• Korean Journal of Radiology
• /
• v.22 no.10
• /
• pp.1708-1718
• /
• 2021

Objective: The purpose of this study was to evaluate the magnetic resonance (MR) characteristics and applicability of new, uniform, extremely small iron-based nanoparticles (ESIONs) with 3-4-nm iron cores using contrast-enhanced magnetic resonance angiography (MRA). Materials and Methods: Seven types of ESIONs were used in phantom and animal experiments with 1.5T, 3T, and 4.7T scanners. The MR characteristics of the ESIONs were evaluated via phantom experiments. With the ESIONs selected by the phantom experiments, animal experiments were performed on eight rabbits. In the animal experiments, the in vivo kinetics and enhancement effect of the ESIONs were evaluated using half-diluted and non-diluted ESIONs. The between-group differences were assessed using a linear mixed model. A commercially available gadolinium-based contrast agent (GBCA) was used as a control. Results: All ESIONs showed a good T1 shortening effect and were applicable for MRA at 1.5T and 3T. The relaxivity ratio of the ESIONs increased with increasing magnetic field strength. In the animal experiments, the ESIONs showed peak signal intensity on the first-pass images and persistent vascular enhancement until 90 minutes. On the 1-week follow-up images, the ESIONs were nearly washed out from the vascular structures and organs. The peak signal intensity on the first-pass images showed no significant difference between the non-diluted ESIONs with 3-mm iron cores and GBCA (p = 1.000). On the 10-minutes post-contrast images, the non-diluted ESIONs showed a significantly higher signal intensity than did the GBCA (p < 0.001). Conclusion: In the phantom experiments, the ESIONs with 3-4-nm iron oxide cores showed a good T1 shortening effect at 1.5T and 3T. In the animal experiments, the ESIONs with 3-nm iron cores showed comparable enhancement on the first-pass images and superior enhancement effect on the delayed images compared to the commercially available GBCA at 3T.

• Korean Journal of Radiology
• /
• v.22 no.11
• /
• pp.1809-1821
• /
• 2021

Ovarian cystadenofibroma is a benign ovarian tumor that is characterized by a consistent percentage of masses, which remain indeterminate in ultrasonography and require magnetic resonance (MR) investigation; they may mimic borderline or malignant lesions. Three main morphologic patterns, resembling different ovarian neoplasms, can be identified in cystadenofibromas: multilocular solid lesions, unilocular cystic lesions with parietal thickening, and purely cystic masses. However, a cystoadenofibroma has typical features, such as T2-weighted hypointensity associated with no restrictions in diffusion-weighted imaging (the so-called "dark-dark appearance") and progressive post-contrast enhancement (type I perfusion curve). The purpose of this study was to review the features of ovarian cystadenofibromas in MR imaging and to suggest pearls and pitfalls regarding their correct diagnosis.

• Korean Journal of Radiology
• /
• v.22 no.8
• /
• pp.1279-1288
• /
• 2021

Objective: To assess the diagnostic performance of the Liver Imaging Reporting and Data System (LI-RADS) version 2018 treatment response algorithm (TRA) for the evaluation of hepatocellular carcinoma (HCC) treated with transarterial radioembolization. Materials and Methods: This retrospective study included patients who underwent transarterial radioembolization for HCC followed by hepatic surgery between January 2011 and December 2019. The resected lesions were determined to have either complete (100%) or incomplete (< 100%) necrosis based on histopathology. Three radiologists independently reviewed the CT or MR images of pre- and post-treatment lesions and assigned categories based on the LI-RADS version 2018 and the TRA, respectively. Diagnostic performances of LI-RADS treatment response (LR-TR) viable and nonviable categories were assessed for each reader, using histopathology from hepatic surgeries as a reference standard. Inter-reader agreements were evaluated using Fleiss κ. Results: A total of 27 patients (mean age ± standard deviation, 55.9 ± 9.1 years; 24 male) with 34 lesions (15 with complete necrosis and 19 with incomplete necrosis on histopathology) were included. To predict complete necrosis, the LR-TR nonviable category had a sensitivity of 73.3-80.0% and a specificity of 78.9-89.5%. For predicting incomplete necrosis, the LR-TR viable category had a sensitivity of 73.7-79.0% and a specificity of 93.3-100%. Five (14.7%) of 34 treated lesions were categorized as LR-TR equivocal by consensus, with two of the five lesions demonstrating incomplete necrosis. Interreader agreement for the LR-TR category was 0.81 (95% confidence interval: 0.66-0.96). Conclusion: The LI-RADS version 2018 TRA can be used to predict the histopathologic viability of HCCs treated with transarterial radioembolization.

• Korean Journal of Radiology
• /
• v.22 no.2
• /
• pp.243-252
• /
• 2021

Objective: To compare and correlate the findings of intravoxel incoherent motion (IVIM) magnetic resonance (MR) imaging and arterial spin labeling (ASL) imaging in characterizing parotid gland tumors. Materials and Methods: We retrospectively reviewed 56 patients with parotid gland tumors evaluated by MR imaging. The true diffusion coefficient (D), pseudo-diffusion coefficient (D^*), and fraction of perfusion (f) values of IVIM imaging and tumor-to-parotid gland signal intensity ratio (SIR) on ASL imaging were calculated. Spearman rank correlation coefficient, chi-squared, Mann-Whitney U, and Kruskal-Wallis tests with the post-hoc Dunn-Bonferroni method and receiver operating characteristic curve assessments were used for statistical analysis. Results: Malignant parotid gland tumors showed significantly lower D than benign tumors (p = 0.019). Within subgroup analyses, pleomorphic adenomas (PAs) showed significantly higher D than malignant tumors (MTs) and Warthin's tumors (WTs) (p < 0.001). The D^* of WTs was significantly higher than that of PAs (p = 0.031). The f and SIR on ASL imaging of WTs were significantly higher than those of MTs and PAs (p < 0.05). Significantly positive correlation was found between SIR on ASL imaging and f (r = 0.446, p = 0.001). In comparison with f, SIR on ASL imaging showed a higher area under curve (0.853 vs. 0.891) in discriminating MTs from WTs, although the difference was not significant (p = 0.720). Conclusion: IVIM and ASL imaging could help differentiate parotid gland tumors. SIR on ASL imaging showed a significantly positive correlation with f. ASL imaging might hold potential to improve the ability to discriminate MTs from WTs.

• Korean Journal of Radiology
• /
• v.21 no.5
• /
• pp.572-581
• /
• 2020

Objective: To evaluate the safety, feasibility, and efficacy of microwave ablation (MWA) for the treatment of primary hyperparathyroidism (PHPT). Materials and Methods: This study enrolled 67 PHPT patients (22 men, 45 women; mean age, 56.0 ± 16.3 years; range, 18-83 years) from January 2015 to December 2018. The laboratory data, including the serum intact parathyroid hormone (iPTH), calcium, phosphorus, and alkaline phosphatase (ALP) levels, were evaluated before MWA and again 2 hours, 1 day, 7 days, 1 month, 3 months, 6 months, 12 months, 18 months, and 24 months after. Results: Complete ablation was achieved with all 72 hyperplastic parathyroid glands found on the 67 patients enrolled, 64 of whom were treated in one session and 3 were treated over two sessions. The technical success rate was 100%. The median follow-up time was 13.6 months (range, 10.0-31.1 months). The clinical success rate was 89.4%. The volume reduction rate was 79.4% at 6 months. Compared to pre-MWA, the serum iPTH, calcium, phosphorus, and ALP levels had significantly improved 6 months post-MWA (iPTH, 157.3 pg/mL vs. 39.2 pg/mL; calcium, 2.75 ± 0.25 mmol/L vs. 2.34 ± 0.15 mmol/L; phosphorus, 0.86 ± 0.20 mmol/L vs. 1.12 ± 0.22 mmol/L; ALP, 79 U/L vs. 54 U/L, respectively; all, p < 0.01). Hoarseness was a major complication in 4 patients (6.0%), but it improved spontaneously within 2-3 months. Conclusion: MWA is safe, feasible, and effective for the treatment of PHPT.

• Korean Journal of Psychosomatic Medicine
• /
• v.28 no.1
• /
• pp.42-52
• /
• 2020

Objectives : Firefighters are always under stress due to their job environment, and they are likely to become psychologically vulnerable due to continuous exposure to traumatic events, which is a stressful situation that requires emergency standby at all times. The aims of this study were to examine mental health factors for each division of firefighters and to see the relationship between sleep and somatization symptoms among them. Methods : General characteristics and related inspections were conducted through self-reporting questionnaires for 1,264 firefighters working at Chungbuk fire stations. Several mental health factors were investigated by the Insomnia Severity Index, Severity of somatic symptoms, Impact of Event Scale, Perceived Stress Scale, Resilience Scale, Alcohol Dependent Screening Scale, and the Center for Epidemiologic Studies Depression Scale Depression Scale and Mini-International Neuropsychiatric Interview. Results : Among the mental health variables, the relationship between insomnia and somatization varies significantly depending on types of work. It was reported that the first aid team was significantly higher than the fire suppression and rescue team. Post-traumatic stress, depression and drinking also differ significantly depending on types of work. The first aid team reported more posttraumatic stress than the fire suppression team and more depressed mood than the rescue team. The administration part had more alcohol consumption than the fire suppression or first aid team. Resilience was significantly higher in the rescue team than the first aid team. No significant differences between the types of work about stress and suicide risks. Insomnia, stress, and post-traumatic stress were significant predictors of somatization among firefighters. Above all, insomnia was significant mental health variable affecting somatization. Conclusions : Various mental health factors were different according to the types of work in firefighters. The First aid team was more vulnerable to mental health variables such as insomnia and somatization than other divisions. Insomnia is the most important cause of somatization in firefighters, so it is recommended that they be treated for insomnia and to prepare institutional policies.

• Journal of the Korean Society of Earth Science Education
• /
• v.13 no.2
• /
• pp.162-174
• /
• 2020

This study aimed to develop a creative education class program using metaphor, one of the creative thinking techniques, and to examine the effectiveness of the program targeting for randomly sampled 338 students in six middle schools. The creative education class program with the metaphor was developed based on content elements concerning 'astronomy' in 2015 science curriculum revision in South Korea. The program was tested for validity after being modified and supplemented three times by forming a group of experts, and the final version of the program was applied to school education fields during four periods, including block time. To find out the effectiveness of the program and the implementation, creative education class satisfaction test and creative thinking process test were conducted. That is to say, the creative education class satisfaction test was conducted before treatment and the creative thinking process test was implemented both before and after treatment. The results of the study are as follows. First, in this study, the program was developed with the emphasis on students voluntarily and actively participating in creative education programs while utilizing creative thinking methods. Second, the statistical results of the pre- and post-class about the creative education program using the metaphor of creative thinking techniques represented significant results(p<.05). In other words, the two-dependent samples by students' pre-and post-score about the creative education class showed significant statistical test results (p<.05). It turned out that the creative education program using metaphor has had a positive impact on research participants. Third, in regards to the results of the creative education class satisfaction test, 101 out of 338 students(30%) answered 'Strongly Agree' and 137(41%) answered 'Agree', indicating the subjects' satisfaction with the class was high in general. On the other hand, concerning difficulties of the creative class, 137(41%) answered "Lack of time" as the main factor, followed by 98(30%) "Difficulties of problems they were required to solve", 73(22%) answered "Conflicts with friends", and 24(7%) said "Difficulties of contents." These responses were taken into account as considerations for further development of creative education programs.

• The Journal of Korean society of community based occupational therapy
• /
• v.10 no.1
• /
• pp.31-38
• /
• 2020

Objective : The purpose of this study is to investigate the effects of bilateral chewing exercise applied for 6 weeks on occlusion force and masseter muscle thickness in the elderly living in the community. Methods : This study recruited 25 community residents. All participants performed bilateral chewing exercise using equipment developed for the purpose of oral chewing exercise. The chewing exercise was divided into isometric and isotonic type and applied for about 20 minutes a day, five times a week for six weeks. For the evaluation, the masseter muscle thickness and the maximum occlusion force were measured three times at three week intervals using a portable ultrasound instrument and an occlusion force gauge. Results : As a result of the change in masseter muscle thickness, baseline, 3 weeks later, and 6 weeks later referred to 7.51±0.43, 7.63±0.44, and 7.83±0.46, respectively (F=3.819, p<.05). The post hoc test resulted in a significance between baseline and 6 weeks later (p=0.023). Similarly, as a result of the change in occlusion force, baseline, 3 weeks later, and 6 weeks later referred to 265±9.22, 268±9.57, and 271.59±10.16, respectively (F=3.031, p<.05). The post hoc test resulted in a significance between baseline and 6 weeks later (p=0.048). Conclusion : This study confirmed that bilateral chewing exercise was effective for increasing masseter muscle thickness and occlusion force in the elderly. Therefore, bilateral chewing exercise can be applied as a therapeutic exercise method for improving oral function.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.2
• /
• pp.130-141
• /
• 2020

The purpose of this study was to determine which fermented liquid fertilizer and application method yields the greatest amount of growth in red pepper (Capsicum annuum L.) and tomato (Lycopersicon esculentum MILL.) plants. Additionally, we investigated which extraction methods produce the most effective fertilizer with the highest levels of mineral nutrients. The liquid fertilizers used in this study were made from fish, bone and fish meal, red pepper leaves, and oil cake, and were extracted using fermentation or water and boiled water. In tomato plants, foliar-application of fermented fertilizer is known to promote more growth than application by drenching, regardless of the number of treatments (once or twice). In our studies, however, drenching with fertilizer promoted growth more effectively than foliar-application in red pepper plants. Studies in both tomato and red pepper have shown that the number of treatments does not significantly alter growth. Liquid fertilizers produced by a fermentation-extraction method promoted greater levels of growth in tomato compared to red pepper, and growth was greater when fertilizers were applied 20 (rather than 40) days post-sowing. Red pepper and tomato shoot fresh weight were affected more by fermented fertilizers than plant height 20 days post-sowing. In red pepper, we observed increased shoot fresh weight when using fermented liquid fertilizers with concentrations of 0.1% or greater. Tomato shoot fresh weight increased similarly in response to fermented fertilizer treatments at the same concentration levels, except those derived from fish. Fermented fish liquid fertilizer was only effective in increasing tomato shoot fresh weight in concentrations exceeding 1%. Red pepper and tomato shoot fresh weight also increased more than plant height in our studies using fermentation liquid fertilizers at 40 days after sowing. Red pepper fresh weight increased with application of bone + fish meal, red pepper leaf, and oil cake fertilizers at concentrations of 0.1%, but not with fish liquid fertilizer in concentrations under 0.5%. Shoot fresh weight in tomato increased with all liquid fertilizers. Growth in red pepper and tomato may be influenced by different kinds of fertilizers due to combinations of macro- and micro-nutrients, or specific macro-nutrients such as nitrogen, phosphoric acid, and potassium. The mineral nutrients found in fish, bone and fish meal, red pepper leaves, and oil cake were not easily extracted by fermentation; thus, liquid fertilizers made using water and boiled water methods more effectively promoted growth in red pepper and tomato due to the larger amounts of macronutrients eluted.

• Korean Journal of Environment and Ecology
• /
• v.34 no.2
• /
• pp.99-105
• /
• 2020

Migratory birds use a variety of breeding and wintering sites, and it is particularly important to understand more information on breeding and feeding sites for the conservation and management of endangered species. Black-faced spoonbills (Platalea minor) are an international endangered species distributed in East Asia. The majority of black-faced spoonbills breed on uninhabited islets off the west coast of the Korean Peninsula during the breeding season, and they are distributed in East Asia such as Taiwan, Hong Kong, southern China, Japan, and Jeju island during the winter season. In this study, we used a wild animal location tracking system to analyze and compare home ranges of three black-faced spoonbills spending the post-fledging stage in Gujido islet in Incheon and Chilsando islet in Yeonggwang each in 2015. The tree black-faced spoonbills in Guji islet showed a home range in coastal areas in Hwanghaenam-do and Gangneung-gun. The home range size (mean±SD) was estimated to be 425.49±116.95 ㎢ using 100% MCP, 43.61±18.51 ㎢ using KDE 95%, and 7.46±3.68 ㎢using KDE 50%. The tree black-faced spoonbills in Chilsando islet showed a home range in the Baeksu tidal flat and the Buan Saemangeum area with a size of 99.38±55.29 ㎢ using 100% MCP, 19.87±6.05 ㎢ using KDE 95%, and 1.16±0.53 ㎢ using KDE 50%. The figured indicated that the tree black-faced spoonbills breeding in Gujido islet had a wider home range than those breeding in Chilsando islet. During the post-fledging stage, the home ranges of black-faced spoonbills were mostly breeding in mudflats. Therefore, it is necessary to minimize human intervention, such as the construction of roads and structures and the human access, to protect the habitats during the period.