• Journal of Korea Water Resources Association
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• v.53 no.4
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• pp.249-258
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• 2020

Many climate studies have used the general circulation models (GCMs) for climate change, which can be currently available more than sixty GCMs as part of the Assessment Report (AR5). There are several types of uncertainty in climate studies using GCMs. Various studies are currently being conducted to reduce the uncertainty associated with GCMs, and the bias correction method used to reduce the difference between the simulated and the observed rainfall. Therefore, this study mainly considered climate change scenarios from nine GCMs, and then quantile mapping methods were applied to correct biases in climate change scenarios for each station during the historical period (1970-2005). Moreover, the monthly rainfall for the future period (2011-2100) is obtained from the RCP 4.5 scenario. Based on the bias-corrected rainfall, the standard deviation and the inter-quartile range (IQR) from the first to third quartiles were estimated. For 2071-2100, the uncertainty for the selection of GCMs is larger than that for the selection of bias correction methods and vice versa for 2011-2040. Therefore, this study showed that the selection of GCMs and the bias correction methods can affect the result for the future climate projection.

• Korean Journal of Radiology
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• v.24 no.11
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• pp.1151-1163
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• 2023

Objective: To develop a deep-learning-based bone age prediction model optimized for Korean children and adolescents and evaluate its feasibility by comparing it with a Greulich-Pyle-based deep-learning model. Materials and Methods: A convolutional neural network was trained to predict age according to the bone development shown on a hand radiograph (bone age) using 21036 hand radiographs of Korean children and adolescents without known bone development-affecting diseases/conditions obtained between 1998 and 2019 (median age [interquartile range {IQR}], 9 [7-12] years; male:female, 11794:9242) and their chronological ages as labels (Korean model). We constructed 2 separate external datasets consisting of Korean children and adolescents with healthy bone development (Institution 1: n = 343; median age [IQR], 10 [4-15] years; male: female, 183:160; Institution 2: n = 321; median age [IQR], 9 [5-14] years; male: female, 164:157) to test the model performance. The mean absolute error (MAE), root mean square error (RMSE), and proportions of bone age predictions within 6, 12, 18, and 24 months of the reference age (chronological age) were compared between the Korean model and a commercial model (VUNO Med-BoneAge version 1.1; VUNO) trained with Greulich-Pyle-based age as the label (GP-based model). Results: Compared with the GP-based model, the Korean model showed a lower RMSE (11.2 vs. 13.8 months; P = 0.004) and MAE (8.2 vs. 10.5 months; P = 0.002), a higher proportion of bone age predictions within 18 months of chronological age (88.3% vs. 82.2%; P = 0.031) for Institution 1, and a lower MAE (9.5 vs. 11.0 months; P = 0.022) and higher proportion of bone age predictions within 6 months (44.5% vs. 36.4%; P = 0.044) for Institution 2. Conclusion: The Korean model trained using the chronological ages of Korean children and adolescents without known bone development-affecting diseases/conditions as labels performed better in bone age assessment than the GP-based model in the Korean pediatric population. Further validation is required to confirm its accuracy.

• Korean Journal of Radiology
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• v.22 no.11
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• pp.1777-1785
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• 2021

Objective: To investigate the accuracy of the Agatston score obtained with the ultra-high-pitch (UHP) acquisition mode using tin-filter spectral shaping (Sn150 kVp) and a kVp-independent reconstruction algorithm to reduce the radiation dose. Materials and Methods: This prospective study included 114 patients (mean ± standard deviation, 60.3 ± 9.8 years; 74 male) who underwent a standard 120 kVp scan and an additional UHP Sn150 kVp scan for coronary artery calcification scoring (CACS). These two datasets were reconstructed using a standard reconstruction algorithm (120 kVp + Qr36d, protocol A; Sn150 kVp + Qr36d, protocol B). In addition, the Sn150 kVp dataset was reconstructed using a kVp-independent reconstruction algorithm (Sn150 kVp + Sa36d, protocol C). The Agatston scores for protocols A and B, as well as protocols A and C, were compared. The agreement between the scores was assessed using the intraclass correlation coefficient (ICC) and the Bland-Altman plot. The radiation doses for the 120 kVp and UHP Sn150 kVp acquisition modes were also compared. Results: No significant difference was observed in the Agatston score for protocols A (median, 63.05; interquartile range [IQR], 0-232.28) and C (median, 60.25; IQR, 0-195.20) (p = 0.060). The mean difference in the Agatston score for protocols A and C was relatively small (-7.82) and with the limits of agreement from -65.20 to 49.56 (ICC = 0.997). The Agatston score for protocol B (median, 34.85; IQR, 0-120.73) was significantly underestimated compared with that for protocol A (p < 0.001). The UHP Sn150 kVp mode facilitated an effective radiation dose reduction by approximately 30% (0.58 vs. 0.82 mSv, p < 0.001) from that associated with the standard 120 kVp mode. Conclusion: The Agatston scores for CACS with the UHP Sn150 kVp mode with a kVp-independent reconstruction algorithm and the standard 120 kVp demonstrated excellent agreement with a small mean difference and narrow agreement limits. The UHP Sn150 kVp mode allowed a significant reduction in the radiation dose.

• Journal of Korean Medical Science
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• v.33 no.48
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• pp.305.1-305.5
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• 2018

Background: In 1997 the Korean Association of Medical Journal Editors (KAMJE) instituted a program to evaluate member journals. Journals that passed the initial evaluation were indexed in the KoreaMed. Here, we report changes in measures of quality of the KAMJE member journals during the last 20 years. Methods: Quality measures used in the study comprised 3 assessment categories; self-assessment by journal editors, assessment of the journals by KAMJE reviewers, and by Korean health science librarians. Each used detailed criteria to score the journals on a scale of 0 to 5 or 6 in multiple dimensions. We compared scores at baseline evaluation and those after 7 years for 129 journals and compared improvements in journals indexed vs. not-indexed by the Web of Science (Science Citation Index Expanded; SCIE). Results: Among 251 KAMJE member journals at the end of 2015, 227 passed evaluation criteria and 129 (56%) had both baseline and 7-year follow-up assessment data. The journals showed improvement overall (increase in median [interquartile range; IQR] score from baseline, 0.47 [0.64]; 95% confidence interval [CI], 0.44-0.61; P < 0.001) and within each category (median [IQR] increase by editor's assessment, 0.17 [0.83]; 95% CI, 0.04-0.26; P = 0.007; by reviewer's, 0.45 [1.00]; 95% CI, 0.29-0.57; P < 0.001; by librarian's, 1.75 [1.08]; 95% CI, 1.77-2.18, P < 0.001). Before the foundation of KAMJE in 1996, there were only 5 Korean medical journals indexed in the MEDLINE and none in SCIE, but 24 journals in the MEDLINE and 34 journals in SCIE were indexed by 2016. Conclusion: The KAMJE journal evaluation program successfully contributes improving the quality of the member journals.

• Journal of Trauma and Injury
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• v.34 no.3
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• pp.155-161
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• 2021

Purpose: The coronavirus disease 2019 (COVID-19) pandemic has necessitated a redistribution of resources to meet hospitals' service needs. This study investigated the impact of COVID-19 on a regional trauma center in South Korea. Methods: We retrospectively reviewed cases of polytrauma at a single regional trauma center in South Korea between January 20 and September 30, 2020 (the COVID-19 period) and compared them to cases reported during the same time frame (January 20 to September 30) between 2016 and 2019 (the pre-COVID-19 period). The primary outcome was in-hospital mortality, and secondary outcomes included the number of daily admissions, hospital length of stay (LOS), and intensive care unit (ICU) LOS. Results: The mean number of daily admissions decreased by 15% during the COVID-19 period (4.0±2.0 vs. 4.7±2.2, p=0.010). There was no difference in mechanisms of injury between the two periods. For patients admitted during the COVID-19 period, the hospital LOS was significantly shorter (10 days [interquartile range (IQR) 4-19 days] vs. 16 days [IQR 8-28 days], p<0.001); however, no significant differences in ICU LOS and mortality were found. Conclusions: The observations at Regional Trauma Center, Pusan National University Hospital corroborate anecdotal reports that there has been a decline in the number of patients admitted to hospitals during the COVID-19 period. In addition, patients admitted during the COVID-19 pandemic had a significantly shorter hospital LOS than those admitted before the COVID-19 pandemic. These preliminary data warrant validation in larger, multi-center studies.

• Tuberculosis and Respiratory Diseases
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• v.84 no.3
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• pp.182-187
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• 2021

Background: Fractional exhaled nitric oxide (FeNO) is a non-invasive marker for eosinophilic airway inflammation and a good predictor of response to corticosteroids. There is a need for a reliable and accurate measurement method, as FeNO measurements have been widely used in clinical practice. Our study aimed to compare two FeNO analyzers and derive a conversion equation for FeNO measurements in adults. Methods: We included 99 participants who had chief complaints of chronic cough and difficulty in breathing. The participants underwent concurrent FeNO measurement using NIOX VERO (Circassia AB) and NObreath (Bedfont). We compared the values of the two devices and analyzed their correlation and agreement. We then formulated an equation to convert FeNO values measured by NObreath into those obtained by NIOX VERO. Results: The mean age of the participants was 51.2±17.1 years, with a female predominance (58.6%). Approximately 60% of the participants had asthma. The FeNO level measured by NIOX VERO (median, 27; interquartile range [IQR], 15-45) was significantly lower than that measured by NObreath (median, 38; IQR, 22-58; p<0.001). There was a strong positive correlation between the two devices (r=0.779, p<0.001). Additionally, Bland-Altman plots and intraclass correlation coefficient demonstrated a good agreement. Using linear regression, we derived the following conversion equation: natural log (Ln) (NObreath)=0.728×Ln (NIOX VERO)+1.244. Conclusion: The FeNO values of NIOX VERO and NObreath were in good agreement and had positive correlations. Our proposed conversion equation could help assess the accuracy of the two analyzers.

• Acute and Critical Care
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• v.33 no.4
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• pp.238-245
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• 2018

Background: Infection by multidrug-resistant (MDR) pathogens leads to poor patient outcomes in intensive care units (ICUs). Contact precautions are necessary to reduce the transmission of MDR pathogens. However, the importance of the surrounding environment is not well known. We studied the effects of ICU relocation on MDR respiratory pathogen detection rates and patient outcomes. Methods: Patients admitted to the ICU before and after the relocation were retrospectively analyzed. Baseline patient characteristics, types of respiratory pathogens detected, antibiotics used, and patient outcomes were measured. Results: A total of 463 adult patients admitted to the ICU, 4 months before and after the relocation, were included. Of them, 234 were admitted to the ICU before the relocation and 229 afterward. Baseline characteristics, including age, sex, and underlying comorbidities, did not differ between the two groups. After the relocation, the incidence rate of MDR respiratory pathogen detection decreased from 90.0 to 68.8 cases per 1,000 patient-days, but that difference was statistically insignificant. The use of colistin was significantly reduced from 53.5 days (95% confidence interval [CI], 20.3 to 86.7 days) to 18.7 days (95% CI, 5.6 to 31.7 days). Furthermore, the duration of hospital stay was significantly reduced from a median of 29 days (interquartile range [IQR], 14 to 50 days) to 21 days (IQR, 11 to 39 days). Conclusions: Incidence rates of MDR respiratory pathogen detection were not significantly different before and after ICU relocation. However, ICU relocation could be helpful in reducing the use of antibiotics against MDR pathogens and improving patient outcomes.

• Journal of Yeungnam Medical Science
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• v.40 no.2
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• pp.187-192
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• 2023

Background: This study aimed to present the short- and midterm outcomes after complete atrioventricular canal defect (CAVC) repair using a single-patch technique. Methods: This study included 30 children who underwent surgical correction of the CAVC using a single-patch technique. Results: The median age of the patients was 5.7 months (interquartile range [IQR], 5.0-7.5 months), and 23 patients (76.7%) had type A CAVC. Fourteen patients (46.7%) were female and 17 (56.7%) had been diagnosed with Down syndrome. The in-hospital mortality rate was 0%. No deaths were observed during a median follow-up of 4 years (IQR, 3.5-5.0 years). Patients without Down syndrome were associated with late moderate mitral regurgitation (MR) (p=0.02). Late MR less than moderate degree was observed in 96.6%, 78.5%, and 50% of patients after 2, 4, and 5 years of follow-up, respectively, while late tricuspid valve regurgitation less than moderate degree was observed in 96.7%, 85.9%, and 59.0% of patients after 2, 4, and 6 years of follow-up, respectively. After a median follow-up of 4 years, only one patient had required surgical repair of a left ventricular outflow tract obstruction, which occurred 26 months after the first operation. Multivariable logistic regression analysis adjusted for the type of CAVC, sex, Down syndrome, age, and weight revealed that the absence of Down syndrome was a risk factor for late moderate MR (MR-2) (odds ratio, 0.05; 95% confidence interval, 0.006-0.50; p=0.01). Conclusion: A single-patch technique for CAVC surgical repair is a safe method with acceptable short- and midterm results.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.1
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• pp.56-62
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• 2023

Backgrounds/Aims: Endoscopic retrograde cholangiopancreatography-guided gallbladder drainage (ERGD) is an alternative to percutaneous cholecystostomy (PTC) for hospitalized acute cholecystitis (AC) patients. Methods: We retrospectively analyzed propensity score matched (PSM) AC hospitalizations using the National Inpatient Sample database between 2016 and 2019 to compare the outcomes of ERGD and PTC. Results: After PSM, there were 3,360 AC hospitalizations, with 48.8% undergoing PTC and 51.2% undergoing ERGD. There was no difference in median length of stay between the PTC and ERGD cohorts (p = 0.110). There was a higher median hospitalization cost in the ERGD cohort, $62,562 (interquartile range [IQR] $40,707-97,978) compared to PTC, $40,413 (IQR $25,244-65,608; p < 0.001). The 30-day inpatient mortality was significantly lower in hospitalizations with ERGD compared to PTC (adjusted hazard ratio 0.16, 95% confidence interval [CI]: 0.1-0.41; p < 0.001). There was no difference in association with blood transfusions, acute renal failure, ileus, small bowel obstruction, and open cholecystectomy conversion (p > 0.05) between hospitalizations with ERGD and PTC. There was lower association of acute hypoxic respiratory failure (adjusted ratio [AOR] 0.46, 95% CI: 0.29-0.72; p = 0.001), hypovolemia (AOR 0.66, 95% CI: 0.49-0.82; p = 0.009) and higher association of lower gastrointestinal bleed (AOR 1.94, 95% CI: 1.48-2.54; p < 0.001) with ERGD compared to PTC. Conclusions: ERGD is a safer alternative to PTC in patients with AC. The risk complications are lower in ERGD compared to PTC but no difference exists based on mortality or conversion to open cholecystectomy.

• Korean Journal of Radiology
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• v.23 no.1
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• pp.60-67
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• 2022

Objective: To categorize multiparametric MRI features of Bacillus Calmette-Guérin (BCG)-related granulomatous prostatitis (GP) and discover potential manifestations for its differential diagnosis from prostate cancer. Materials and Methods: The cases of BCG-related GP in 24 male (mean age ± standard deviation, 66.0 ± 9.4 years; range, 50-88 years) pathologically confirmed between January 2011 and April 2019 were retrospectively reviewed. All patients underwent intravesical BCG therapy followed by a MRI scan. Additional follow-up MRI scans, including diffusion-weighted imaging (DWI), were performed in 19 patients. The BCG-related GP cases were categorized into three: A, B, or C. The lesions with diffusion restriction and homogeneous enhancement were classified as type A. The lesions with diffusion restriction and a poorly enhancing component were classified as type B. A low signal intensity on high b-value DWI (b = 1000 s/mm²) was considered characteristic of type C. Two radiologists independently interpreted the MRI scans before making a consensus about the types. Results: The median lesion size was 22 mm with the interquartile range (IQR) of 18-26 mm as measured using the initial MRI scans. The lesion types were A, B, and C in 7, 15, and 2 patients, respectively. Cohen's kappa value for the inter-reader agreement for the interpretation of the lesion types was 0.837. On the last follow-up MRI scans of 19 patients, the size decreased (median, 5.8 mm; IQR, 3.4-8.5 mm), and the type changed from A or B to C in 11 patients. The lesions resolved in four patients. In five patients who underwent prostatectomy, caseous necrosis on histopathology matched with the non-enhancing components of type B lesions and the entire type C lesions. Conclusion: BCG-related GP demonstrated three imaging patterns on multiparametric MRI. Contrast-enhanced T1-weighted imaging and DWI may play a role in its differential diagnosis from prostate cancer.