• Journal of the Korean Society of Radiology
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• v.82 no.4
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• pp.1018-1023
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• 2021

A meandering pulmonary vein (MPV) is a rare pulmonary vascular anomaly characterized by an abnormal course of the pulmonary vein draining into the left atrium. We report the case of a 55-year-old female who was diagnosed with a right MPV on pulmonary angiography. Enhanced chest CT revealed a vascular structure with an abnormal course that drained into the right superior pulmonary vein in the right upper lobe, which resembled a pulmonary arteriovenous malformation (AVM). Pulmonary angiography performed to discriminate between an MPV and pulmonary AVM showed no feeding artery, normal parenchymal staining, and drainage to the left atrium via the culprit vessel. Thus, the patient was diagnosed with MPV. When an MPV is difficult to differentiate from other vascular anomalies on enhanced chest CT, pulmonary angiography can be helpful. By recognizing the angiographic findings of an MPV, unnecessary treatment can be prevented.

• Korean Journal of Radiology
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• v.24 no.4
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• pp.324-337
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• 2023

Objective: The objective of this study was to analyze the different brain oxygen metabolism statuses in preeclampsia using magnetic resonance imaging and investigate the factors that affect cerebral oxygen metabolism in preeclampsia. Materials and Methods: Forty-nine women with preeclampsia (mean age 32.4 years; range, 18-44 years), 22 pregnant healthy controls (PHCs) (mean age 30.7 years; range, 23-40 years), and 40 non-pregnant healthy controls (NPHCs) (mean age 32.5 years; range, 20-42 years) were included in this study. Brain oxygen extraction fraction (OEF) values were computed using quantitative susceptibility mapping (QSM) plus quantitative blood oxygen level-dependent magnitude-based OEF mapping (QSM + quantitative blood oxygen level-dependent imaging or QQ) obtained with a 1.5-T scanner. Voxel-based morphometry (VBM) was used to investigate the differences in OEF values in the brain regions among the groups. Results: Among the three groups, the average OEF values were significantly different in multiple brain areas, including the parahippocampus, multiple gyri of the frontal lobe, calcarine, cuneus, and precuneus (all P-values were less than 0.05, after correcting for multiple comparisons). The average OEF values of the preeclampsia group were higher than those of the PHC and NPHC groups. The bilateral superior frontal gyrus/bilateral medial superior frontal gyrus had the largest size of the aforementioned brain regions, and the OEF values in this area were 24.2 ± 4.6, 21.3 ± 2.4, and 20.6 ± 2.8 in the preeclampsia, PHC, and NPHC groups, respectively. In addition, the OEF values showed no significant differences between NPHC and PHC. Correlation analysis revealed that the OEF values of some brain regions (mainly involving the frontal, occipital, and temporal gyrus) were positively correlated with age, gestational week, body mass index, and mean blood pressure in the preeclampsia group (r = 0.361-0.812). Conclusion: Using whole-brain VBM analysis, we found that patients with preeclampsia had higher OEF values than controls.

• Korean Journal of Radiology
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• v.1 no.1
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• pp.25-32
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• 2000

Objective: The purpose of our study was to determine the ability of H-1 MR spectroscopy (MRS) to lateralize the lesion in patients with hippocampal sclerosis. Materials and Methods: Twenty healthy volunteers and 25 patients with intractable temporal lobe epilepsy whose MR imaging diagnosis was unilateral hippocampal sclerosis were included. This diagnosis was based on the presence of unilateral atrophy and/or high T2 signal intensity of the hippocampus. Single-voxel H-1 MRS was carried out on a 1.5-T unit using PRESS sequence (TE, 136 msec). Spectra were obtained from hippocampal areas bilaterally with volumes of interest (VOIs) of 6.0 cm³ and 2.25 cm³ in healthy volunteers, and of either 6.0 cm³ (n = 14) or 2.25 cm³ (n = 11) in patients. Metabolite ratios of NAA/Cho and NAA/Cr were calculated from relative peak height measurements. The capability of MRS to lateralize the lesion and to detect bilateral abnormalities was compared with MR imaging diagnosis as a standard of reference. Results: In healthy volunteers, NAA/Cho and NAA/Cr ratios were greater than 0.8 and 1.0, respectively. In patients, the mean values of these ratios were significantly lower on the lesion side than on the contralateral side, and lower than those of healthy volunteers (p < .05). The overall correct lateralization rate of MRS was 72% (18/25); this rate was lower with a VOI of 6.0 cm³ than of 2.25 cm³ (64% versus 82%, p < .05). Bilateral abnormalities on MRS were found in 24% (6/25) of cases. Conclusion: Although its rate of correct lateralization is low, single-voxel H-1 MRS is a useful and promising diagnostic tool in the evaluation of hippocampal sclerosis, particularly for the detection of bilateral abnormalities. To improve the diagnostic accuracy of H-1 MRS, further investigation, including the use of a smaller VOI and measurement of the absolute amount of metabolites, are needed.

• The Journal of the Acoustical Society of Korea
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• v.43 no.3
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• pp.361-367
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• 2024

Ultrasound in the air is widely used in industry as a measurement technique to prevent abnormalities in the machinery. Recently, the use of airborne ultrasound imaging techniques, which can find the location of abnormalities using an array transducers, is increasing. A beamforming method that uses the phase difference for each sensor is used to visualize the location of the ultrasonic sound source. We exploit a random sparse ultrasonic array and obtain beamforming power distribution on the source in a certain distance away from the array. Conventional beamforming methods inevitably have limited spatial resolution depending on the number of sensors used and the aperture size. A high-resolution ultrasound imaging technique was implemented by applying functional beamforming as a method to overcome the geometric constraints of the array. The functional beamforming method can be expressed as a generalized beam forming method mathematically, and has the advantage of being able to obtain high-resolution imaging by reducing main-lobe width and side lobes. As a result of observation through computer simulation, it was verified that the resolution of the ultrasonic source in the air was successfully increased by functional beamforming using the ultrasonic sparse array.

• Journal of the Korean Society of Radiology
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• v.84 no.1
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• pp.253-262
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• 2023

Purpose To assess the clinicoradiological features of pulmonary cryptococcosis in immunocompetent patients. Materials and Methods This retrospective study included immunocompetent patients who had been diagnosed with pulmonary cryptococcosis on the histopathologic exam and underwent chest CT between January 2008 and November 2019. Imaging features were divided into major imaging patterns, distributions, and ancillary imaging findings. Univariable analysis was performed to evaluate clinicoradiological features according to the presence of serum cryptococcal antigen. Results Thirty-one patients were evaluated (mean age: 60 years, range: 19-78 years). A single nodular lesion confined to a single lobe was the most common imaging pattern (14/31, 45.2%). Serum cryptococcal antigen tests were performed in 19 patients (19/31, 61.3%). The presence of serum cryptococcal antigen was observed in six patients (6/19, 31.6%), all of whom showed a consolidation-dominant pattern. The presence of serum cryptococcal antigen was significantly associated with the consolidationdominant pattern compared to those associated with a nodule-dominant pattern (p = 0.011). Conclusion A combination of CT findings of consolidation and a positive serum cryptococcal antigen test may be helpful for diagnosing pulmonary cryptococcosis in immunocompetent patients.

• Clinical and Experimental Pediatrics
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• v.51 no.1
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• pp.62-66
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• 2008

Purpose : In addition to epileptic seizures (ES), a variety of physiologic, organic and psychogenic disorders can manifest as paroxysmal behavioral events. Paroxysmal nonepileptic events (PNEs) are quite encountered in infants, young children, and adolescents. In a substantial proportion of cases, a careful history and examination will elucidate their nature. However, in other cases, it is necessary to differentiate PNEs from ES by video-electroencephalographic (EEG) monitoring. We report our experiences with PNEs in a group of children and adolescents who underwent video-EEG monitoring. Methods : From September, 2004 to June, 2006, one hundred thirty patients were monitored in the Pediatric Epilepsy Monitoring Units of Korea University Guro and Ansan hospitals. Their hospital charts were reviewed and video records of these events were analyzed. We observed all patients after video-EEG monitoring for more than 3 months. Results : Typical spells occurred during monitoring in 33 patients, not associated with a seizure pattern on EEG recordings. Two patients were diagnosed as frontal lobe epilepsy on basis of typical semiology and clinical characteristics, so 31 patients were documented to have PNEs finally. The mean age of patients was $7.2{\pm}5.8\;years$. The male to female ratio was 15 (48.4%) to 16 (51.6%). Among 31 patients, fifteen patients had associated disorders such as epilepsy, developmental delay, cerebral palsy, gastric ulcer, attention deficit hyperactivity disorder or depressive disorder. Somatoform disorder and factitious disorder was frequently seen in children more than 5 years old (P<0.05). Psychogenic disorder was more frequent in female (n=6) than in male (n=2) but there was no statistical significance (P>0.05). Conclusion : Our study suggests that video-EEG monitoring is an important diagnostic tool in the evaluation of paroxysmal behavioral events. With correct diagnosis of the PNEs, several unnecessary treatment could be avoided.

• Journal of Chest Surgery
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• v.36 no.7
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• pp.497-503
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• 2003

Pulmonary aspergillosis usually results from the colonization of the existing lung lesions by chronic pulmonary diseases, such as tuberculosis. Most cases of pulmonary aspergilloma have been treated surgically for many years because it is a potentially life-threatening disease causing massive hemoptysis. Here we reviewed our results from the last 10 years. Material and Method: We reviewed 31 cases surgically treated from Aug. 1992 to Jul. 2002. retrospectively. This investigation is designed to illustrate the peak age incidence, sex ratio, chief complaints, preoperative study, anatomic location of operative site, postoperative pathologic finding and postoperative complications. Result: The peak age Incidence laid in the 3rd and 4th decade of 20 cases (64.5%). The most common complaint was hemoptysis in 27 cases (87.1%). The 31 cases had a history of treatment with anti-tuberculous drugs under impression of pulmonary tuberculosis. The 19 cases (61.3%) showed the so-called “Air-meniscus sign” on the preoperative chest X-ray. In the 31 cases (100%) on the chest computed tomography. as a preoperative diagnostic modality, positivity was shown in 37.9%, 83.3% was shown on the fungus culture of sputum for Aspergillus, serum immunodiffusion test for A. fumigatus, respectively. The anatomical location of aspergilloma was mainly in the upper lobe in 19 cases (61.3%) and the majority of cases were managed by lobectomy. The postoperative pathologic findings showed that 31 cases (100%) were combined with tuberculosis. The postoperative complications include empyema, prolonged air leakage, remained dead space, postoperative bleeding and these numbers of cases is 3 cases (9.7%), 2 cases (6.45%), 2 cases (6.45%), 1 case (3.23%), respectively. one case was died postoperatively due to massive beeding, and asphyxia. Conclusion: Compared with the previous study, there is no significant difference in results. Preoperative chest computed tomography and immunodiffusion test were more commonly available and showed high positivity. Operations often became technically difficult because of pleural space obliteration, indurated hilar structures, and poor expansion of the remaining lung, which were more prominent in the patients with complex aspergillosis. In such cases, medical treatments and interventional procedures like bronchial artery embolization are preferred. However, cavernostomy is also recommanded with few additional morbidity because of its relatively less invassiveness. Early surgical intervention is the recommended management for patients with simple aspergilloma considering the Row surgical mortality and morbidity in recent days.

• Journal of the Ergonomics Society of Korea
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• v.35 no.4
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• pp.293-305
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• 2016

Objective: This study aims to measure cognitive load levels by analyzing the EEG of Koreans and foreigners, when they read a Korean text with care selected by level from the grammar and vocabulary aspects, and compare the cognitive load levels through quantitative values. The study results can be utilized as basic data for more scientific approach, when Korean texts or books are developed, and an evaluation method is built, when the foreigners encounter them for learning or an assignment. Background: Based on 2014, the number of the foreign students studying in Korea was 84,801, and they increase annually. Most of them are from Asian region, and they come to Korea to enter a university or a graduate school in Korea. Because those foreign students aim to learn within Universities in Korea, they receive Korean education from their preparation for study in Korea. To enter a university in Korea, they must acquire grade 4 or higher level in the Test of Proficiency in Korean (TOPIK), or they need to complete a certain educational program at each university's affiliated language institution. In such a program, the learners of the Korean language receive Korean education based on texts, except speaking domain, and the comprehension of texts can determine their academic achievements in studying after they enter their desired schools (Jeon, 2004). However, many foreigners, who finish a language course for the short-term, and need to start university study, cannot properly catch up with university classes requiring expertise with the vocabulary and grammar levels learned during the language course. Therefore, reading education, centered on a strategy to understand university textbooks regarded as top level reading texts to the foreigners, is necessary (Kim and Shin, 2015). This study carried out an experiment from a perspective that quantitative data on the readers of the main player of reading education and teaching materials need to be secured to back up the need for reading education for university study learners, and scientifically approach educational design. Namely, this study grasped the difficulty level of reading through the measurement of cognitive loads indicated in the reading activity of each text by dividing the difficulty of a teaching material (book) into eight levels, and the main player of reading into Koreans and foreigners. Method: To identify cognitive loads indicated upon reading Korean texts with care by Koreans and foreigners, this study recruited 16 participants (eight Koreans and eight foreigners). The foreigners were limited to the language course students studying the intermediate level Korean course at university-affiliated language institutions within Seoul Metropolitan Area. To identify cognitive load, as they read a text by level selected from the Korean books (difficulty: eight levels) published by King Sejong Institute (Sejonghakdang.org), the EEG sensor was attached to the frontal love (Fz) and occipital lobe (Oz). After the experiment, this study carried out a questionnaire survey to measure subjective evaluation, and identified the comprehension and difficulty on grammar and words. To find out the effects on schema that may affect text comprehension, this study controlled the Korean texts, and measured EEG and subjective satisfaction. Results: To identify brain's cognitive load, beta band was extracted. As a result, interactions (Fz: p =0.48; Oz: p =0.00) were revealed according to Koreans and foreigners, and difficulty of the text. The cognitive loads of Koreans, the readers whose mother tongue is Korean, were lower in reading Korean texts than those of the foreigners, and the foreigners' cognitive loads became higher gradually according to the difficulty of the texts. From the text four, which is intermediate level in difficulty, remarkable differences started to appear in comparison of the Koreans and foreigners in the beginner's level text. In the subjective evaluation, interactions were revealed according to the Koreans and foreigners and text difficulty (p =0.00), and satisfaction was lower, as the difficulty of the text became higher. Conclusion: When there was background knowledge in reading, namely schema was formed, the comprehension and satisfaction of the texts were higher, although higher levels of vocabulary and grammar were included in the texts than those of the readers. In the case of a text in which the difficulty of grammar was felt high in the subjective evaluation, foreigners' cognitive loads were also high, which shows the result of the loads' going up higher in proportion to the increase of difficulty. This means that the grammar factor functions as a stress factor to the foreigners' reading comprehension. Application: This study quantitatively evaluated the cognitive loads of Koreans and foreigners through EEG, based on readers and the text difficulty, when they read Korean texts. The results of this study can be used for making Korean teaching materials or Korean education content and topic selection for foreigners. If research scope is expanded to reading process using an eye-tracker, the reading education program and evaluation method for foreigners can be developed on the basis of quantitative values.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.13 no.1
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• pp.76-84
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• 2002

Objectives：This study was conducted to investigate the effect of oxygen on attention and memory functions in healthy adolescents. Methods：The participant subjects were recruited from local advertisement. All subjects are students attending ordinary middle and high school. Their degree of achievement was average or below average. Before the study, its nature and purpose were fully explained to the patients and their parents, and a written informed consent was obtained from each child's parent and a written assent from each child for entire the procedure. The Ethics Committee and Clinical Research Committee of Gyeongsang National University Hospital approved the protocol. For baseline assessment, all subjects received tests for attention and memory. All tests were conducted by a certified psychologist. Stroop test, continuous performance test and trail making test A and B were used for evaluation of attention. As memory tests, we used memory assessment scale(MAS), standardized memory assessment tools. Ten to fourteen days after initial assessments, same tests was applied to the same subjects after prior 5 minute oxygen inhalation. Results：1) Attention test：Improved performances in trail making part B, and stroop test were found in normobaric oxygen inhalation group compared to air inhalation group. Improved reaction time in those tests seemed to reflect the enhanced executive prefrontal activity. 2) Memory test：More words and digits memorization were found in short-term memory subscale score in MAS in oxygen inhalation group compared to air inhalation group. This finding suggested the improved working memory function after oxygen inhalation. Conclusion：Though interpreted cautiously, these results suggested that normobaric oxygen inhalation could enhance executive function and working memory of prefrontal lobe. Further study, however, should be performed to investigate the mechanism of effects of oxygen on cognitive enhancement.

• Tuberculosis and Respiratory Diseases
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• v.60 no.5
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• pp.532-539
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• 2006

Background : The incidence of pulmonary tuberculosis has been reducing, but endobronchial tuberculosis continues to be a signigicant heath problem. We performed prospectively bronchoscopy in patients diagnosed with pulmonary tuberculosis in order to evaluate the frequency of endobronchial tuberculosis and its related findings. Follow-up bronchoscopy was also performed after treatment to evaluate the incidence of endobronchial complications such as stenosis and remaining lesions. Methods : From January, 1999 to December, 2003, bronchoscopy was performed on patients newly diagnosed with pulmonary tuberculosis. Results : 458 patients were enrolled in this study, out of 699 patients with pulmonary tuberculosis from 1999 to 2003. 234(51%) had endobronchial tuberculosis. The frequency was 40.3% in males and 66.3% in females, The most common symptom was nonspecific cough and sputum, and the main radiologiy finding was patchy infiltration. The most common subtype of endobronchial tuberculosis was the edema-hyperemic form. The right lung was involved more frequently than the left, and the left upper lobe was the most commonly involved site. 58 patients underwent follow-up bronchoscopy and most of been cured without major sequels. However, 8 patients had a stenosis of trachea and main bronchus, and 6 patients had still had endobronchial lesions. Therefore the treatment was prolonged for 3 months. Conclusion : Endobronchial tuberculosis of pulmonary tuberculosis has been remained of high incidence. bronchoscopic and follow-up bronchoscopy examination needs to evaluate the incidence of endobronchial tuberculosis and its related findings and major complication despite of treatment.