Objective: The Daegu region experienced the first wave of the pandemic at the beginning of the coronavirus disease 2019 (COVID-19) outbreak in Korea. Other non-COVID-19-related treatments during a community outbreak, such as cardiovascular diseases, were expected to impact emergency departments. In acute myocardial infarctions, time is an important factor affecting the patient outcome. This study examined how community COVID-19 outbreak affected STsegment elevated myocardial infarction (STEMI) care in emergency departments. Methods: A retrospective analysis was performed on patients visiting five emergency departments in the Daegu area who were diagnosed with STEMI from February 18 to April 17 each year from 2018 to 2020. The demographic characteristics, prehospital variables, in-hospital time variables, and treatment results were collected. The cases were divided into the pre-COVID period and the COVID period for comparison. Results: The study included 254 patients (194 pre-COVID, 60 during COVID). The symptom-to-door time did not differ. Although the door-to-first doctor time was shortened (4 min vs. 2 min, P=0.01), the rate of coronary angiogram along with the door-to-angiogram time and the door-to-balloon time did not change. The length of stay in the emergency department was delayed during COVID-19 (median, 136 min vs. 404 min; P<0.01). The in-hospital length of stay and mortality were similar in both groups. Conclusion The time to treat STEMI was not delayed significantly during the first wave of the COVID-19 outbreak in the Daegu area compared with the pre-pandemic period. Mortality did not change. The length of stay was elongated significantly in the emergency department but not in the hospital.

Background and Objectives: The Fractional Flow Reserve and Intravascular UltrasoundGuided Intervention Strategy for Clinical Outcomes in Patients with Intermediate Stenosis (FLAVOUR) trial demonstrated non-inferiority of fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) compared with intravascular ultrasound (IVUS)-guided PCI. We sought to investigate the cost-effectiveness of FFR-guided PCI compared to IVUS-guided PCI in Korea. Methods: A 2-part cost-effectiveness model, composed of a short-term decision tree model and a long-term Markov model, was developed for patients who underwent PCI to treat intermediate stenosis (40% to 70% stenosis by visual estimation on coronary angiography).The lifetime healthcare costs and quality-adjusted life-years (QALYs) were estimated from the healthcare system perspective. Transition probabilities were mainly referred from the FLAVOUR trial, and healthcare costs were mainly obtained through analysis of Korean National Health Insurance claims data. Health utilities were mainly obtained from the Seattle Angina Questionnaire responses of FLAVOUR trial participants mapped to EQ-5D. Results: From the Korean healthcare system perspective, the base-case analysis showed that FFR-guided PCI was 2,451 U.S. dollar lower in lifetime healthcare costs and 0.178 higher in QALYs compared to IVUS-guided PCI. FFR-guided PCI remained more likely to be cost-effective over a wide range of willingness-to-pay thresholds in the probabilistic sensitivity analysis. Conclusions Based on the results from the FLAVOUR trial, FFR-guided PCI is projected to decrease lifetime healthcare costs and increase QALYs compared with IVUS-guided PCI in intermediate coronary lesion, and it is a dominant strategy in Korea.

Background: The Rapid-O2 oxygen insufflation device® (Rapid-O2) was designed primarily for rescue oxygenation in cannot intubate, cannot oxygenate (CICO) events; thus, hypercapnia is inevitable. Rapid-O2 was modified to enhance ventilation using the Venturi effect during expiration. Methods: To determine the most effective combination of inner catheters (20 gauge [G], 18 G, 16 G, 14 G, and 2-mm inner diameter [ID] transtracheal catheter [TTC]) and insufflation catheters (16 G, 14 G, and 2-mm ID TTC) for achieving optimum ventilation, insufflating and expiratory flows were measured at an oxygen flow rate of 15 L/min. The insufflating and expiratory pressures were measured at 6–15 L/min. The flows and pressures were measured using a gas flow analyzer. The insufflating and expiratory times were measured using a trachea-lung model to obtain minute volumes. To assess the improvement by modifying the Rapid-O2, minute volumes were measured using the Rapid-O2. Results: The most appropriate inner catheter was 18 G. The insufflating pressures ranged from 97 (2-mm ID TTC) to 377 cmH2O (16 G) at 15 L/min. During expiration, similar negative pressures of 50 cmH2O were measured in the insufflation catheters at 15 L/min. At lung compliance of 100 ml/cmH2O, the minute volumes through a 2-mm ID and 14 G insufflation catheters were 7.0 and 5.37 L/min, respectively, at 15 L/min. The minute volumes were significantly greater in modified Rapid-O2. Conclusions Modified Rapid-O2 provided sufficient minute volumes in adults using a 14 G or 2-mm ID insufflation catheter at 15 L/min, demonstrating its potential for ventilation in CICO events.

Background: We hypothesized that intranasal combination of dexmedetomidine (2 μg/kg) and ketamine (3 mg/kg) (IN DEXKET) improves the success rate of sedation in pediatric patients compared with chloral hydrate (CH; 50 mg/kg). Methods: This prospective, two-center, single-blinded, randomized controlled trial involved 136 pediatric patients (aged < 7 years) requiring procedural sedation. The participants were randomized to receive CH or IN DEXKET via a mucosal atomizer device. The primary outcome was the success rate of sedation (Pediatric Sedation State Scale, scores 1–3) within 15 min. The secondary outcomes included sedation failure at 30 min and overall complications of first-attempt sedation. Results: After excluding eight patients, 128 were included (CH = 66, IN DEXKET = 62). IN DEXKET showed a similar sedation success rate (75.8% [47/62] vs. 66.7% [44/66]; P = 0.330) but a lower complication rate (3.2% [2/62] vs. 16.7% [11/66]; P = 0.017) than CH. In the subgroup analysis for patients aged < 1 year, IN DEXKET showed a reduced complication rate than CH (2.6% [1/38] vs. 22.9% [8/35]; P = 0.012). In the subgroup analysis of children aged 1–7 years, IN DEXKET showed a higher sedation success rate within 15 min (79.2% [19/24] vs. 51.6% [16/31]; P = 0.049) and a lower sedation failure after 30 min (0% vs. 29.0% [9/31]; P = 0.003) than CH. Conclusions The intranasal combination of dexmedetomidine (2 μg/kg) and ketamine (3 mg/kg) is a safe and effective alternative to CH (50 mg/kg) for sedation in pediatric patients aged < 7 years.

Background: Atherosclerotic cardiovascular disease (ASCVD) is a major health concern, and lipoprotein(a) (Lp(a)) is an independent risk factor. However, there is limited evidence regarding Lp(a) and the risk of ASCVD in Asian populations. This study aimed to assess the predictive value of changes in coronary artery calcification (CAC) for ASCVD risk associated with Lp(a) level. Methods: Participants (n=2,750) were grouped according to their Lp(a) levels, and the association between Lp(a) and CAC progression was examined. CAC progression was defined as the occurrence of incident CAC or a difference ≥2.5 between the square root (√) of baseline and follow-up coronary artery calcium scores (CACSs) (Δ√transformed CACS). To adjust for differences in follow-up periods, Δ√transformed CACS was divided by the follow- up period (in years). Results: Over an average follow-up of 3.07 years, 18.98% of participants experienced CAC progression. Those with disease progression had notably higher Lp(a) levels. Higher Lp(a) tertiles correlated with increased baseline and follow-up CACS, CAC progression (%), and Δ√transformed CACS. Even after adjustment, higher Lp(a) levels were associated with CAC progression. However, annualized Δ√transformed CACS analysis yielded no significant results. Conclusion This study demonstrated an association between elevated Lp(a) levels and CAC progression in a general population without ASCVD. However, longer-term follow-up studies are needed to obtain meaningful results regarding CAC progression. Further research is necessary to utilize Lp(a) level as a predictor of cardiovascular disease and to establish clinically relevant thresholds specific to the Korean population.

Purpose: This study aimed to identify the factors influencing premedical students’ satisfaction with early clinical experience and determine the mediating effect of self-efficacy on the relationship between learning motivation and satisfaction. Methods: This cross-sectional study included 35 second-year premedical students who completed the early clinical experience course and responded to course evaluation questionnaires on self-efficacy, transfer motivation, and student satisfaction. The data were analyzed using descriptive statistics, Pearson’s correlation, Baron and Kenny’s hierarchical multiple regression analyses, and the Sobel test. Results: Student satisfaction was significantly correlated with self-efficacy (r=0.724, p<0.01) and transfer motivation (r=0.538, p<0.01). Self-efficacy and transfer motivation were also highly correlated (r=0.789, p<0.01). Multiple regression analyses and Sobel test indicated that self-efficacy fully mediated the relationship between student satisfaction and transfer motivation (Z=2.704, p<0.01). Conclusion In this study, early clinical experience program increased premedical students’ self-efficacy and transfer motivation for clinical knowledge and confirmed that self-efficacy mediated student satisfaction. These findings demonstrate the positive effects of early clinical experience on the medical school curriculum and suggest the need for educational strategies to increase self-efficacy in learning.

Objective: To evaluate the clinical efficacy of ultrafast dynamic contrast-enhanced (DCE)-MRI using a compressed sensing (CS) technique for differentiating benign and malignant soft-tissue tumors (STTs) and to evaluate the factors related to the grading of malignant STTs. Materials and Methods: A total of 165 patients (96 male; mean age, 61 years), comprising 111 with malignant STTs and 54 with benign STTs according to the 2020 WHO classification, underwent DCE-MRI with CS between June 2018 and June 2023. The clinical, qualitative, and quantitative parameters associated with conventional MRI were also obtained. During post-processing of the early arterial phase of DCE-MRI, the time-to-enhance (TTE), time-to-peak (TTP), initial area under the curve at 60 s (iAUC60), and maximum slope were calculated. Furthermore, the delayed arterial phase parameters of DCEMRI, including Ktrans , Kep, Ve, and iAUC values and time-concentration curve (TCC) types, were determined. Clinical and MRI parameters were statistically analyzed to differentiate between benign and malignant tumors and their correlation with tumor grading. Results: According to logistic regression analysis, the TTE value (P < 0.001) of the early arterial phase and Ve (P = 0.039) and iAUC (P = 0.006) values of the delayed arterial phase, as well as age, location, peritumoral edema, and contrast heterogeneity on conventional MRI, were significant (P = 0.001–0.015) in differentiating benign and malignant tumors. Among all the quantitative parameters, the TTE value had the highest accuracy, with an area under the receiver operating characteristic curve of 0.902. The grading of malignant tumors was significantly correlated with peritumoral edema; CE heterogeneity; visual diffusion restriction; minimum and mean ADC; TTP, Kep, and Ve values; and the TCC graph (all P < 0.05). Conclusion Among the quantitative parameters obtained using ultrafast DCE-MRI, early arterial phase TTE was the most accurate for distinguishing between benign and malignant tumors.

Objective: To compare the quality of deep learning-reconstructed turbo spin-echo (DL-TSE) and conventionally interpolated turbo spin-echo (Conv-TSE) techniques in contrast-enhanced MRI of the neck. Materials and Methods: Contrast-enhanced T1-weighted DL-TSE and Conv-TSE images were acquired using 3T scanners from 106 patients. DL-TSE employed a closed-source, ‘work-in-progress’ (WIP No. 1062, iTSE, version 10; Siemens Healthineers) algorithm for interpolation and denoising to achieve the same in-plane resolution (axial: 0.26 x 0.26 mm 2 ; coronal: 0.29 x 0.29 mm 2 ) while reducing scan times by 15.9% and 52.6% for axial and coronal scans, respectively. The full width at half maximum (FWHM) and percent signal ghosting were measured using stationary and flow phantom scans, respectively. In patient images, non-uniformity (NU), contrast-to-noise ratio (CNR), and regional mucosal FWHM were evaluated. Two neuroradiologists visually rated the patient images for overall quality, sharpness, regional mucosal conspicuity, artifacts, and lesions using a 5-point Likert scale. Results: FWHM in the stationary phantom scan was consistently sharper in DL-TSE. The percent signal ghosting outside the flow phantom was lower in DL-TSE (0.06% vs. 0.14%) but higher within the phantom (8.92% vs. 1.75%) compared to ConvTSE. In patient scans, DL-TSE showed non-inferior NU and higher CNR. Regional mucosal FWHM was significantly better in DL-TSE, particularly in the oropharynx (coronal: 1.08 ± 0.31 vs. 1.52 ± 0.46 mm) and hypopharynx (coronal: 1.26 ± 0.35 vs. 1.91 ± 0.56 mm) (both P < 0.001). DL-TSE demonstrated higher overall image quality (axial: 4.61 ± 0.49 vs. 3.32 ± 0.54) and sharpness (axial: 4.40 ± 0.56 vs. 3.11 ± 0.53) (both P < 0.001). In addition, mucosal conspicuity was improved, especially in the oropharynx (axial: 4.41 ± 0.67 vs. 3.40 ± 0.69) and hypopharynx (axial: 4.45 ± 0.58 vs. 3.58 ± 0.63) (both P < 0.001).Extracorporeal ghost artifacts were reduced in DL-TSE (axial: 4.32 ± 0.60 vs. 3.90 ± 0.71, P < 0.001) but artifacts overlapping anatomical structures were slightly more pronounced (axial: 3.78 ± 0.74 vs. 3.95 ± 0.72, P < 0.001). Lesions were detected with higher confidence in DL-TSE. Conclusion DL-based reconstruction applied to accelerated neck MRI improves overall image quality, sharpness, mucosal conspicuity in motion-prone regions, and lesion detection confidence. Despite more pronounced ghost artifacts overlapping anatomical structures, DL-TSE enables substantial scan time reduction while enhancing diagnostic performance.