• Korean Journal of Radiology
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• 제24권12호
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• pp.1221-1231
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• 2023

Objective: To clinically validate the feasibility and accuracy of cine images acquired through the multitasking method, with no electrocardiogram gating and free-breathing, in measuring left ventricular (LV) function indices by comparing them with those acquired through the balanced steady-state free precession (bSSFP) method, with multiple breath-holds and electrocardiogram gating. Materials and Methods: Forty-three healthy volunteers (female:male, 30:13; mean age, 23.1 ± 2.3 years) and 36 patients requiring an assessment of LV function for various clinical indications (female:male, 22:14; 57.8 ± 11.3 years) were enrolled in this prospective study. Each participant underwent cardiac magnetic resonance imaging (MRI) using the multiple breath-hold bSSFP method and free-breathing multitasking method. LV function parameters were measured for both MRI methods. Image quality was assessed through subjective image quality scores (1 to 5) and calculation of the contrast-to-noise ratio (CNR) between the myocardium and blood pool. Differences between the two MRI methods were analyzed using the Bland-Altman plot, paired t-test, or Wilcoxon signed-rank test, as appropriate. Results: LV ejection fraction (LVEF) was not significantly different between the two MRI methods (P = 0.222 in healthy volunteers and P = 0.343 in patients). LV end-diastolic mass was slightly overestimated with multitasking in both healthy volunteers (multitasking vs. bSSFP, 60.5 ± 10.7 g vs. 58.0 ± 10.4 g, respectively; P < 0.001) and patients (69.4 ± 18.1 g vs. 66.8 ± 18.0 g, respectively; P = 0.003). Acceptable and comparable image quality was achieved for both MRI methods (multitasking vs. bSSFP, 4.5 ± 0.7 vs. 4.6 ± 0.6, respectively; P = 0.203). The CNR between the myocardium and blood pool showed no significant differences between the two MRI methods (18.89 ± 6.65 vs. 18.19 ± 5.83, respectively; P = 0.480). Conclusion: Multitasking-derived cine images obtained without electrocardiogram gating and breath-holding achieved similar image quality and accurate quantification of LVEF in healthy volunteers and patients.

• Korean Journal of Radiology
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• 제23권1호
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• pp.77-88
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• 2022

Objective: Our study aimed to evaluate the quality of radiomics studies on brain metastases based on the radiomics quality score (RQS), Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) checklist, and the Image Biomarker Standardization Initiative (IBSI) guidelines. Materials and Methods: PubMed MEDLINE, and EMBASE were searched for articles on radiomics for evaluating brain metastases, published until February 2021. Of the 572 articles, 29 relevant original research articles were included and evaluated according to the RQS, TRIPOD checklist, and IBSI guidelines. Results: External validation was performed in only three studies (10.3%). The median RQS was 3.0 (range, -6 to 12), with a low basic adherence rate of 50.0%. The adherence rate was low in comparison to the "gold standard" (10.3%), stating the potential clinical utility (10.3%), performing the cut-off analysis (3.4%), reporting calibration statistics (6.9%), and providing open science and data (3.4%). None of the studies involved test-retest or phantom studies, prospective studies, or cost-effectiveness analyses. The overall rate of adherence to the TRIPOD checklist was 60.3% and low for reporting title (3.4%), blind assessment of outcome (0%), description of the handling of missing data (0%), and presentation of the full prediction model (0%). The majority of studies lacked pre-processing steps, with bias-field correction, isovoxel resampling, skull stripping, and gray-level discretization performed in only six (20.7%), nine (31.0%), four (3.8%), and four (13.8%) studies, respectively. Conclusion: The overall scientific and reporting quality of radiomics studies on brain metastases published during the study period was insufficient. Radiomics studies should adhere to the RQS, TRIPOD, and IBSI guidelines to facilitate the translation of radiomics into the clinical field.

• Journal of Korean Neurosurgical Society
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• 제67권1호
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• pp.31-41
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• 2024

Objective : Collateral circulation is associated with the differential treatment effect of endovascular thrombectomy (EVT) in acute ischemic stroke. We aimed to verify the ability of the collateral map to predict futile EVT in patients with acute anterior circulation ischemic stroke. Methods : This secondary analysis of a prospective observational study included data from participants underwent EVT for acute ischemic stroke due to occlusion of the internal carotid artery and/or the middle cerebral artery within 8 hours of symptom onset. Multiple logistic regression analyses were conducted to identify independent predictors of futile recanalization (modified Rankin scale score at 90 days of 4-6 despite of successful reperfusion). Results : In a total of 214 participants, older age (odds ratio [OR], 2.40; 95% confidence interval [CI], 1.56 to 3.67; p<0.001), higher baseline National Institutes of Health Stroke Scale (NIHSS) scores (OR, 1.12; 95% CI, 1.04 to 1.21; p=0.004), very poor collateral perfusion grade (OR, 35.09; 95% CI, 3.50 to 351.33; p=0.002), longer door-to-puncture time (OR, 1.08; 95% CI, 1.02 to 1.14; p=0.009), and failed reperfusion (OR, 3.73; 95% CI, 1.30 to 10.76; p=0.015) were associated with unfavorable functional outcomes. In 184 participants who achieved successful reperfusion, older age (OR, 2.30; 95% CI, 1.44 to 3.67; p<0.001), higher baseline NIHSS scores (OR, 1.12; 95% CI, 1.03 to 1.22; p=0.006), very poor collateral perfusion grade (OR, 4.96; 95% CI, 1.42 to 17.37; p=0.012), and longer door-to-reperfusion time (OR, 1.09; 95% CI, 1.03 to 1.15; p=0.003) were associated with unfavorable functional outcomes. Conclusion : The assessment of collateral perfusion status using the collateral map can predict futile EVT, which may help select ineligible patients for EVT, thereby potentially reducing the rate of futile EVT.

• Journal of Ecology and Environment
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• 제47권4호
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• pp.200-210
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• 2023

Background: Cambaroides similis is an endangered candidate species living in the stream of South Korea. Freshwater crayfish is known to decline rapidly not only domestically, but also internationally. Its decline is projected to be further exacerbated due to climate change. Understanding physical characteristics of the habitat is crucial for the conservation of an organism. However, comprehensive data regarding the distribution and physical habitat characteristics of C. similis are currently unavailable in South Korea. Thus, the objective of this study was to ascertain preferred ranges for water depth, current velocity, and streambed substrate of C. similis using Weibull model. Results: In this study, C. similis was found at 59 sites across 12 regions in South Korea. Its optimal water depth preferences ranged from 11.9 cm to 30.1 cm. Its current velocity preferences ranged from 9.8 cm s^-1 to 29.1 cm s^-1. Its substrate preferences ranged from -5.1 𝜱_m to -2.5 𝜱_m. Median values of central tendency were determined as follows: water depth of 21.4 cm, current velocity of 21.2 cm s^-1, and substrate of -4.1 𝜱_m. Mean values of central tendency were determined as follows: water depth of 21.8 cm, current velocity of 22.0 cm s^-1, and substrate of -4.4 𝜱_m. Mode values of central tendency were determined as follows: water depth of 21.7 cm, current velocity of 20.1 cm s^-1, and substrate of -3.7 𝜱_m. Conclusions: Based on habitat suitability analysis, physical microhabitat characteristics of C. similis within a stream were identified as Run section with coarse particle substrate, low water depth, and slow current velocity. Due to high sensitivity of these habitats to environmental changes, prioritized selection and assessment of threats should be carried out as a primary step.

• Korean Journal of Radiology
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• 제21권8호
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• pp.998-1006
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• 2020

Objective: To compare the accuracies of quantitative computed tomography (CT) parameters and semiquantitative visual score in evaluating clinical classification of severity of coronavirus disease (COVID-19). Materials and Methods: We retrospectively enrolled 187 patients with COVID-19 treated at Tongji Hospital of Tongji Medical College from February 15, 2020, to February 29, 2020. Demographic data, imaging characteristics, and clinical data were collected, and based on the clinical classification of severity, patients were divided into groups 1 (mild) and 2 (severe/critical). A semiquantitative visual score was used to estimate the lesion extent. A three-dimensional slicer was used to precisely quantify the volume and CT value of the lung and lesions. Correlation coefficients of the quantitative CT parameters, semiquantitative visual score, and clinical classification were calculated using Spearman's correlation. A receiver operating characteristic curve was used to compare the accuracies of quantitative and semi-quantitative methods. Results: There were 59 patients in group 1 and 128 patients in group 2. The mean age and sex distribution of the two groups were not significantly different. The lesions were primarily located in the subpleural area. Compared to group 1, group 2 had larger values for all volume-dependent parameters (p < 0.001). The percentage of lesions had the strongest correlation with disease severity with a correlation coefficient of 0.495. In comparison, the correlation coefficient of semiquantitative score was 0.349. To classify the severity of COVID-19, area under the curve of the percentage of lesions was the highest (0.807; 95% confidence interval, 0.744-0.861: p < 0.001) and that of the quantitative CT parameters was significantly higher than that of the semiquantitative visual score (p = 0.001). Conclusion: The classification accuracy of quantitative CT parameters was significantly superior to that of semiquantitative visual score in terms of evaluating the severity of COVID-19.

• Korean Journal of Radiology
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• 제21권12호
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• pp.1294-1304
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• 2020

Objective: To determine whether T1 mapping could monitor the dynamic changes of injury in myocardial infarction (MI) and be histologically validated. Materials and Methods: In 22 pigs, MI was induced by ligating the left anterior descending artery and they underwent serial cardiovascular magnetic resonance examinations with modified Look-Locker inversion T1 mapping and extracellular volume (ECV) computation in acute (within 24 hours, n = 22), subacute (7 days, n = 13), and chronic (3 months, n = 7) phases of MI. Masson's trichrome staining was performed for histological ECV calculation. Myocardial native T1 and ECV were obtained by region of interest measurement in infarcted, peri-infarct, and remote myocardium. Results: Native T1 and ECV in peri-infarct myocardium differed from remote myocardium in acute (1181 ± 62 ms vs. 1113 ± 64 ms, p = 0.002; 24 ± 4% vs. 19 ± 4%, p = 0.031) and subacute phases (1264 ± 41 ms vs. 1171 ± 56 ms, p < 0.001; 27 ± 4% vs. 22 ± 2%, p = 0.009) but not in chronic phase (1157 ± 57 ms vs. 1120 ± 54 ms, p = 0.934; 23 ± 2% vs. 20 ± 1%, p = 0.109). From acute to chronic MI, infarcted native T1 peaked in subacute phase (1275 ± 63 ms vs. 1637 ± 123 ms vs. 1471 ± 98 ms, p < 0.001), while ECV progressively increased with time (35 ± 7% vs. 46 ± 6% vs. 52 ± 4%, p < 0.001). Native T1 correlated well with histological findings (R² = 0.65 to 0.89, all p < 0.001) so did ECV (R² = 0.73 to 0.94, all p < 0.001). Conclusion: T1 mapping allows the quantitative assessment of injury in MI and the noninvasive monitoring of tissue injury evolution, which correlates well with histological findings.

• 대한감각통합치료학회지
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• 제22권1호
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• pp.69-84
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• 2024

목적 : 본 연구에서는 발달성협응장애와 발달성협응장애 아동을 대상으로 한 과제-중심 접근법을 문헌 고찰을 통하여 알아보고자 하였다. 본론 : 본 연구는 발달성협응장애의 정의, 진단, 원인, 평가에 대한 전반적인 개요를 제시한다. 또한 신경운동과제훈련(Neuromotor Task Training; NTT)과 인지기반작업수행(Cognitive Orientation to daily Occupational Performance; CO-OP)의 중재 전략에 대해 알아보기 위해 2000년 1월부터 2023년 9월까지 게재된 국외 문헌 18편을 분석하였다. 선정된 문헌에서 언급된 중재의 목적은 작업치료 실행체계 4판(Occupational Therapy Practice Framework-4; OTPF-4)의 기준에 따라 분류하였다. 분류 결과, NTT는 클라이언트 요인(client factor) 영역에 대한 목표 설정의 빈도가 높았고, CO-OP는 작업(occupation) 영역에 대한 목표만을 설정하였다. 이러한 목표 설정의 차이는 두 중재 간 전략의 차이로 설명된다. 결론 : 발달성협응장애에 대한 전반적인 개요와 과제-중심 접근법의 중재에 대한 전략의 이해는 질환에 대한 인식도를 높이고 근거 기반 임상을 위한 기초 자료가 될 것이다.

• 방사선산업학회지
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• 제17권4호
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• pp.471-479
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• 2023

In In-situ radioactivity measurement techniques, efficiency calibration models use predefined models to simulate a sample's geometry and radioactivity distribution. However, simplified efficiency calibration models lead to uncertainties in the efficiency curves, which in turn affect the radioactivity concentration results. This study aims to develop an efficiency calibration optimization methodology to improve the accuracy of in-situ gamma radiation measurements for byproducts from industrial facilities. To accomplish the objective, a drive mechanism for rotational measurement of an byproduct simulator and a sample was constructed. Using ISOCS, an efficiency calibration model of the designed object was generated. Then, the sensitivity analysis of the efficiency calibration model was performed, and the efficiency curve of the efficiency calibration model was optimized using the sensitivity analysis results. Finally, the radiation concentration of the simulated subject was estimated, compared, and evaluated with the designed certification value. For the sensitivity assessment of the influencing factors of the efficiency calibration model, the ISOCS Uncertainty Estimator was used for the horizontal and vertical size and density of the measured object. The standard deviation of the measurement efficiency as a function of the longitudinal size and density of the efficiency calibration model decreased with increasing energy region. When using the optimized efficiency calibration model, the measurement efficiency using IUE was improved compared to the measurement efficiency using ISOCS at the energy of ²²⁸Ac (911 keV) for the nuclide under analysis. Using the ISOCS efficiency calibration method, the difference between the measured radiation concentration and the design value for each simulated subject measurement direction was 4.1% (1% to 10%) on average. The difference between the estimated radioactivity concentration and the design value was 3.6% (1~8%) on average when using the ISOCS IUE efficiency calibration method, which was closer to the design value than the efficiency calibration method using ISOCS. In other words, the estimated radioactivity concentration using the optimized efficiency curve was similar to the designed radioactivity concentration. The results of this study can be utilized as the main basis for the development of regulatory technologies for the treatment and disposal of waste generated during the operation, maintenance, and facility replacement of domestic byproduct generation facilities.

• 한국농림기상학회지
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• 제20권1호
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• pp.57-72
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• 2018

기후스마트농업(Climate-Smart Agriculture, CSA)이 성취되고 있는지에 대한 정량적인 평가방법을 구축하기 위해 타워 기반의 플럭스 관측 시계열 자료를 활용할 수 있다. 이 연구에서는 벼농사가 지배적인 전형적인 비균질 농경지를 대상으로 CSA의 첫 번째 목표와 관련된 생산성과 효율성 평가를 시도하였다. 이를 위해 해남 농경지에 위치한 KoFlux 사이트(HFK)에서 2003년부터 2015년까지 벼의 생장기간 동안에 관측된 탄소, 물 및 에너지 플럭스의 시계열 자료를 분석하여 일련의 정량적인 지표들을 평가하였다. 이 연구기간 동안에 HFK에서는 네 가지의 다른 품종(동진 1호; 2003-2008, 남평; 2009, 온누리; 2010-2011, 새누리; 2012-2015)의 벼가 경작되었다. 전반적으로 품종을 구분하지 않을 경우, 연구기간 동안의 HFK의 총일차생산(GPP)은 800 - 944 g C m-2, 물사용효율(WUE)은 1.91 - 2.80 g C kg H2O-1, 탄소사용효율(CUE)은 1.06 - 1.34, 그리고 광사용효율(LUE)은 0.99 - 1.55 g C MJ-1이었다. 벼 이외의 다른 식생이 포함된 HFK의 비균질성을 고려하여 어림 잡아 비교해 보면, 네 품종 중에서 동진1호를 재배했을 때에 HFK의 생산성이 아시아의 단일 벼논의 생산성과 비슷했고 WUE도 높았던 반면에 CUE는 상대적으로 낮았다. 또한, 새누리를 재배했을 때에도 HFK가 비슷하게 높은 생산성을 보였으나 동진1호보다 생장기간이 상대적으로 길었다. 따라서 동진1호가 지배적인 HFK가 CSA의 관점에서 더 좋은 특성을 보여 준다. 그러나 현실적으로는 농부들이 해충 저항성이 동진1호보다 높은 새 누리를 재배하고 있다. 이는 CSA의 나머지 두 목표의 하나인 탄력(resilience) 향상을 통한 적응력 강화와 관련된 것으로 온실가스 방출 저감을 포함한 총체적인 평가가 이루어져야 함을 시사하며, 이에 대한 평가와 분석이 현재 진행 중에 있다.

• 대한감각통합치료학회지
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• 제9권2호
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• pp.1-13
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• 2011

목적 : 본 연구는 한 아동을 대상으로 이루어진 작업치료중재서비스 안에서 이루어진 OTIPM의 적용 사례를 소개하고, 그 OTIPM에 기반한 임상적 추론과정과 재평가의 유익함과 시사점을 고찰하는 데 그 의의가 있다. 연구방법 : 대상 아동에 대한 작업치료중재서비스 안에서 OTIPM이 적용된 구체적 실행과정을 네 개의 주요부분으로 구분하여 기술하였다. 1) 클라이언트 중심의 수행문맥 확립; 2) 기초선 확립 및 원인해석(초기평가); 3) 중재 계획 및 실행; 4) 중재효과 확인(재평가). 수행 문맥은 보호자와의 면담을 통해 확립하였으며 초기평가 및 재평가에서 사용된 평가도구는 임상관찰 및 일본감각력평가(JSI-R), 덴버발달검사(DDST-2), 사회성숙도, 녹스학령전기놀이 척도(KPPS-R), 과제수행평가이다. 과제수행평가에서는 작업치료 실행 체계(Occupational Therapy Process Framework)에 의거한 수행기술 즉, 운동, 처리, 및 사회적 상호작용기술들을 평가하였으며, 표준화 된 수행기술검사인 운동처리기술검사(Assessment of Motor and Process Skill)와 사회기술평가(Evaluation of Social Participation)의 평가 체계를 사용하였다. 작업치료중재는 회복적모델의 감각통합치료활동과, 교육적모델의 보호자교육과, 습득적모델의 작업수행기술훈련이 계획되었으며, 일주일에 2회씩 총 4개월간 진행되었다. 결과 : 재평가 결과 사회연령과 사회성지수가 대상 아동의 연령에 맞게 향상되고, 전반적인 발달수준이 약 2년가량 향상되며, 전체적인 놀이수준 또한 13개월 향상되었다. 작업에 기반을 두어 설정되었던 중재 목표가 성취되었다. 아동의 보호자는 아동의 작업수행과 작업치료서비스에 대한 만족을 서술적으로 보고하였다. 결론 : 본 사례에서 작업치료사는 OTIPM에 기반하여 포괄적인 수행문맥을 확립하고 클라이언트 중심의 작업에 기반한 중재를 제공할 수 있었다. 임상적 추론을 통해 수행의 어려움의 원인을 보다 명확히 파악하여 수행의 하위요소뿐만 아니라 수행 전반의 향상을 이끌어내는 치료를 제공할 수 있었다. 뿐만 아니라 OTIPM에서 정의한 '클라이언트 무리'의 개념을 적용하여 클라이언트의 만족도를 이끌어내는 중재도 계획할 수 있었다. 본 연구를 통해, OTIPM이 클라이언트 중심의 작업수행의 성취도와 만족도 모두를 고려한 중재과정을 지향함으로써 '구체적인 작업참여의 포괄적인 향상'을 이끌어내는 데 유익한 작업치료중재과정모델임을 확인 할 수 있다.