Purpose: To investigate the flow characteristics using different thresholding methods on a choriocapillaris optical coherence tomography angiography (OCTA) image complemented with a structural En Face image. Methods: The 42 choriocapillaris OCTA images from healthy subjects were obtained with swept-source OCTA device and the 3 × 3-mm area OCTA images were processed with ImageJ. Using a raw choriocapillaris OCTA image and structural En Face image, we adjusted the different structural signal intensity. Then, the raw images and adjusted images were binarized with a global threshold and an auto local threshold using the Phansalkar method at 1- or 2-intercapillary distance. Then, the mean area, number, and size of the flow void, were compared among the images using different thresholding methods. Results: Mean flow void area, number, and size were different according to the different binarization method both in raw and adjusted images (all p < 0.001). The mean flow void area analyzed with global threshold method were well correlated with those with auto local threshold method both in raw and adjusted images (all intraclass correlations, >0.929). Conclusions Flow void features varied according to the different binarization methods but showed good correlation. The flow void characteristics according to the different binarization methods should be considered for the analysis of the choriocapillaris OCTA images complemented with a structural En Face image.

Radon, a source of natural background radiation, has been a subject of extensive studies as a major causative agent of lung cancer at the domestic and international levels. This study investigated and compared domestic and international methods of radon measurement. In the United States, radon is measured through primary and secondary testing, and a similar method is used in Canada. In the United Kingdom, only long-term radon measurements are taken with seasonal adjustments. In the Republic of Korea, both long-term and short-term measurements are taken with only primary testing. Through this study, standards for domestic radon measurement methods and improvement plans could be suggested.
Background Radiation ; Canada ; Great Britain ; Lung Neoplasms ; Methods* ; Radon* ; Republic of Korea ; Seasons ; United States

OBJECTIVES: Perceived stress scale is a self-report inventory to estimate the degree of individual perceived stress in daily life. The aim of this study was to introduce this scale and test the reliability and validity of the Korean version of PSS. METHODS: The total of 154 female hospital workers were included in this study. The survey questionnaires were conducted for demographic information. All participants were required to complete PSS, Hamilton Anxiety scale and Beck Depression Inventory. Reliability and validity studies were conducted and internal consistency was examined. RESULTS: The mean score of the PSS reported in this sample was 20.69+/-4.56. The overall Cronbach's alpha was 0.819, and the test-retest reliability coefficient was 0.66. PSS had a significant positive correlation with the HAM-A(r=0.49, p<0.01), and the BDI(r=0.55, p<0.01). Factor analysis yielded 2 factors with eigenvalues of 3.924 and 2.608, accounting for 65 percent of variance. Factor 1 represented "stress" and factor 2 represented "control of stress". CONCLUSIONS: This study indicates that the PSS is appropriate for estimating the perceived stress levels. These results support the use of PSS in large sections of the population in Korea.
Accounting ; Anxiety ; Depression ; Female ; Humans ; Korea ; Questionnaires ; Reproducibility of Results

BACKGROUND: Oligonucleotide chip technology has proven to be a very useful tool in the rapid diagnosis of infectious disease. Rifampin resistance is considered as a useful marker of multidrug-resistance in tuberculosis. Mutations in the rpoB gene coding β subunit of RNA polymerase represent the main mechanism of rifampin resistance. The purpose of this study was to develop a diagnosis kit using oligonucleotide chip for the rapid and accurate detection of rifampin-resistance in Mycobacterium tuberculosis. METHOD: Tle sequence specific probes for mutations in the rpoB gene were designed and spotted onto the glass slide, oligonucleotide chip. 38 clinical isolates of Mycobacterium were tested. A part of rpoB was amplified, labelled, and hybridized on the oligonucleotide chip with probes. Results were analyzed with a laser scanner. Direct sequencing was done to verify the results. RESULT: The low-density oligonucleotide chip designed to determine the specific mutations in the rpoB gene of M. tuberculosis accurately detected rifampin resistance associated with mutations in 28 clinical isolates. Mutations at codons 531, 526, and 513 were confirmed by direct sequencing analysis. CONCLUSION: Mutant detection using oligonucleotide chip technology is a reliable and useful diagnostic tool for the detection of multidrug-resistance in M. tuberculosis.
Clinical Coding ; Codon ; Communicable Diseases ; Diagnosis ; DNA-Directed RNA Polymerases ; Glass ; Mycobacterium ; Mycobacterium tuberculosis ; Rifampin ; Tuberculosis*

Intracranial dermoid cyst is a rare congenital benign disease, representing less than 0.5% of primary brain tumors. Nevertheless, if ruptured spontaneously or during surgery, it has a poor prognosis due to chemical meningitis. Therefore, it is essential to perform accurate diagnosis and proper treatment. We report an intracranial subdural dermoid cyst that may be misdiagnosed as extracranial or epidural lesion because of extension into the right foramen ovale, and describe the CT and MR imaging findings.
Brain Neoplasms ; Dermoid Cyst* ; Diagnosis ; Foramen Ovale* ; Magnetic Resonance Imaging* ; Meningitis ; Prognosis

E-cigarettes, heat-not-burn (HNB) tobacco, and other new types of tobacco products are emerging in Korea. These products are particularly popular among smokers who are looking for less harmful means of tobacco consumption, and are highly relevant for existing tobacco control policies. E-cigarettes, which are electronic devices designed to allow the user to inhale nicotine as a vapor, are controversial in terms of their safety and effects on smoking cessation, as a variety of harmful substances have been detected in e-cigarette vapor. Due to policy differences in tobacco harm reduction, the regulations on e-cigarettes differ from country to country, and domestic regulations regulate e-cigarettes in a manner similar to conventional cigarettes. In contrast, HNB tobacco was introduced in Korea in June 2017, and is rapidly expanding in the market, as active marketing campaigns seek to communicate to consumers that HNB tobacco use involves no tar and is less harmful to health. However, the World Health Organization and several professional groups have argued that based on independent studies not supported by tobacco companies, HNB tobacco should be regulated in the same way as conventional cigarettes because there is no evidence that HNB tobacco is less harmful. Clinicians need to expand their understanding of new tobacco products so that they can provide appropriate counseling.

E-cigarettes, heat-not-burn (HNB) tobacco, and other new types of tobacco products are emerging in Korea. These products are particularly popular among smokers who are looking for less harmful means of tobacco consumption, and are highly relevant for existing tobacco control policies. E-cigarettes, which are electronic devices designed to allow the user to inhale nicotine as a vapor, are controversial in terms of their safety and effects on smoking cessation, as a variety of harmful substances have been detected in e-cigarette vapor. Due to policy differences in tobacco harm reduction, the regulations on e-cigarettes differ from country to country, and domestic regulations regulate e-cigarettes in a manner similar to conventional cigarettes. In contrast, HNB tobacco was introduced in Korea in June 2017, and is rapidly expanding in the market, as active marketing campaigns seek to communicate to consumers that HNB tobacco use involves no tar and is less harmful to health. However, the World Health Organization and several professional groups have argued that based on independent studies not supported by tobacco companies, HNB tobacco should be regulated in the same way as conventional cigarettes because there is no evidence that HNB tobacco is less harmful. Clinicians need to expand their understanding of new tobacco products so that they can provide appropriate counseling.
Counseling ; Electronic Cigarettes ; Harm Reduction ; Korea ; Marketing ; Nicotine ; Smoking Cessation ; Social Control, Formal ; Tobacco Products ; Tobacco Use ; Tobacco ; World Health Organization

Objective: The Patient Health Questionnaire-4 (PHQ-4) has been used for screening owing to ease of use and brevity.In this study, we developed the Korean version of the PHQ-4 and tested its validity. Methods: One hundred sixteen new adult outpatients at the Department of Psychiatry of the Korea University Ansan Hospital participated in the study. We simultaneously administered other depression/anxiety scales: the Hamilton Rating Scale for Depression, the Hamilton Anxiety Scale, the Beck Depression Inventory, and the Beck Anxiety Inventory. Results: The mean PHQ-4 score was 6.52 (standard deviation = 3.45). Cronbach’s α was 0.792, and the intraclass correlation coefficient of test and 2-week interval retest was 0.827 (p ＜ 0.01). The Pearson correlation coefficients between the PHQ-4 total score and other depression/anxiety scales were all over 0.6. Confirmatory factorial analysis showed acceptable convergent validity and reliability but questionable discriminant validity for some model fit values. Conclusion The Korean version of the PHQ-4 has sufficient internal consistency, test-retest reliability, and construct validity, but its two-factor structure showed incompleteness. However, we suggest that it should be used as a brief screening measure for common psychiatric distress that warrants further detailed assessment, but not to separately assess the severity of depression and anxiety symptoms.

Objective: The pathology of post-traumatic stress disorder (PTSD) is associated with changes in brain structure and function, especially in the amygdala, medial prefrontal cortex, hippocampus, and insula. Survivors of tragic accidents often experience psychological stress and develop post-traumatic stress symptoms (PTSS), regardless of the diagnosis of PTSD. This study aimed to evaluate electroencephalographic changes according to PTSS in victims of a single traumatic event. Methods: This study enrolled 60 survivors of the Sewol ferry disaster that occurred in 2014 from Danwon High School and collected electroencephalographic data through 19 channels twice for each person in 2014 and 2015 (mean 451.88 [standard deviation 25.77] days of follow-up). PTSS was assessed using the PTSD Checklist-Civilian Version (PCL-C) and the participants were divided into two groups according to the differences in PCL-C scores between 2014 and 2015. Electroencephalographic data were converted to three-dimensional data to perform low-resolution electrical tomographic analysis. Results: Significant electroencephalographic changes over time were observed. The group of participants with worsened PCL-C score showed an increased change of delta slow waves in Brodmann areas 13 and 44, with the largest difference in the insula region, compared to those with improved PCL-C scores. Conclusion Our findings suggests that the electrophysiological changes in the insula are associated with PTSS changes.

Objective: The pathology of post-traumatic stress disorder (PTSD) is associated with changes in brain structure and function, especially in the amygdala, medial prefrontal cortex, hippocampus, and insula. Survivors of tragic accidents often experience psychological stress and develop post-traumatic stress symptoms (PTSS), regardless of the diagnosis of PTSD. This study aimed to evaluate electroencephalographic changes according to PTSS in victims of a single traumatic event. Methods: This study enrolled 60 survivors of the Sewol ferry disaster that occurred in 2014 from Danwon High School and collected electroencephalographic data through 19 channels twice for each person in 2014 and 2015 (mean 451.88 [standard deviation 25.77] days of follow-up). PTSS was assessed using the PTSD Checklist-Civilian Version (PCL-C) and the participants were divided into two groups according to the differences in PCL-C scores between 2014 and 2015. Electroencephalographic data were converted to three-dimensional data to perform low-resolution electrical tomographic analysis. Results: Significant electroencephalographic changes over time were observed. The group of participants with worsened PCL-C score showed an increased change of delta slow waves in Brodmann areas 13 and 44, with the largest difference in the insula region, compared to those with improved PCL-C scores. Conclusion Our findings suggests that the electrophysiological changes in the insula are associated with PTSS changes.