Purpose: To investigate the incidence of tuberculosis (TB) in healthcare workers (HCWs) with positive interferon-gamma release assay (IGRA) results based on chest X-ray (CXR) and CT findings and determine the role of imaging in the diagnosis of TB. Materials and Methods: Among 1976 hospital personnel screened for TB using IGRA, IGRApositive subjects were retrospectively investigated. Clustered nodular and/or linear streaky opacities in the upper lung zone were considered positive on CXR. The CT findings were classified as active, indeterminate, inactive, or normal. The active or indeterminate class was considered CT-positive. Results: IGRA was positive in 255 subjects (12.9%). CXR and CT were performed in 249 (99.2%) and 113 subjects (45.0%), respectively. CXR- and CT-positive findings were found in 7 of 249(2.8%) and 9 of 113 (8.0%) patients, respectively. Among the nine CT-positive subjects, active and indeterminate TB findings were found in 6 (5.3%) and 3 (2.7%) patients, respectively. Microbiological tests, including acid-fast bacilli staining, culture, and polymerase chain reaction for TB, were negative in all nine CT-positive subjects. Empirical anti-TB medications were administered to 9 CT-positive subjects, and 3 of these nine subjects were CXR-negative for pulmonary TB. Conclusion CT helped diagnose asymptomatic TB in IGRA-positive HCWs.

BACKGROUND/AIMS: Fragmented care in nephrology can cause treatment delays. Nephrologists are qualified to perform vascular access-related procedures because they understand the pathophysiology of renal disease and perform physical examination for vascular access. We compared treatment delays associated with tunneled hemodialysis catheter (TDC) placement between interventional radiologists and nephrologists. METHODS: We collected data by radiologists from January 1, 2011 through December 31, 2011 and by nephrologists from since July 1, 2012 through June 30, 2013. We compared the duration from the hemodialysis decision to TDC placement (D-P duration) and hemodialysis initiation (D-H duration), catheter success and the complication rate, and the frequency and the usage time of non-tunneled hemodialysis catheters (NDCs) before TDC placement. RESULTS: The study analyzed 483 placed TDCs: 280 TDCs placed by radiologists and 203 by nephrologists. The D-P durations were 319 minutes (interquartile range [IQR], 180 to 1,057) in the radiologist group and 140 minutes (IQR, 0 to 792) in the nephrologist group. Additionally, the D-H durations were 415 minutes (IQR,260 to 1,091) and 275 minutes (IQR, 123 to 598), respectively. These differences were statistically significant (p = 0.00). The TDC success rate (95.3% vs. 94.5%, respectively; p = 0.32) and complication rate (16.2% vs. 11%, respectively; p = 0.11) did not differ between the groups. The frequency (24.5 vs. 26%, respectively; p = 0.72) and the usage time of NDC (8,451 vs. 8,416 minutes, respectively; p = 0.91) before TDC placement were not statistically significant. CONCLUSIONS: Trained interventional nephrologists could perform TDC placement safely, minimizing treatment delays.
Catheters* ; Nephrology ; Physical Examination ; Renal Dialysis* ; Vascular Access Devices

Neurofibromatosis type 1 (NF1), which may occur as an autosom-al dominant disorder, is caused by the absence of neurofibromin protein due to somatic mutations in the NF1 gene, and it has been associated with an increased risk of breast cancer. Herein we describe a family with two women affected by both NF1 and early-onset breast cancer. We evaluated whether the concomitance of NF1 and early-onset breast cancer could be due to disease-causing mutations in both NF1 and BRCA1 gene in a Korean family with clinical features of both NF1 and hereditary breast cancer. Mutation analyses identified nonsense mutations in NF1 and BRCA1 genes. Our findings indicate that an awareness of the possible concomitance of NF1 and BRCA1 gene mutations is important for identifying the genetic origin of early-onset breast cancer in patients with NF1 to achieve early detection of cancers and decrease breast cancer-associated morbidity and mortality in these patients.
Breast ; Breast Neoplasms* ; Codon, Nonsense ; Female ; Genes, BRCA1 ; Genes, Neurofibromatosis 1 ; Germ-Line Mutation* ; Humans ; Mortality ; Neurofibromatosis 1* ; Neurofibromin 1

OBJECTIVE: This study proposes a novel reference standard for hypervascular hepatocellular carcinomas (HCCs), established by cone-beam computed tomography-hepatic arteriography (CBCT-HA) and two-year imaging follow-up, and discusses its clinical implication on tumor staging and understanding the intrahepatic distant recurrence (IDR) in relation to dynamic computed tomography (CT).MATERIALS AND METHODS: In this retrospective study, 99 patients were enrolled, who underwent CBCT-HA during initial chemoembolization for HCC suspected on CT. All patients underwent chemoembolization and regular clinical and imaging follow-up for two years. If IDR appeared on follow-up imaging, initial CBCT-HA images were reviewed to determine if a hypervascular focus pre-existed at the site of recurrence. Pre-existing hypervascular foci on CBCT-HA were regarded as HCCs in initial presentation. Initial HCCs were classified into three groups according to their mode of detection (Group I, detected on CT and CBCT-HA; Group II, additionally detected on CBCT-HA; Group III, confirmed by interval growth). We assessed the influence of CBCT-HA and two-year follow-up on initial tumor stage and calculated the proportion of IDR that pre-existed in initial CBCT-HA.RESULTS: A total of 405 nodules were confirmed as HCCs, and 297 nodules initially pre-existed. Of the initial 297 HCCs, 149 (50.2%) lesions were in Group I, 74 (24.9%) lesions were in Group II, and the remaining 74 (24.9%) lesions were in Group III. After applying CBCT-HA findings, 11 patients upstaged in T stage, and 4 patients had a change in Milan criteria. Our reference standard for HCC indicated that 120 of 148 (81.1%) one-year IDR and 148 of 256 (57.8%) two-year IDR existed on initial CBCT-HA.CONCLUSION: The proposed method enabled the confirmation of many sub-centimeter-sized, faintly vascularized HCC nodules that pre-existed initially but clinically manifested as IDR. Our reference standard for HCC helped in understanding the nature of IDR and the early development of HCC as well as the clinical impact of tumor staging and treatment decision.
Angiography ; Carcinoma, Hepatocellular ; Follow-Up Studies ; Humans ; Methods ; Neoplasm Staging ; Recurrence ; Retrospective Studies

Objective: This study aimed to investigate the feasibility of using artificial intelligence (AI) to identify normal chest radiography (CXR) from the worklist of radiologists in a health-screening environment. Materials and Methods: This retrospective simulation study was conducted using the CXRs of 5887 adults (mean age ± standard deviation, 55.4 ± 11.8 years; male, 4329) from three health screening centers in South Korea using a commercial AI (Lunit INSIGHT CXR3, version 3.5.8.8). Three board-certified thoracic radiologists reviewed CXR images for referable thoracic abnormalities and grouped the images into those with visible referable abnormalities (identified as abnormal by at least one reader) and those with clearly visible referable abnormalities (identified as abnormal by at least two readers). With AI-based simulated exclusion of normal CXR images, the percentages of normal images sorted and abnormal images erroneously removed were analyzed. Additionally, in a random subsample of 480 patients, the ability to identify visible referable abnormalities was compared among AI-unassisted reading (i.e., all images read by human readers without AI), AI-assisted reading (i.e., all images read by human readers with AI assistance as concurrent readers), and reading with AI triage (i.e., human reading of only those rendered abnormal by AI). Results: Of 5887 CXR images, 405 (6.9%) and 227 (3.9%) contained visible and clearly visible abnormalities, respectively. With AI-based triage, 42.9% (2354/5482) of normal CXR images were removed at the cost of erroneous removal of 3.5% (14/405) and 1.8% (4/227) of CXR images with visible and clearly visible abnormalities, respectively. In the diagnostic performance study, AI triage removed 41.6% (188/452) of normal images from the worklist without missing visible abnormalities and increased the specificity for some readers without decreasing sensitivity. Conclusion This study suggests the feasibility of sorting and removing normal CXRs using AI with a tailored cut-off to increase efficiency and reduce the workload of radiologists.

Background: Inactive or old, healed tuberculosis (TB) on chest radiograph (CR) is often found in high TB incidence countries, and to avoid unnecessary evaluation and medication, differentiation from active TB is important. This study develops a deep learning (DL) model to estimate activity in a single chest radiographic analysis. Methods: A total of 3,824 active TB CRs from 511 individuals and 2,277 inactive TB CRs from 558 individuals were retrospectively collected. A pretrained convolutional neural network was fine-tuned to classify active and inactive TB. The model was pretrained with 8,964 pneumonia and 8,525 normal cases from the National Institute of Health (NIH) dataset. During the pretraining phase, the DL model learns the following tasks: pneumonia vs. normal, pneumonia vs. active TB, and active TB vs. normal. The performance of the DL model was validated using three external datasets. Receiver operating characteristic analyses were performed to evaluate the diagnostic performance to determine active TB by DL model and radiologists. Sensitivities and specificities for determining active TB were evaluated for both the DL model and radiologists. Results: The performance of the DL model showed area under the curve (AUC) values of 0.980 in internal validation, and 0.815 and 0.887 in external validation. The AUC values for the DL model, thoracic radiologist, and general radiologist, evaluated using one of the external validation datasets, were 0.815, 0.871, and 0.811, respectively. Conclusion This DL-based algorithm showed potential as an effective diagnostic tool to identify TB activity, and could be useful for the follow-up of patients with inactive TB in high TB burden countries.

Endogenous endophthalmitis secondary to group B Streptococcus (GBS) is extremely rare, particularly in healthy adults. However, the visual prognosis is poor. We report the first South Korean case of GBS infective endocarditis presenting as endogenous endophthalmitis and skin and soft tissue infection. Cultures of blood, vitreous humor, and pus from skin aspirates yielded a penicillin-susceptible serotype V strain of Streptococcus agalactiae. After 6 weeks, the patient completely recovered from GBS infective endocarditis. However, despite early antibiotic treatment and early surgical intervention, the patient's right eye developed phthisis bulbi and was a candidate for evisceration.
Adult* ; Endocarditis* ; Endophthalmitis* ; Humans ; Patient Rights ; Prognosis ; Serogroup ; Skin ; Soft Tissue Infections ; Streptococcus agalactiae* ; Streptococcus* ; Suppuration ; Vitreous Body

Background: Epidemiological data have shown that vitamin D deficiency is highly prevalent in Korea. Genetic factors influencing vitamin D deficiency in humans have been studied in Europe but are less known in East Asian countries, including Korea. We aimed to investigate the genetic factors related to vitamin D levels in Korean people using a genome-wide association study (GWAS). Methods: We included 12,642 subjects from three different genetic cohorts consisting of Korean participants. The GWAS was performed on 7,590 individuals using linear or logistic regression meta- and mega-analyses. After identifying significant single nucleotide polymorphisms (SNPs), we calculated heritability and performed replication and rare variant analyses. In addition, expression quantitative trait locus (eQTL) analysis for significant SNPs was performed. Results: rs12803256, in the actin epsilon 1, pseudogene (ACTE1P) gene, was identified as a novel polymorphism associated with vitamin D deficiency. SNPs, such as rs11723621 and rs7041, in the group-specific component gene (GC) and rs11023332 in the phosphodiesterase 3B (PDE3B) gene were significantly associated with vitamin D deficiency in both meta- and mega-analyses. The SNP heritability of the vitamin D concentration was estimated to be 7.23%. eQTL analysis for rs12803256 for the genes related to vitamin D metabolism, including glutamine-dependent NAD(+) synthetase (NADSYN1) and 7-dehydrocholesterol reductase (DHCR7), showed significantly different expression according to alleles. Conclusion The genetic factors underlying vitamin D deficiency in Korea included polymorphisms in the GC, PDE3B, NADSYN1, and ACTE1P genes. The biological mechanism of a non-coding SNP (rs12803256) for DHCR7/NADSYN1 on vitamin D concentrations is unclear, warranting further investigations.

Background: Because the etiologies of bronchiectasis and related diseases vary significantly among different regions and ethnicities, this study aimed to develop a diagnostic bundle for bronchiectasis in South Korea. Methods: A modified Delphi method was used to develop expert consensus statements on a diagnostic bundle for bronchiectasis in South Korea. Initial statements proposed by a core panel, based on international bronchiectasis guidelines, were discussed in an online meeting and two email surveys by a panel of experts (≥70% agreement). Results: The study involved 21 expert participants, and 30 statements regarding a diagnostic bundle for bronchiectasis were classified as recommended, conditional, or not recommended. The consensus statements of the expert panel were as follows: A standardized diagnostic bundle is useful in clinical practice; diagnostic tests for specific diseases, including immunodeficiency and allergic bronchopulmonary aspergillosis, are necessary when clinically suspected; initial diagnostic tests, including sputum microbiology and spirometry, are essential in all patients with bronchiectasis, and patients suspected with rare causes such as primary ciliary dyskinesia should be referred to specialized centers. Conclusion Based on this Delphi survey, expert consensus statements were generated including specific diagnostic, laboratory, microbiological, and pulmonary function tests required to manage patients with bronchiectasis in South Korea.

Background: Although respiratory tract infection is one of the most important factors triggering acute exacerbation of chronic obstructive pulmonary disease (AE-COPD), limited data are available to suggest an epidemiologic pattern of microbiology in South Korea. Methods: A multicenter observational study was conducted between January 2015 and December 2018 across 28 hospitals in South Korea. Adult patients with moderate-to-severe acute exacerbations of COPD were eligible to participate in the present study. The participants underwent all conventional tests to identify etiology of microbial pathogenesis. The primary outcome was the percentage of different microbiological pathogens causing AE-COPD. A comparative microbiological analysis of the patients with overlapping asthma–COPD (ACO) and pure COPD was performed. Results: We included 1,186 patients with AE-COPD. Patients with pure COPD constituted 87.9% and those with ACO accounted for 12.1%. Nearly half of the patients used an inhaled corticosteroid-containing regimen and one-fifth used systemic corticosteroids. Respiratory pathogens were found in 55.3% of all such patients. Bacteria and viruses were detected in 33% and 33.2%, respectively. Bacterial and viral coinfections were found in 10.9%. The most frequently detected bacteria were Pseudomonas aeruginosa (9.8%), and the most frequently detected virus was influenza A (10.4%). Multiple bacterial infections were more likely to appear in ACO than in pure COPD (8.3% vs. 3.6%, p=0.016). Conclusion Distinct microbiological patterns were identified in patients with moderate-to-severe AE-COPD in South Korea. These findings may improve evidence-based management of patients with AE-COPD and represent the basis for further studies investigating infectious pathogens in patients with COPD.