2.Clinical Efficacy of Ultrafast Dynamic Contrast-Enhanced MRI Using Compressed Sensing in Distinguishing Benign and Malignant Soft-Tissue Tumors
You Seon SONG ; In Sook LEE ; Young Jin CHOI ; Jeung Il KIM ; Kyung-Un CHOI ; Kangsoo KIM ; Kyungeun JANG
Korean Journal of Radiology 2025;26(1):43-53
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.
3.Effects of Deep Learning-Based Reconstruction on the Quality of Accelerated Contrast-Enhanced Neck MRI
Minkook SEO ; Kook-Jin AHN ; Hyun-Soo LEE ; Marcel Dominik NICKEL ; Jinhee JANG ; Yeon Jong HUH ; Ilah SHIN ; Ji Young LEE ; Bum-soo KIM
Korean Journal of Radiology 2025;26(5):446-459
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.
4.Far-Lateral Transforaminal Unilateral Biportal Endoscopic Lumbar Discectomy for Upper Lumbar Disc Herniations
Jin Seop HWANG ; Sang Hyub LEE ; Dain JEONG ; Jae-Won JANG ; Yong Eun CHO ; Dong-Geun LEE ; Choon Keun PARK ; Chung Kee CHOUGH
Neurospine 2025;22(1):14-27
Objective:
The upper lumbar region has distinctive anatomical characteristics that contribute to the challenges of performing discectomy. We introduce far-lateral transforaminal unilateral biportal endoscopic (UBE) lumbar discectomy for central or paracentral disc herniations in the upper lumbar region.
Methods:
We conducted retrospective review of the patients who underwent a far-lateral transforaminal UBE lumbar discectomy at our institution from January 2018 to September 2024. The electronic medical records, operative records, and radiologic images of the patients were reviewed.
Results:
A total of 27 patients underwent far-lateral transforaminal UBE lumbar discectomy for central or paracentral disc herniations in the upper lumbar region. The patient had a mean age of 54.0 ± 13.7 years. Operation was performed at the L1–2 level in 3 patients (11.1%), L2–3 in 9 patients (33.3%), and L3–4 in 15 patients (55.6%). The patients were followed-up for a mean of 27.7 ± 19.3 months. The Oswestry Disability Index was significantly decreased from 36.3 ± 6.8 preoperatively to 3.7 ± 3.3 at last follow-up (p < 0.001). The visual analogue scale (VAS) back was significantly decreased from 7.8 ± 0.9 preoperatively to 3.1 ± 0.6 postoperative day 2 (p < 0.001). The VAS leg was significantly decreased from 8.1 ± 0.8 preoperatively to 2.3 ± 0.7 postoperative day 2 (p < 0.001).
Conclusion
The far-lateral transforaminal UBE lumbar discectomy would be a viable surgical option for upper lumbar disc herniations.
5.18F-FDOPA PET/CT in Oncology: Procedural Guideline by the KoreanSociety of Nuclear Medicine
Yong-Jin PARK ; Joon Ho CHOI ; Hyunjong LEE ; Seung Hwan MOON ; Inki LEE ; Joohee LEE ; Jang YOO ; Joon Young CHOI ;
Nuclear Medicine and Molecular Imaging 2025;59(1):41-49
This guideline outlines the use of 3,4-dihydroxy-6- 18F-fluoro-L-phenylalanine positron emission tomography / computed tomography for the diagnosis and management of neuroendocrine tumors, brain tumors, and other tumorous conditions. It provides detailed recommendations on patient preparation, imaging procedures, and result interpretation. Based on inter-national standards and adapted to local clinical practices, the guideline emphasizes safety, quality control, and the effec-tive application of 3,4-dihydroxy-6- 18F-fluoro-L-phenylalanine positron emission tomography / computed tomography for various tumors such as insulinomas, pheochromocytomas, and medullary thyroid carcinoma. It also addresses the use of premedication with carbidopa, fasting protocols, and optimal imaging techniques. The aim is to assist nuclear medicine professionals in delivering precise diagnoses, improving patient outcomes, and accommodating evolving medical knowl-edge and technology. This comprehensive document serves as a practical resource to enhance the accuracy, quality, and safety of 3,4-dihydroxy-6- 18F-fluoro-L-phenylalanine positron emission tomography / computed tomography in oncology.
6.Medical accident compensation systems in obstetrics: a comparison among Korea, Japan, and Taiwan, with suggestions for Korea
Kyong-No LEE ; Sang Hyun KIM ; Se Jin LEE ; Wook JANG ; Sunghun NA ; So Yun KIM
Journal of the Korean Medical Association 2025;68(3):148-156
Korea’s medical accident compensation system is a vital national initiative designed to create a stable environment for both mothers and healthcare professionals. This article examines how Korea's neighboring countries, Taiwan and Japan, operate their obstetric compensation systems to draw lessons and implications for Korea's approach.Current Concepts: Korea's medical malpractice compensation system is fully funded by the government, and the amount is determined by the Compensation Review Committee, which considers the type of accident and, in cases of cerebral palsy, the degree of impairment, with awards reaching up to 30 million won. Japan experienced severe declines in birth rates, a shortage of obstetricians, and the closure of maternity hospitals due to increasing medical litigation. In response, the government ,in 2009, introduced a no-fault obstetric compensation system that covers cerebral palsy cases regardless of negligence. Taiwan faced a surge in medical disputes, particularly in obstetrics and gynecology, with maternal lawsuits comprising 14% of all cases. In 2016, the government introduced the Childbirth Accident Emergency Relief Act, achieving a 93.9% compensation approval rate Discussion and Conclusion: Observing these challenges, young doctors are increasingly dissuaded from pursuing careers in obstetrics and gynecology doctor, thereby accelerating the decline of maternity care services. To maintain a stable medical environment, compensation amounts should be adjusted to reflect actual medical costs, and reimbursement rates for obstetric procedures should be re-evaluated. Drawing on the successful implementations in Japan and Taiwan, South Korea must establish a sustainable and protective obstetric care system at the national level.
7.Effect of regional COVID-19 outbreak to emergency department response on acute myocardial infarction: a multicenter retrospective study
Young Wook KIM ; Sungbae MOON ; Hyun Wook RYOO ; Jae Yun AHN ; Jung Bae PARK ; Dong Eun LEE ; Sang Hun LEE ; Sangchan JIN ; You Ho MUN ; Jung Ho KIM ; Tae Chang JANG
Journal of the Korean Society of Emergency Medicine 2025;36(2):72-82
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.
8.Cost-effectiveness of Fractional Flow Reserve Versus Intravascular Ultrasound to Guide Percutaneous Coronary Intervention: Results From the FLAVOUR Study
Doyeon HWANG ; Hea-Lim KIM ; Jane KO ; HyunJin CHOI ; Hanna JEONG ; Sun-ae JANG ; Xinyang HU ; Jeehoon KANG ; Jinlong ZHANG ; Jun JIANG ; Joo-Yong HAHN ; Chang-Wook NAM ; Joon-Hyung DOH ; Bong-Ki LEE ; Weon KIM ; Jinyu HUANG ; Fan JIANG ; Hao ZHOU ; Peng CHEN ; Lijiang TANG ; Wenbing JIANG ; Xiaomin CHEN ; Wenming HE ; Sung Gyun AHN ; Ung KIM ; You-Jeong KI ; Eun-Seok SHIN ; Hyo-Soo KIM ; Seung-Jea TAHK ; JianAn WANG ; Tae-Jin LEE ; Bon-Kwon KOO ;
Korean Circulation Journal 2025;55(1):34-46
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.
9.Transcatheter ventilation with a modified Rapid-O2 oxygen insufflation device
Jaewon JANG ; Hye Jin KIM ; Hyun Joo KIM ; Wyun Kon PARK
Korean Journal of Anesthesiology 2025;78(1):61-72
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.
10.Comparison of combined intranasal dexmedetomidine and ketamine versus chloral hydrate for pediatric procedural sedation: a randomized controlled trial
Young-Eun JANG ; Eun-Young JOO ; Jung-Bin PARK ; Sang-Hwan JI ; Eun-Hee KIM ; Ji-Hyun LEE ; Hee-Soo KIM ; Jin-Tae KIM
Korean Journal of Anesthesiology 2025;78(3):248-260
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.

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