Diabetes

Ryu, Wi-Sun,Lee, Seung-Hoon,Kim, Chi Kyung,Kim, Beom Joon,Yoon, Byung-Woo SAGE Publications 2012 International journal of stroke Vol.7 No.7

<P>Cerebral microbleeds are an important radiologic marker of bleeding-prone brain and have been reported to be associated with the increased risk of intracerebral haemorrhage.</P>

<i>Dendropanax morbifera</i> Prevents Cardiomyocyte Hypertrophy by Inhibiting the Sp1/GATA4 Pathway

Sun, Simei,Li, Tianyi,Jin, Li,Piao, Zhe Hao,Liu, Bin,Ryu, Yuhee,Choi, Sin Young,Kim, Gwi Ran,Jeong, Ji Eun,Wi, An Jin,Lee, Song Ju,Kee, Hae Jin,Jeong, Myung Ho World Scientific Publishing Company 2018 The American journal of Chinese medicine Vol.46 No.5

<P>An extract of <I>Dendropanax morbifera</I> branch exerts antioxidant, anti-inflammatory, antithrombotic, and anticancer activities. The purpose of this study was to investigate the effect of the extract in isoproterenol-induced cardiac hypertrophy. Phalloidin staining showed that treatment with the extract dramatically prevents isoproterenol-induced H9c2 cell enlargement and the expression of cardiac hypertrophic marker genes, including atrial natriuretic peptide (ANP) and B-type brain natriuretic peptide (BNP). Further, pretreatment with the extract decreased isoproterenol-induced GATA4 and Sp1 expression in H9c2 cells. Overexpression of Sp1 induced the expression of GATA4. The forced expression of Sp1 or its downstream target GATA4, as well as the co-transfection of Sp1 and GATA4 increased the expression of ANP, which was decreased by treatment with the extract. To further elucidate the regulation of the Sp1/GATA4-mediated expression of ANP, knockdown experiments were performed. Transfection with small interfering RNAs (siRNAs) for Sp1 or GATA4 decreased ANP expression. The extract did not further inhibit the expression of ANP reduced by the transfection of GATA4 siRNA. Sp1 knockdown did not affect the expression of ANP that was induced by the overexpression of GATA4; however, GATA4 knockdown abolished the expression of ANP that had been induced by Sp1 overexpression. The extract treatment also attenuated the isoproterenol-induced activation of p38 MAPK, ERK1/2, and JNK1. Hesperidin, catechin, 2,5-dihydroxybenzoic acid, and salicylic acid are the main phenolic compounds present in the extract as observed by high performance liquid chromatography. Hesperidin and 2,5-dihydroxybenzoic acid attenuated isoproterenol-induced cardiac hypertrophy. These findings suggest that the <I>D. morbifera</I> branch extract prevents cardiac hypertrophy by downregulating the activation of Sp1/GATA4 and MAPK signaling pathways.</P>

Clinical Features of Adult COVID-19 Patients without Risk Factors before and after the Nationwide SARS-CoV-2 B.1.617.2 (Delta)-variant Outbreak in Korea: Experience from Gyeongsangnam-do

Ryu Byung-Han,Hong Sun In,Lim Su Jin,Cho Younghwa,Hwang Cheolgu,Kang Hyungseok,Kim Si-Ho,Wi Yu Mi,Hong Kyung-Wook,Bae In-Gyu,Cho Oh-Hyun 대한의학회 2021 Journal of Korean medical science Vol.36 No.49

Background: Data on severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) delta variant virulence are insufficient. We retrospectively compared the clinical features of adult coronavirus disease 2019 (COVID-19) patients without risk factors for severe COVID-19 who entered residential treatment centers (RTCs) before and after the delta variant outbreak. Methods: We collected medical information from two RTCs in South Korea. On the basis of nationwide delta variant surveillance, we divided the patients into two groups: 1) the delta-minor group (diagnosed from December 2020–June 2021, detection rate < 10%) and 2) the delta-dominant group (diagnosed during August 2021, detection rate > 90%). After propensity-score matching, the incidences of pneumonia, hospital transfer and need for supplemental oxygen were compared between the groups. In addition, risk factors for hospital transfer were analysed. Results: A total of 1,915 patients were included. The incidence of pneumonia (14.6% vs. 9.2%, P = 0.009), all-cause hospital transfer (10.4% vs. 6.3%, P = 0.020) and COVID-19- related hospital transfer (7.5% vs. 4.8%, P = 0.081) were higher in the delta-dominant group than those in the delta-minor group. In the multivariate analysis, the delta-dominant group was an independent risk factor for all-cause (adjusted odds ratio [aOR], 1.91; 95% confidence interval [CI], 1.16–3.13; P = 0.011) and COVID-19-related hospital transfer (aOR, 1.86; 95% CI, 1.04–3.32; P = 0.036). Conclusion: Hospitalization rates were increased in the adult COVID-19 patients during the delta variant nationwide outbreak. Our results showed that the delta variant may be more virulent than previous lineages.

의료기기의 광균일도 향상을 위한 LED 배열방식의 비교분석

손선국(Sun-Guk Son),황대위(Dae-Wi Hwang),송하연(Ha-Yeon Song),홍재화(Jae-Hwa Hong),김승일(seung-il kim),류장렬(Jang-Ryul Ryu) 한국정보기술학회 2011 Proceedings of KIIT Conference Vol.2011 No.5

본 논문은 LED 의료기기에서 LED(IR, RED)의 광균일도를 향상시키기 위한 효율적인 LED배열 구조에 관한 것으로, 특히, LED(150개 이상)가 요구되는 11″인치이상의 LED의료기기에 적용할 수 있는 다양한 LED 배열방식을 제안한다. 제안하는 배열 방식은 3종류의 등간격 평면형배열(Type1-1~2/Type2-1~2/Type3-1~2)과 3종류의 등간격 원통형배열(Type4-1~2/Type5-1~2/Type6-1~2)로, Type*-1~2는 LED와 Receiver와의 거리를 다르게 한 배열된 구조를 가지며, Type1-1~2/Type4-1~2는 Stripe형, Type2-1~2/Type5-1~2는 Mosaic형, Type3-1~2/Type6-1~2는 Delta형의 등간격의 구조를 갖는다. 제안된 3종류 배열구조에 대해 LightTools를 사용하여 광균일도를 실험하였다. 실험결과, 3종류의 Type 중 11″인치이상에서의 광균일도는 모든 Type에서 Receiver를 10㎜로 떨어뜨려 측정한 경우 좋았고, 특히 Mosaic형 방식에서 가장 양호한 결과를 나타내었으나 조도값은 Stripe형 방식에서 가장 높았다. This paper presents various LED array methods to improve the luminous intensity uniformity of LED(IR, RED) for LED medical equipment, and especially LED array methods applicable to the LED medical equipment over 11 inches requiring a great quantity of LEDs(over 150) are represented. The presented LED array methods consist of three types of equal-distance Planar array architectures (Type1-1~2/Type2-1~2/Type3-1~2) and three types of equal-distance Cylindrical array architectures (Type4-1~2/Type5-1~2/Type6-1~2). Basically, Type*-1~2 employs a structure that are arranged in different distance between LED and the Receiver. Type1-1~2/Type4-1~2 are Stripe type, Type2-1~2/Type5-1~2 are Mosaic type, Type3-1~2/Type6-1~2 have the structure of the Delta type of equal-distance array. LED array methods presented in this paper was all simulated using the LightTools. As a simulation result, all three types showed a good luminous intensity uniformity when measured at 10㎜ away and especially the Mosaic type showed a good luminous intensity uniformity whereas roughness values were the highest in the Stripe-type approach.