Differentiation of thyroid nodules on US using features learned and extracted from various convolutional neural networks

Thyroid nodules are a common clinical problem. Ultrasonography (US) is the main tool used to sensitively diagnose thyroid cancer. Although US is non-invasive and can accurately differentiate benign and malignant thyroid nodules, it is subjective and its results inevitably lack reproducibility. Therefore, to provide objective and reliable information for US assessment, we developed a CADx system that utilizes convolutional neural networks and the machine learning technique. The diagnostic performances of 6 radiologists and 3 representative results obtained from the proposed CADx system were compared and analyzed.ope

Artificial Intelligence for Breast Cancer Screening in Mammography (AI-STREAM): A Prospective Multicenter Study Design in Korea Using AI-Based CADe/x

Purpose: Artificial intelligence (AI)-based computer-aided detection/diagnosis (CADe/x) has helped improve radiologists' performance and provides results equivalent or superior to those of radiologists' alone. This prospective multicenter cohort study aims to generate real-world evidence on the overall benefits and disadvantages of using AI-based CADe/x for breast cancer detection in a population-based breast cancer screening program comprising Korean women aged ≥ 40 years. The purpose of this report is to compare the diagnostic accuracy of radiologists with and without the use of AI-based CADe/x in mammography readings for breast cancer screening of Korean women with average breast cancer risk. Methods: Approximately 32,714 participants will be enrolled between February 2021 and December 2022 at 5 study sites in Korea. A radiologist specializing in breast imaging will interpret the mammography readings with or without the use of AI-based CADe/x. If recall is required, further diagnostic workup will be conducted to confirm the cancer detected on screening. The findings will be recorded for all participants regardless of their screening status to identify study participants with breast cancer diagnosis within both 1 year and 2 years of screening. The national cancer registry database will be reviewed in 2026 and 2027, and the results of this study are expected to be published in 2027. In addition, the diagnostic accuracy of general radiologists and radiologists specializing in breast imaging from another hospital with or without the use of AI-based CADe/x will be compared considering mammography readings for breast cancer screening. Discussion: The Artificial Intelligence for Breast Cancer Screening in Mammography (AI-STREAM) study is a prospective multicenter study that aims to compare the diagnostic accuracy of radiologists with and without the use of AI-based CADe/x in mammography readings for breast cancer screening of women with average breast cancer risk. AI-STREAM is currently in the patient enrollment phase. Trial registration: ClinicalTrials.gov Identifier: NCT05024591.ope

A Study on the Effect of Process Management to the Business Performance in Korean Shipping Industries

Korean shipping companies are facing various aspects of difficulties such as an increase of prime cost which is caused by a continuous increase of crew cost, a rising oil price, and a rise of ship price and an increase of risk of exchange rate due to fluctuation. In these circumstances, it is essential to adopt an effective management system which can cope with a change in business environment and improve business performance to get competitive power in the international shipping market. The management system can be established and operated in various ways but it should be coincided with the objective of a company’s establishment and management. Therefore, management system should be operated centering on process to manage interrelated activities systematically. However, most of Korean shipping companies are operating department centered management systems leading to limited roles in achievement of their management objectives. In this point of view, process management, which is emphasized by BPR, six sigma, ISO 9000, ABC, TCM, and SCM in business innovation techniques,suggests important points in establishing and operating management system. Most existing studies were restricted in a grasp of the way or effects of adoption of management system. These studies are limited to the examination of relationship between individual elements in the adopted management system and business performance. The improvement in the management system by examination of causal relationship between each process hasn't been examined yet. Therefore this studies to define core processes affecting business performance and identify causal relationship to raise international competitive power in Korean shipping companies. To achieve the aim of this study this study was carried out as follows: Firstly, pre-examination was made by literature research on characteristic of shipping business and present condition to understand what effects on shipping business performance. Secondly, examination was made on business innovation techniques, which emphasize process management and are adopted by many Korean enterprises,such as BPR, six sigma, ISO 9000, TQM, TCM, and SCM. Literature research was focused to process in the pre-examination. Thirdly, analysis was made on present condition of company’s process management based on result from literature research of documents for management system and, in conclusion, core processes were identified such as management responsibility, shore based personnel management, crew management, ship management, and ship operating management. Finally, analysis was made on the survey research to prove the effects of shipping companies’ process management on business performance and statistical analysis was made to identify mutual relationship between 5 core processes and business performance. This study is summarized as follows: Firstly, five core processes in shipping companies have causal relationshipmutually and they effect on business performance. Also, staffs of Korean shipping companies put an importance in ship operating management, crew management,ship management, shore based personnel management and management responsibility in order. This means that the ship operating management is the process which accepts customers’ demands and realizes them resulting in freight, and other processes mean supporting processes for successful shipping. Also, it implies that for successful ship operating, it is essential to provide with human resources and material resources such as appropriate crew and ships. Secondly, 5 core processes affect more on an increase in profit than cost reduction. According to the result of Kendall’s rating verification, there is a causal relationship as effective orderly in a decrease of accident rate, an increase of ship operation rate, a rise of customer satisfaction, an increase of timely operation rate, a reduction of insurance rate, an increase of sales and net income,and a reduction of operational expenses. Thirdly, 5 core processes affect one after the other to shipping companies’performance. According to this study management of Korean shipping companies are recommended to consider this effect relationship and manage the process in stages to maximize the effect of cost reduction and the effect of profit increase.제1장 서론 = 1 제1절 연구의 배경과 목적 = 1 제2절 연구의 구성 및 방법 = 5 제2장 해운산업의 특성과 현황 = 6 제1절 해운산업의 정의 및 특성 = 6 1. 해운산업의 정의 = 6 2. 해운산업의 특성 = 8 제2절 해운시장의 개념 및 세계해운시장 동향 = 12 1. 정기선시장 = 12 2. 부정기선시장 = 14 제3절 국적외항선사의 현황 = 17 1. 선박확보현황 = 17 2. 선박보유현황 = 18 3. 수출입 해상물동량 및 국적선 수송현황 = 21 4. 선원수급 현황 = 23 5. 해양사고 발생현황 = 25 6. 해양오염 발생현황 = 30 7. 항만국통제(PSC) 검사 = 31 8. ISM CODE 관리현황 = 35 9. 해운기업의 품질비용 관리 현황 = 44 10. 운항원가 분석 = 49 11. 경영실적 분석 = 52 제3장 프로세스 관리에 대한 이론적 배경 및 선행연구 고찰 = 54 제1절 프로세스의 개념 = 54 1. 프로세스의 정의 = 54 2. 프로세스관리의 중요성 = 56 3. 프로세스 관리 = 58 제2절 프로세스에 관한 이론적 배경 및 선행연구 고찰 = 62 1. BPR(Business Process Reengineering) = 63 2. 식스시그마 = 67 3. ISO 9001:2000 = 70 4. TQM(Total Quality Management) = 77 5. ABC(Activity Based Cost) = 80 6. TCM(Target Cost Management) = 87 7. SCM(Supply Chain Management) = 91 제4장 외항선사의 프로세스 관리 = 96 제1절 외항선사의 프로세스 파악 = 96 제2절 외항선사의 핵심프로세스 분석 = 102 제3절 외항선사의 프로세스 관리 = 106 1. 경영책임 = 106 2. 인적자원관리 = 110 3. 선박관리 = 118 4. 운항관리 = 126 제5장 실증분석 = 131 제1절 연구모형 설정과 변수측정 = 131 1. 연구모형과 연구가설 설정 = 131 2. 변수의 조작적 정의와 측정 = 135 제2절 자료수집과 분석방법 = 138 1. 자료수집과 분석방법 = 138 2. 설문문항의 구성 = 139 3. 응답자 일반사항 = 142 제3절 분석결과와 해석 = 146 1. 프로세스요인들의 신뢰성과 타당성검정 = 146 2. 성과변수의 신뢰성과 타당성검정 = 151 3. 구조방정식에 의한 경로분석 결과 = 153 4. 다변량 회귀분석 결과 = 160 5. 가설검정결과의 요약 = 171 제6장 결론 = 175 제1절 연구결과의 요약 = 175 제2절 연구결과의 시사점 = 179 제3절 연구의 한계점과 향후 연구과제 = 18

Selection and Reporting of Statistical Methods to Assess Reliability of a Diagnostic Test: Conformity to Recommended Methods in a Peer-Reviewed Journal

Objective: To evaluate the frequency and adequacy of statistical analyses in a general radiology journal when reporting a reliability analysis for a diagnostic test. Materials and methods: Sixty-three studies of diagnostic test accuracy (DTA) and 36 studies reporting reliability analyses published in the Korean Journal of Radiology between 2012 and 2016 were analyzed. Studies were judged using the methodological guidelines of the Radiological Society of North America-Quantitative Imaging Biomarkers Alliance (RSNA-QIBA), and COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) initiative. DTA studies were evaluated by nine editorial board members of the journal. Reliability studies were evaluated by study reviewers experienced with reliability analysis. Results: Thirty-one (49.2%) of the 63 DTA studies did not include a reliability analysis when deemed necessary. Among the 36 reliability studies, proper statistical methods were used in all (5/5) studies dealing with dichotomous/nominal data, 46.7% (7/15) of studies dealing with ordinal data, and 95.2% (20/21) of studies dealing with continuous data. Statistical methods were described in sufficient detail regarding weighted kappa in 28.6% (2/7) of studies and regarding the model and assumptions of intraclass correlation coefficient in 35.3% (6/17) and 29.4% (5/17) of studies, respectively. Reliability parameters were used as if they were agreement parameters in 23.1% (3/13) of studies. Reproducibility and repeatability were used incorrectly in 20% (3/15) of studies. Conclusion: Greater attention to the importance of reporting reliability, thorough description of the related statistical methods, efforts not to neglect agreement parameters, and better use of relevant terminology is necessary.ope

A Study on the Effects of ISO 9 Series on Service Quality Management for Ship Repair Companies

Ever since the introduction of ISO 9000 Certification System in 1987, many companies have adapted Quality Management System to their operation. A lot of ship repair companies have acquired ISO 9000 certifications in recent years. But there has been little study on whether companies that accepted Quality Management System had good results. Therefore, this study is to grasp the actual situation of companies operating via Quality Management System, by comparing ship repair companies' management systems before and after the acquisition of ISO 9000 Certifications. And in case anything amiss found from Systems, this is to suggest methods to improve the Quality Management System by researching causes of them. To accomplish the object of this study, literature study and field investigation were done simultaneously. For the literature study, searched literature about the service quality, especially service quality of ship repair business and specially studied ISO 9001:2000, lately revised edition. For the field investigation, mainly inquired of ship repair companies, shipping companies and auditors in ISO 9000 certificating body about the effectiveness of Quality Management System they adopted, and analyzed causes of things amiss through questionnaire sheets. As a result of analysis, ship repair companies acquired ISO 9000 certifications for the improvement of service quality, sales and work standardization. With the acquisition of ISO 9000 certifications, they achieved their goals in some sort in service quality improvement and work standardization, but not in sales as they expected. Also it showed that ship repair companies and shipping companies consider the quality as the most important thing in ship repair services. In many cases quality management system documents of ship repair companies don't reflect the real aspects of the repair companies. But, those unsuitable Quality Management System documents are not revised, because people do not fully understand ISO 9000 System documents and are short of time to correct them. Shipping companies, the customers of ship repair companies, consider the service quality and price as the most important thing in choosing ship repair companies, not ISO 9000 certification acquisition. Shipping companies set a high value on companies that operate via Quality Management System, considering being better in service quality and more systematic than other companies. As mentioned above, ship repair companies need to improve Quality Management System consistently for the purpose of quality improvement, productivity increase and customer's satisfaction. Government's authorities and local bodies relating to ISO 9000 Certification System should lead companies to acquire ISO 9000 certifications through positive campaign of publicity and active supports, and finally leading to the national competitiveness.목차 Abstract = I 제1장 서론 = 1 제1절 연구의 배경 및 목적 = 1 제2절 연구의 방법 및 구성 = 2 제2장 선박수리업체의 품질경영에 관한 이론적배경 = 4 제1절 품질에 대한 개념정립 = 4 제2절 서비스 품질의 개념 = 9 제3절 선박수리업체 서비스품질의 특성 = 12 제4절 ISO 9000에 대한 이론적 고찰 = 16 제5절 품질경영시스템의 성과측정 = 24 자료: Robert S. Kaplan & David P. Norton, ibid. pp.174-179. = 26 제3장 ISO 9000 도입에 대한 실태분석 = 29 제1절 설문조항의 구성 및 표집 현황 = 29 제2절 선박수리업체 대상 설문조사의 분석 = 31 제3절 해운회사에 대한 설문조사 분석 = 39 제4절 인증기관의 심사원 대상 설문조사 분석 = 43 제4장 실태분석에 따른 품질경영 개선방안 = 46 제1절 문서화 요구사항 = 46 제2절 경영책임 = 47 제3절 제품실현 = 52 제4절 측정, 분석 및 개선 = 58 제5장 결론 = 62 제1절 연구 결과의 요약 = 62 제2절 연구의 한계 및 향후 연구 방향 = 63 참고문헌 = 65 부록 1 선박수리업체 설문 = 68 부록 2 해운회사 설문 = 74 부록 3 심사원 설문 = 7

Diffusion-Weighted MR Enterography to Monitor Bowel Inflammation after Medical Therapy in Crohn's Disease: A Prospective Longitudinal Study

Objective: To prospectively evaluate the performance of diffusion-weighted imaging (DWI) to monitor bowel inflammation after medical therapy for Crohn's disease (CD). Materials and methods: Before and following 1-2 years of medical therapy, between October 2012 and May 2015, 18 randomly selected adult CD patients (male:female, 13:5; mean age ± SD, 25.8 ± 7.9 years at the time of enrollment) prospectively underwent MR enterography (MRE) including DWI (b = 900 s/mm2) and ileocolonoscopy. Thirty-seven prospectively defined index lesions (one contiguous endoscopy-confirmed inflamed area chosen from each inflamed anatomical bowel segment; 1-4 index lesions per patient; median, 2 lesions) were assessed on pre- and post-treatment MRE and endoscopy. Visual assessment of treatment responses on DWI in 4 categories including complete remission and reduced, unchanged or increased inflammation, and measurements of changes in apparent diffusion coefficient (ΔADC), i.e., pre-treatment-post-treatment, were performed by 2 independent readers. Endoscopic findings and CD MRI activity index (CDMI) obtained using conventional MRE served as reference standards. Results: ΔADC significantly differed between improved (i.e., complete remission and reduced inflammation) and unimproved (i.e., unchanged or increased inflammation) lesions: mean ± SD (× 10-3 mm2/s) of -0.65 ± 0.58 vs. 0.06 ± 0.15 for reader 1 (p = 0.022) and -0.68 ± 0.56 vs. 0.10 ± 0.26 for reader 2 (p = 0.025). DWI accuracy for diagnosing complete remission or improved inflammation ranged from 76% (28/37) to 84% (31/37). A significant negative correlation was noted between ΔADC and ΔCDMI for both readers with correlation coefficients of -0.438 and -0.461, respectively (p < 0.05). Conclusion: DWI is potentially a feasible tool to monitor quantitatively and qualitatively bowel inflammation of CD after medical treatment.ope

Radiomics signature for prediction of lateral lymph node metastasis in conventional papillary thyroid carcinoma

PURPOSE: Preoperative neck ultrasound (US) for lateral cervical lymph nodes is recommended for all patients undergoing thyroidectomy for thyroid malignancy, but it is operator dependent. We aimed to develop a radiomics signature using US images of the primary tumor to preoperatively predict lateral lymph node metastasis (LNM) in patients with conventional papillary thyroid carcinoma (cPTC). METHODS: Four hundred consecutive cPTC patients from January 2004 to February 2006 were enrolled as the training cohort, and 368 consecutive cPTC patients from March 2006 to February 2007 served as the validation cohort. A radiomics signature, which consisted of 14 selected features, was generated by the least absolute shrinkage and selection operator (LASSO) regression model in the training cohort. The discriminating performance of the radiomics signature was assessed in the validation cohort with the area under the receiver operating characteristic curve (AUC). RESULTS: The radiomics signature was significantly associated with lateral cervical lymph node status (p < 0.001). The AUC of its performance in discriminating metastatic and non-metastatic lateral cervical lymph nodes was 0.710 (95% CI: 0.649-0.770) in the training cohort and was 0.621 (95% CI: 0.560-0.682) in the validation cohort. CONCLUSIONS: The present study showed that US radiomic features of the primary tumor were associated with lateral cervical lymph node status. Although their discriminatory performance was slightly lower in the validation cohort, our study shows that US radiomic features of the primary tumor alone have the potential to predict lateral LNM.ope

How to Clearly and Accurately Report Odds Ratio and Hazard Ratio in Diagnostic Research Studies?

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Diagnosis of Thyroid Nodules: Performance of a Deep Learning Convolutional Neural Network Model vs. Radiologists

Computer-aided diagnosis (CAD) systems hold potential to improve the diagnostic accuracy of thyroid ultrasound (US). We aimed to develop a deep learning-based US CAD system (dCAD) for the diagnosis of thyroid nodules and compare its performance with those of a support vector machine (SVM)-based US CAD system (sCAD) and radiologists. dCAD was developed by using US images of 4919 thyroid nodules from three institutions. Its diagnostic performance was prospectively evaluated between June 2016 and February 2017 in 286 nodules, and was compared with those of sCAD and radiologists, using logistic regression with the generalized estimating equation. Subgroup analyses were performed according to experience level and separately for small thyroid nodules 1-2 cm. There was no difference in overall sensitivity, specificity, positive predictive value (PPV), negative predictive value and accuracy (all p > 0.05) between radiologists and dCAD. Radiologists and dCAD showed higher specificity, PPV, and accuracy than sCAD (all p < 0.001). In small nodules, experienced radiologists showed higher specificity, PPV and accuracy than sCAD (all p < 0.05). In conclusion, dCAD showed overall comparable diagnostic performance with radiologists and assessed thyroid nodules more effectively than sCAD, without loss of sensitivity.ope

Assessing Correlation between Two Variables in Repeated Measurements using Mixed Effect Models

Repeated measurements on each variables of interest often arise in bioscience or medical research. We need to account for correlations among repeated measurements to assess the correlation between two variables in the presence of replication. This paper reviews methods to estimate a correlation coefficient between two variables in repeated measurements using the variance-covariance matrix of linear mixed effect models. We analyze acoustic radiation force impulse imaging (ARFI) data to assess correlation between three shear wave velocity (SWV) measurements in liver or spleen and spleen length by ultrasonography. We present how to obtain parameter estimates for the variance-covariance matrix and correlations in mixed effects models using PROC MIXED in SAS.ope