• Journal of the Korean Orthopaedic Association
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• v.54 no.4
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• pp.327-335
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• 2019

Purpose: To investigate the radiological efficacy of polymethylmethacrylate (PMMA) augmentation of pedicle screw operation in osteoporotic vertebral compression fractures (OVCF) patients. Materials and Methods: Twenty OVCF patients, who underwent only posterior fusion using pedicle screws with PMMA augmentation, were included in the study. The mean follow-up period was 15.6 months. The demographic data, bone mineral density (BMD), fusion segments, number of pedicle screws, and amount of PMMA were reviewed as medical records. To analyze the radiological outcomes, the radiologic parameters were measured as the time serial follow-up (preoperation, immediately postoperation, postoperation 6 weeks, 3, 6 months, and 1 year follow-up). Results: A total of 20 patients were examined (16 females [80.0%]; mean age, 69.1±8.9 years). The average BMD was -2.5±0.9 g/cm². The average cement volume per vertebral body was 6.3 ml. The mean preoperative Cobb angle of focal kyphosis was 32.7°±7.0° and was improved significantly to 8.7°±6.9° postoperatively (p<0.001), with maintenance of the correction at the serial follow-up, postoperatively. The Cobb angle of instrumented kyphosis, wedge angle, and sagittal index showed similar patterns. In addition, the anterior part of fractured vertebral body height averaged 11.0±5.0 mm and was improved to 18.5±5.7 mm postoperatively (p=0.006), with maintenance of the improvement at the 3-month, 6-month, and 1-year follow-up. Conclusion: The reinforcement of pedicle screws using PMMA augmentation may be a feasible surgical technique for OVCF. Moreover, it appears to be appropriate for improving the focal thoracolumbar/lumbar kyphosis and is maintained well after surgery.

• Journal of the Korean Orthopaedic Association
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• v.54 no.2
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• pp.127-132
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• 2019

Purpose: The aim of this study was to determine if preoperative temporary discontinuation of antiplatelet medication (aspirin, clopidogrel, or cilostazol) is a safe procedure that does not increase early postoperative bleeding and allogenic blood transfusion after a total knee arthroplasty. Materials and Methods: A retrospective analysis was conducted among consecutive patients who underwent navigation assisted primary total knee arthroplasty performed by a single surgeon, from January 2013 to December 2016. A total of 369 patients enrolled in this study were divided into two groups, 271 patients with no history of antiplatelet therapy and 98 patients who underwent 7 days of temporary withdrawal of antiplatelet therapy. Comparative analysis between the two groups, on the variation of hemoglobin and hematocrit during the first and second postoperative days, was conducted to determine the amount of early postoperative bleeding and the frequency of allogenic blood transfusion during hospitalization. Results: The variation of hemoglobin, hematocrit during the first and second postoperative days and the frequency of allogenic blood transfusion between no history of antiplatelet medication and discontinuation antiplatelet medication before 7 days from surgery were similar in both groups. Of the 369 patients, 149 patients received a blood transfusion during their hospitalization. Compared to patients who did not receive a blood transfusion, those who did received blood transfusion were significantly older in age, smaller in height, lighter in weight, and showed significantly lower preoperative hemoglobin and hematocrit values. No statistically significant differences in sex, preoperative American Society of Anesthesiologists scores, and the history of antiplatelet medication until 7 days prior to surgery were observed between the two groups according to blood transfusion. Conclusion: Compared to patients with no history of antiplatelet medication, the temporary discontinuation of antiplatelet medication 7 days prior to surgery in patients undergoing antiplatelet medication did not increase the amount of postoperative bleeding or the need for allogenic blood transfusion.

• Journal of the Korean Orthopaedic Association
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• v.54 no.3
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• pp.269-275
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• 2019

Purpose: This study analyzed the treatment effects of drain insertion in the posteromedial portal after an arthroscopic synovectomy and posterior septum resection for pyogenic arthritis. Materials and Methods: From June 2005 to December 2016, 56 cases (55 patients, 1 case of bilateral knee) were diagnosed with pyogenic arthritis and arthroscopic treatment was performed. Fourteen patients (25.0%) were identified with causative organisms. The average follow-up period was 12.3 months, and the mean age was 67.8 years old. Twenty-four cases were males and 31 cases were females. Kellgrene-Lawrence grade (K-L grade) I was 6 patients, II was 20 patients, III was 11 patients, and IV was 18 patients. Surgery was performed through six portal. The posterior septum was removed and a drainage tube was inserted from the posterior medial side to the posterior side of the joint. The Lysholm score was used after surgery for a functional evaluation. The K-L grade at the time of admission and at the last follow-up were compared for a radiological evaluation. Results: The mean normalization period of the C-reactive protein was 59.8 days (6-164 days). Intravenous antibiotics were used for an average of 37.1 days. The results of the functional evaluation revealed a mean Lysholm score of 64.5 (30-98) in a total of 56 cases. Two reoperations was performed, but the treatment was completed with same method in all patients. The K-L grade was similar at the time of surgery and at the last follow-up (p>0.05). Conclusion: The method of drain insertion in the posteromedial portal after arthroscopic synovectomy and posterior septum resection for pyogenic arthritis is an effective technique that can obtain satisfactory results by inducing proper exudate discharge.

• Journal of The Korean Association For Science Education
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• v.44 no.3
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• pp.249-262
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• 2024

The purpose of this study is to analyze the achievement standards of the 2015 revision and 2022 revision of the science curriculum using the TIMSS 2023 science cognitive domain analysis framework. The subject of the study is the achievement standards for all elementary school areas in the 2015 and 2022 revised science curriculum. Three field teachers and one elementary science education expert who majored in elementary science education participated in the research analysis. The results of this study are as follows. First, in the 2022 revised movement and energy field, the ratio of the 'knowing' area was about 16% higher than the 2015 revision, and the ratio of the 'reasoning' area also increased by about 5.8%. Second, in the material field, the proportion of TIMSS 2023 cognitive domains was in the order of 'knowing', 'applying', and 'reasoning' regardless of grade group and curriculum revision period. Third, in the field of life sciences, the proportion of TIMSS 2023 cognitive domains differed depending on grade group and curriculum revision period. Fourth, in the Earth and Space field of the 2022 revision, similar to the other three fields, the proportion of the 'Knowing' field increased and while the 'Applying' field decreased. However, in the 2022 revision, the 'reasoning' area in all three other fields increased, but decreased only in the earth and space fields. Fifth, the 2015 revised integrated unit and the 2022 revised science and society field only covered the elements of 'recognizing' and 'presenting examples' in the 'knowing' area, 'making relationships' and 'explaining' in the 'applying' area and 'Synthesize' in the 'reasoning' area. In the 2022 revised elementary school science field, the proportion of the 'knowing' section was 52.5%, the proportion of the 'applying' section was 33.8%, and the proportion of the 'reasoning' section was 13.7%. In conclusion, in the 2022 revised elementary science achievement standards, the ratio of the 'applying' and 'reasoning' areas was low because the reliance on the 'knowing' area was too high.

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.669-679
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• 2022

Purpose To evaluate the feasibility of pediatric low-dose facial CT reconstructed with filtered back projection (FBP) using adequate kernels. Materials and Methods We retrospectively reviewed the clinical and imaging data of children aged < 10 years who underwent facial CT at our emergency department. The patients were divided into two groups: low-dose CT (LDCT; Group A, n = 73) with a fixed 80-kVp tube potential and automatic tube current modulation (ATCM) and standard-dose CT (SDCT; Group B, n = 40) with a fixed 120-kVp tube potential and ATCM. All images were reconstructed with FBP using bone and soft tissue kernels in Group A and only bone kernel in Group B. The groups were compared in terms of image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). Two radiologists subjectively scored the overall image quality of bony and soft tissue structures. The CT dose index volume and dose-length product were recorded. Results Image noise was higher in Group A than in Group B in bone kernel images (p < 0.001). Group A using a soft tissue kernel showed the highest SNR and CNR for all soft tissue structures (all p < 0.001). In the qualitative analysis of bony structures, Group A scores were found to be similar to or higher than Group B scores on comparing bone kernel images. In the qualitative analysis of soft tissue structures, there was no significant difference between Group A using a soft tissue kernel and Group B using a bone kernel with a soft tissue window setting (p > 0.05). Group A showed a 76.9% reduction in radiation dose compared to Group B (3.2 ± 0.2 mGy vs. 13.9 ± 1.5 mGy; p < 0.001). Conclusion The addition of a soft tissue kernel image to conventional CT reconstructed with FBP enables the use of pediatric low-dose facial CT protocol while maintaining image quality.

• Journal of the Korean Society of Radiology
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• v.82 no.6
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• pp.1477-1492
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• 2021

Purpose Dedicated breast CT is an emerging volumetric X-ray imaging modality for diagnosis that does not require any painful breast compression. To improve the detection rate of weakly enhanced lesions, an adaptive image rescaling (AIR) technique was proposed. Materials and Methods Two disks containing five identical holes and five holes of different diameters were scanned using 60/100 kVp to obtain single-energy CT (SECT), dual-energy CT (DECT), and AIR images. A piece of pork was also scanned as a subclinical trial. The image quality was evaluated using image contrast and contrast-to-noise ratio (CNR). The difference of imaging performances was confirmed using student's t test. Results Total mean image contrast of AIR (0.70) reached 74.5% of that of DECT (0.94) and was higher than that of SECT (0.22) by 318.2%. Total mean CNR of AIR (5.08) was 35.5% of that of SECT (14.30) and was higher than that of DECT (2.28) by 222.8%. A similar trend was observed in the subclinical study. Conclusion The results demonstrated superior image contrast of AIR over SECT, and its higher overall image quality compared to DECT with half the exposure. Therefore, AIR seems to have the potential to improve the detectability of lesions with dedicated breast CT.

• Journal of the Korean Society of Radiology
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• v.82 no.6
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• pp.1493-1504
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• 2021

Purpose This study aimed to evaluate the utility of the 16-cm axial volume scan technique for calculating the coronary artery calcium score (CACS) using non-enhanced chest CT. Materials and Methods This study prospectively enrolled 20 participants who underwent both, non-enhanced chest CT (16-cm-coverage axial volume scan technique) and calcium-score CT, with the same parameters, differing only in slice thickness (in non-enhanced chest CT = 0.625, 1.25, 2.5 mm; in calcium score CT = 2.5 mm). The CACS was calculated using the conventional Agatston method. The difference between the CACS obtained from the two CT scans was compared, and the degree of agreement for the clinical significance of the CACS was confirmed through sectional analysis. Each calcified lesion was classified by location and size, and a one-to-one comparison of non-contrast-enhanced chest CT and calcium score CT was performed. Results The correlation coefficients of the CACS obtained from the two CT scans for slice thickness of 2.5, 1.25, and 0.625 mm were 0.9850, 0.9688, and 0.9834, respectively. The mean differences between the CACS were -21.4% at 0.625 mm, -39.4% at 1.25 mm, and -76.2% at 2.5 mm slice thicknesses. Sectional analysis revealed that 16 (80%), 16 (80%), and 13 (65%) patients showed agreement for the degree of coronary artery disease at each slice interval, respectively. Inter-reader agreement was high for each slice interval. The 0.625 mm CT showed the highest sensitivity for detecting calcified lesions. Conclusion The values in the non-contrast-enhanced chest CT, using the 16-cm axial volume scan technique, were similar to those obtained using the CACS in the calcium score CT, at 0.625 mm slice thickness without electrocardiogram gating. This can ultimately help predict cardiovascular risk without additional radiation exposure.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.276-284
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• 2023

Nitrogen is a major and essential macronutrient for plant growth and development. However, excessive nitrogen application can lead to ecological pollution or greenhouse gas emissions, consequently resulting in climate change. In this study, we used 153 genetic resources of rice to evaluate the effects of the levels of nitrogen application on grain yield and yield-related traits. Significant differences were noted in the yield and yield-related traits of genetic resources between two nitrogen application levels, namely, 4.5 kg/10a (NN: normal nitrogen condition) and 9.0 kg/10a (LN: low-nitrogen condition). Among the tested traits, days to heading (DTH), clum length (CL), grain yield per plant (GYP), number of panicles per plant (NPP), and number of spikelets per panicle (NSP) decreased by 1.8 to 17.9% when the nitrogen application levels decreased from NN to LN. The 1,000-grain weight (TWG) and percentage of ripened grain (PRG) increased by 2.6 to 11.2% under these conditions. Based on nitrogen application levels, two-way analysis of variance (ANOVA) demonstrated significant differences in GYP, NPP, and PRG but not in NSP and TGW. NPP exhibited negative correlations with NSP (-0.44) and TGW (-0.44), and TGW displayed a negative correlation with PRG (-0.34), whereas, GYP exhibited a positive correlation with PRG (0.37) and NSP (0.38). A similar pattern was recorded under the LN condition. NPP, TGW, and PRG were clustered as PA (principle axis) 1 under the LN condition by factor analysis. NSP and GYP were clustered as PA (principle axis) 2. These results demonstrated NPP and NSP as the primary factors contributing to the decrease in grain yield under LN conditions. In conclusion, we selected eight genetic resources that exhibited higher GYP under both NN and LN conditions with higher NPP or NSP. These genetic resources can be considered valuable breeding materials for the adaptation of plants to nitrogen deficiency.

• Journal of the Korean Society of Radiology
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• v.85 no.3
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• pp.581-595
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• 2024

Purpose The present study aimed to investigate the frequency and extent of compensatory common bile duct (CBD) dilatation after cholecystectomy, assess the time between cholecystectomy and CBD dilatation, and identify potentially useful CT findings suggestive of obstructive CBD dilatation. Materials and Methods This retrospective study included 121 patients without biliary obstruction who underwent multiple CT scans before and after cholecystectomy at a single center between 2009 and 2011. The maximum short-axis diameters of the CBD and intrahepatic duct (IHD) were measured on each CT scan. In addition, the clinical and CT findings of 11 patients who were initially excluded from the study because of CBD stones or periampullary tumors were examined to identify distinguishing features between obstructive and non-obstructive CBD dilatation after cholecystectomy. Results The mean (standard deviation) short-axis maximum CBD diameter of 121 patients was 5.6 (± 1.9) mm in the axial plane before cholecystectomy but increased to 7.9 (± 2.6) mm after cholecystectomy (p < 0.001). Of the 106 patients with a pre-cholecystectomy axial CBD diameter of < 8 mm, 39 (36.8%) showed CBD dilatation of ≥ 8 mm after cholecystectomy. Six of the 17 patients with long-term (> 2 years) serial follow-up CT scans (35.3%) eventually showed a significant (> 1.5-fold) increase in the axial CBD diameter, all within two years after cholecystectomy. Of the 121 patients without obstruction or related symptoms, only one patient (0.1%) showed IHD dilatation > 3 mm after cholecystectomy. In contrast, all 11 patients with CBD obstruction had abdominal pain and abnormal laboratory indices, and 81.8% (9/11) had significant dilatation of the IHD and CBD. Conclusion Compensatory non-obstructive CBD dilatation commonly occurs after cholecystectomy to a similar extent as obstructive dilatation. However, the presence of relevant symptoms, significant IHD dilatation, or further CBD dilatation 2-3 years after cholecystectomy should raise suspicion of CBD obstruction.

• Journal of the Korean Society of Radiology
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• v.85 no.3
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• pp.618-630
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• 2024

Purpose To compare the efficacy and safety of radiofrequency ablation (RFA) and ethanol ablation (EA) followed by RFA in treating mixed cystic and solid thyroid nodules. Materials and Methods We included 243 nodules from 243 patients who underwent RFA for mixed cystic and solid benign nodules. The nodules were divided into two groups (RFA alone and EA + RFA). We evaluated volume reduction rate (VRR), therapeutic success rate, improvement in symptomatic and cosmetic issues, complications, and adverse effects. Results The RFA group included 204 patients, and the EA + RFA group included 39 patients. The long-term success rates in the RFA only and EA + RFA groups were 90.2% and 97.4%, respectively. The mean VRR at the last follow-up in the RFA and EA + RFA groups were 81.6% and 87.2%, respectively. Therapeutic results were similar in both groups at the last followup. Cosmetic and symptomatic problems markedly improved in both groups. No major complications were observed. Conclusion Both RFA alone and EA + RA are safe and effective methods for treating mixed cystic and solid thyroid nodules, although EA + RFA is slightly more effective.