Integration of Temporal Subtraction and Nodule Detection System for Digital Chest Radiographs into Picture Archiving and Communication System (PACS): Four-year Experience

Since May 2002, temporal subtraction and nodule detection systems for digital chest radiographs have been integrated into our hospital’s picture archiving and communication systems (PACS). Image data of digital chest radiographs were stored in PACS with the digital image and communication in medicine (DICOM) protocol. Temporal subtraction and nodule detection images were produced automatically in an exclusive server and delivered with current and previous images to the work stations. The problems that we faced and the solutions that we arrived at were analyzed. We encountered four major problems. The first problem, as a result of the storage of the original images’ data with the upside-down, reverse, or lying-down positioning on portable chest radiographs, was solved by postponing the original data storage for 30 min. The second problem, the variable matrix sizes of chest radiographs obtained with flat-panel detectors (FPDs), was solved by improving the computer algorithm to produce consistent temporal subtraction images. The third problem, the production of temporal subtraction images of low quality, could not be solved fundamentally when the original images were obtained with different modalities. The fourth problem, an excessive false-positive rate on the nodule detection system, was solved by adjusting this system to chest radiographs obtained in our hospital. Integration of the temporal subtraction and nodule detection system into our hospital’s PACS was customized successfully; this experience may be helpful to other hospitals.     

Determining the View of Chest Radiographs

Automatic identification of frontal (posteroanterior/anteroposterior) vs. lateral chest radiographs is an important preprocessing step in computer-assisted diagnosis, content-based image retrieval, as well as picture archiving and communication systems. Here, a new approach is presented. After the radiographs are reduced substantially in size, several distance measures are applied for nearest-neighbor classification. Leaving-one-out experiments were performed based on 1,867 radiographs from clinical routine. For comparison to existing approaches, subsets of 430 and 5 training images are also considered. The overall best correctness of 99.7% is obtained for feature images of 32 × 32 pixels, the tangent distance, and a 5-nearest-neighbor classification scheme. Applying the normalized cross correlation function, correctness yields still 99.6% and 99.3% for feature images of 32 × 32 and 8 × 8 pixel, respectively. Remaining errors are caused by image altering pathologies, metal artifacts, or other interferences with routine conditions. The proposed algorithm outperforms existing but sophisticated approaches and is easily implemented at the same time.     

基于病案的教学查房结合PACS在影像科医师培养中的应用

目的探讨在影像科医师培养中,基于病案(CBL)的教学查房结合医学影像存储与通讯系统(PACS)对医师影像诊断能力培养的价值。方法对2018年在北京大学第三医院放射科轮转CT的41名培训医师,应用PACS对其进行CBL教学查房,对照组为2017年轮转CT的39名培训医师(未进行CBL教学)。从PACS随机抽取每名医师书写的10份报告(报告时间为培训最后1个月),对开展CBL教学前后培训医师的报告书写质量评分并计算优良率。评分标准包括病灶征象描述全面准确、报告内容条理清晰规范、诊断结论逻辑清晰合理、能回答临床提出的问题、提出的下一步诊疗建议合理准确以及无漏诊。同时采用调查问卷的方式评价培训医师对CBL教学查房的主观感受,包括全面系统的认识疾病、提高临床思维能力、读片能力和学习兴趣、PACS对学习的帮助5方面,采用百分比表示。结果1)进行CBL教学查房后,培训医师报告质量评分提高(P<0.01)。2)培训医师对调查问卷5方面满意率分别为90.2%、68.3%、80.5%、75.6%和80.5%。结论应用PACS进行CBL教学查房是培养影像科医师诊断能力的有效方法。     

The design and development of a physician-oriented PACS for the enhancement of e-hospital facilities

Recent advancements in modern medical diagnoses have required a huge increase of the use of equipment such as CT and ultrasound machines. Correspondingly, the storage and dissemination of these medical images have become an important issue to medical professionals. Unfortunately, management of these images has traditionally been slow and cumbersome. With the prevalence of the personal computer, however, along with increased network bandwidth, it is now possible to handle this information electronically as well as wirelessly. The Picture Archiving and Communication System (PACS) is at the forefront of this revolution. Yet, commercially available PACS software is generally prohibitively expensive for hospitals with limited financial resources. A dilemma among many hospitals is deciding how to acquire and implement the proper PACS system without unduly affecting the budget. In this paper, a full function, efficient, and economical PACS system is presented as a viable, non-compromising option for many small and medium-sized hospitals. This system, designed and developed mainly by the physicians and technicians of Puli Christian Hospital (PCH), with the assistance from academia, allows for customization to fit the needs of individual hospitals. This system can be used as the foundation of a hospital's health information infrastructure and to enhance e-hospital service.     

PACS诊断工作站匹配小型DSA在介入治疗中的应用

目的 探讨PACS诊断工作站与小型DSA匹配在介入治疗中的应用价值。方法 PACS诊断工作站通过视频采集一转换方式采集岛津公司的WHA-50N／S小型DSA的PH-DSA方式获得的视频图像，使用DIGOM 3．0国际标准。对采用该系统检查治疗的67例图像资料进行分析，评价该工作站的使用效能。结果 将PACS诊断工作站与小型DSA相接后，将原来的PH-DSA视频图像转变为10～25帧／S的数字DSA图像，可上传输至PACS，达到资料共享。提高了图像后处理的功能。应用该系统获得的数字图像能够保持原设备的清晰程度，无明显失真，可以显示1～2mm的3～4级血管。结论采用小型DSA与PACS诊断工作站相匹配，可以为介入治疗的开展提供可靠的保障。     

Evaluation of the Image Quality of Temporal Subtraction Images Produced Automatically in a PACS Environment

The aim of the study is to evaluate the reliable production of temporal subtraction images in a picture archiving and communication system environment and to establish objective criteria for the evaluation of image quality. A total of 117 temporal subtraction chest images (55 in the upright position, 62 in the supine position) were obtained in five consecutive days. In all of these, we confirmed that there were no interval changes on the original images, and cases with diffuse lung disease were excluded. The temporal subtraction images were classified by three chest radiologists into five levels: 5, excellent; 4, good; 3, acceptable; 2, poor; and 1, very poor. The following were examined: (1) the yield of adequate quality of the temporal subtraction images; (2) whether the temporal subtraction images were obtained in the warping or nonwarping mode; and (3) the correlation of the overall subjective image quality with the relative shift angles, relative shift distances, and the standard deviation of gray levels in the temporal subtraction images. The percentages of acceptable temporal subtraction images were 100% and 66% in the upright and supine positions, respectively. Sixteen (26%) of the 62 supine-position images were made in nonwarping mode, whereas all upright images were made in warping mode. Significant correlations were obtained in the relative shift angle (P < 0.05), relative horizontal shift distance (P < 0.05), and standard deviation of gray levels (P < 0.0001). Temporal subtraction images with acceptable image quality were obtained in the upright position. The objective criteria may be useful for the evaluation of image quality.     

Ontology of Gaps in Content-Based Image Retrieval

Content-based image retrieval (CBIR) is a promising technology to enrich the core functionality of picture archiving and communication systems (PACS). CBIR has a potential for making a strong impact in diagnostics, research, and education. Research as reported in the scientific literature, however, has not made significant inroads as medical CBIR applications incorporated into routine clinical medicine or medical research. The cause is often attributed (without supporting analysis) to the inability of these applications in overcoming the “semantic gap.” The semantic gap divides the high-level scene understanding and interpretation available with human cognitive capabilities from the low-level pixel analysis of computers, based on mathematical processing and artificial intelligence methods. In this paper, we suggest a more systematic and comprehensive view of the concept of “gaps” in medical CBIR research. In particular, we define an ontology of 14 gaps that addresses the image content and features, as well as system performance and usability. In addition to these gaps, we identify seven system characteristics that impact CBIR applicability and performance. The framework we have created can be used a posteriori to compare medical CBIR systems and approaches for specific biomedical image domains and goals and a priori during the design phase of a medical CBIR application, as the systematic analysis of gaps provides detailed insight in system comparison and helps to direct future research.     

应用层次分析法和德尔菲法构建医学图像存档与传输系统评估指标体系

目的 应用层次分析法（AHP）和德尔菲法建立医学图像存档与传输系统（PACS）评估指标体系。方法 回溯性检索2003年 ～ 2012年PubMed、Embase、Science Citation Index、Cochrane Library、万方数据、中国知网等6种电子数据库的PACS文献,在文献分析的基础上,邀请医学影像、计算机应用、生物医学工程、PACS项目管理、临床医疗等专业的9名专家咨询,采用德尔菲法建立评估体系的指标框架,采用AHP确定评估体系各级指标权重,并计算下级指标相对于上级指标的组合权重。结果 构建的评估体系包括一级指标5个、二级指标23个。5个一级指标供应商综合能力、产品成熟性与先进性、系统安全性与可靠性、系统准确性和系统性能的权重分别为0.091 7、0.224 7、0.232 6、0.181 0、0.270 0;各级指标权重均满足一致性检验,所得权重是可以接受的;二级指标组合权重按权重大小排序,权重最大的前5位分别是“工作站性能”、“系统存储与影像存档性能”、“影像质量及显示性能”、“数据的完整性”和“数据安全策略”。结论 德尔菲法和APH相结合是建立评估体系的有效方法,同时,这种构建评估体系的方法也为大型设备的招标评估指标的制定提供新思路。     

Integrating learning contexts in a medical informatics program—preparing for the introduction of PACS

This paper analyzes the possibilities to extend learning contexts within a one-year medical informatics educational program (MIP) at a Radiology Department in Sweden¹. The MIP was carried out within a theoretical framework based upon the integration of four learning contexts, which were inspired by Nonaka's theory of organizational knowledge creation. A summary of organizational knowledge creation theory and the ideas behind the learning contexts are presented. The main objective of the study was to investigate what would be the major benefits from the use of various learning contexts in a one-year medical informatics program? The MIP was found to form a basis for better learning conditions by increasing the flexibility, accommodating greater numbers of students as well as offering better possibilities for continuous learning. Evaluation of the MIP revealed that 98% of radiology department staff as compared to 39% of the intensive care unit staff, who had followed the hospital routine program, felt competent enough to independently use the functions of a new medical system. Although there are good reason to believe that the superior confidence for information technology (IT) is due to the integration of learning contexts, it can not be excluded that it may be due to other reasons also.     

Towards a Theory of PACS Deployment: An Integrative PACS Maturity Framework

Owing to large financial investments that go along with the picture archiving and communication system (PACS) deployments and inconsistent PACS performance evaluations, there is a pressing need for a better understanding of the implications of PACS deployment in hospitals. We claim that there is a gap in the research field, both theoretically and empirically, to explain the success of the PACS deployment and maturity in hospitals. Theoretical principles are relevant to the PACS performance; maturity and alignment are reviewed from a system and complexity perspective. A conceptual model to explain the PACS performance and a set of testable hypotheses are then developed. Then, structural equation modeling (SEM), i.e. causal modeling, is applied to validate the model and hypotheses based on a research sample of 64 hospitals that use PACS, i.e. 70 % of all hospitals in the Netherlands. Outcomes of the SEM analyses substantiate that the measurements of all constructs are reliable and valid. The PACS alignment—modeled as a higher-order construct of five complementary organizational dimensions and maturity levels—has a significant positive impact on the PACS performance. This result is robust and stable for various sub-samples and segments. This paper presents a conceptual model that explains how alignment in deploying PACS in hospitals is positively related to the perceived performance of PACS. The conceptual model is extended with tools as checklists to systematically identify the improvement areas for hospitals in the PACS domain. The holistic approach towards PACS alignment and maturity provides a framework for clinical practice.     

胶片集中打印中提高信息识别率的分析与策略

目的 探寻医学影像存储与传输系统(PACS)集中打印中提升胶片信息识别率的有效方法.方法 分析各成像设备胶片布局中四角信息布局对识别率的影响因素;针对不同的影响因素,通过修改设备的四角信息格式、调整胶片格式、优化选片布局、修改放射信息系统存取号(RIS ACCESSION NUMBER)、引入正则表达式的正确性校验以及多次识别等优化方法识别胶片信息.结果 应用此方法对普放检查集中打印系统进行测试,在信息识别的准确性和有效性方面得到了显著的改进.结论 信息识别优化方法提高了胶片的信息识别率,为数字影像和通信标准(DICOM)电子胶片集中打印模式的实施提供了关键技术保障.     

Computerized Analysis of Pneumoconiosis in Digital Chest Radiography: Effect of Artificial Neural Network Trained with Power Spectra

It is difficult for radiologists to classify pneumoconiosis with small nodules on chest radiographs. Therefore, we have developed a computer-aided diagnosis (CAD) system based on the rule-based plus artificial neural network (ANN) method for distinction between normal and abnormal regions of interest (ROIs) selected from chest radiographs with and without pneumoconiosis. The image database consists of 11 normal and 12 abnormal chest radiographs. These abnormal cases included five silicoses, four asbestoses, and three other pneumoconioses. ROIs (matrix size, 32 × 32) were selected from normal and abnormal lungs. We obtained power spectra (PS) by Fourier transform for the frequency analysis. A rule-based method using PS values at 0.179 and 0.357 cycles per millimeter, corresponding to the spatial frequencies of nodular patterns, were employed for identification of obviously normal or obviously abnormal ROIs. Then, ANN was applied for classification of the remaining normal and abnormal ROIs, which were not classified as obviously abnormal or normal by the rule-based method. The classification performance was evaluated by the area under the receiver operating characteristic curve (Az value). The Az value was 0.972 ± 0.012 for the rule-based plus ANN method, which was larger than that of 0.961 ± 0.016 for the ANN method alone (P ≤ 0.15) and that of 0.873 for the rule-based method alone. We have developed a rule-based plus pattern recognition technique based on the ANN for classification of pneumoconiosis on chest radiography. Our CAD system based on PS would be useful to assist radiologists in the classification of pneumoconiosis.     

医学图像后处理研究进展

概要分析和评述了近年来医学图像后处理技术的发展,并主要从图像分割、配准、重建、PACS系统等方面进行了分类综述。     

Development and Evaluation of Different Methods to Assess Download and Display Time of Image Web Systems

Objectives The aim of this study was to develop and verify different methods of measuring time-to-display (TTD) for radiological images with image web systems (IWS). The process should be automatable in order to repeatedly perform a large number of measurements without human interaction. Materials and Methods Three methods were defined and compared with respect to usability, stability, and quality of results. Method 1 was based on Windows 2000 Performance Monitor, whereas method 2 employed phototransistors taped to the screen and connected to a separate PC. A software tool developed for method 3, which used Windows application programming interface (API) function, calls to read the color code assigned to specific pixels on the screen. Results Method 3 proved to be the most reliable and easy to automate. The accuracy is practically equivalent to method 2, but it proved to be far more automatable. Method 1 produced the largest mean error, was easily disturbed, but was also easy to set up and provided additional insights into the system’s architecture especially if combined with method 3. Conclusions To measure the performance of image distribution systems, any of these methods can be used, but method 3 proved to be superior.     

放疗计划系统网络体系的设计与实现

设计并建立一套连接医学影像采集设备(如CTM、RIP、ET等)、放疗计划系统(TPS)及医用加速器等大型设备的的放射治疗网络体系工作环境,更充分地发挥局域网络在放射治疗中的作用。在现有大型医疗设备、TPS及局域网环境的基础上,提出两种具有代表性的TPS网络体系解决方案,并结合各自的特点及实际应用情况对其进行了分析和比较。实践证明,放疗计划系统网络体系的建设推进了放射治疗全过程的数字化、网络化,在更大范围内实现了医疗信息资源的共享,在更大程度上发挥了TPS在肿瘤治疗过程中的作用。     

Foreign Exam Management in Practice: Seamless Access to Foreign Images and Results in a Regional Environment

A challenge for many clinical users is that a patient may receive a diagnostic imaging (DI) service at a number of hospitals or private imaging clinics. The DI services that patients receive at other locations could be clinically relevant to current treatments, but typically, there is no seamless method for a clinical user to access longitudinal DI results for their patient. Radiologists, and other specialists that are intensive users of image data, require seamless ingestion of foreign exams into the picture archiving and communication system (PACS) to achieve full clinical value. Most commonly, a clinical user will depend on the patient to bring in a CD that contains imaging from another location. However, a number of issues can arise when using this type of solution. Firstly, a CD will not provide the clinical user with the full longitudinal record of the patient. Secondly, a CD often will not contain the report associated with the images. Finally, a CD is not seamless, due to the need to manually import the contents of the CD into the local PACS. In order to overcome these limitations, and provide clinical users with a greater benefit related to a patient’s longitudinal DI history, the implementation of foreign exam management (FEM) at the local site level is required. This paper presents the experiences of FEM in practice. By leveraging industry standards and edge devices to support FEM, multiple sites with disparate PACS and radiology information system (RIS) vendors are able to seamlessly ingest foreign exams within their local PACS as if they are local exams.     

Evaluation of a data warehouse in an academic health sciences center

Objectives: The Clinical data repository (CDR) at the University of Virginia Health System is a data warehouse that provides direct access to data for clinical research and effective decision making. We undertook an evaluation of the CDR to understand factors affecting its adoption. Design: We used a theoretical framework that is based on diffusion of innovation theory. Building on validated survey instruments, we developed a questionnaire and conducted interviews of key executive leaders. Fifty-three individuals with logon ids to the CDR completed our questionnaire. Twelve executive leaders were interviewed. Measurements: The outcome variables were the initial and continued use of the CDR. Independent variables included attributes suggested by diffusion theory (i.e. relative advantage, complexity), knowledge and skills expected to correlate with computer usage, and the influence of communication channels. Results: Our overall response rate was 82%. We identified characteristics of users associated with the initial decision to use the CDR. Compatibility with an individual's skills and work style was associated strongly with satisfaction and continued use. Secondly, the importance of organizational culture and the need for data was illuminated by management interviews. Conclusions: We have shown that diffusion of innovation theory can be used to help understand factors contributing to the success of a data warehouse in a healthcare setting. Our results suggest areas for future research and inquiry as the CDR evolves.     

Demonstration of axonal branching of fibres from certain precerebellar nuclei to the cerebellar cortex and nuclei: a retrograde fluorescent double-labelling study in the cat

Summary The projections from certain brain stem precerebellar nuclei to the cerebellar cortex and nuclei have been examined in the cat by using the retrograde fluorescent double-labelling technique. Crystalline Fluoro-Gold was implanted into the left cerebellar nuclei from the contralateral side and rhodamine-B-isothiocyanate was injected into the overlying cerebellar cortex. The inferior olive, the lateral reticular nucleus, and the reticular tegmental pontine nucleus all contained double- as well as single-labelled neurons, and it was concluded that these nuclei have a high number of neurons whose axons branch to both the cerebellar cortex and nuclei. The neurons in the paramedian reticular nucleus and the pontine nuclei proper appear to project only to the cerebellar cortex.     

Papanicolaou stain may not be necessary in majority of head and neck fine‐needle aspirations: Evidence from a correlation study between diff–quik‐based onsite diagnosis and final diagnosis in 287 head and neck fine‐needle aspirations

Fine‐needle aspiration (FNA) is a useful tool for immediate assessment of palpable lesions, especially in the head and neck region. The objective of this study is to evaluate the degree of correlation between Diff–Quik‐based onsite diagnosis (OD) and final diagnosis (FD) and further improve the efficiency of FNA practice. Two hundred and eighty‐seven cytopathologist‐performed FNAs from the head and neck region were evaluated. Number of passes, number and type of slides and correlation (agreement, modified final diagnosis and disagreement) between OD and FD were evaluated. Among 287 FNAs, the average number of passes per FNA case was 2 (range, 1–5&.rpar;). The mean number of slides reviewed per case was 5 including 2 Diff–Quik (D–Q)‐stained slides, 2 Papanicolaou (Pap)‐stained slides, and 1 cell block (CB)/1 cytospin (Cy). 247 of 287 (86%) cases showed agreement between OD and FD. FD on 36 out of 287 cases (12.5%) was slightly modified or refined after reviewing additional slides. A major diagnostic discrepancy was noted in four cases (1.5%), three of which were classified as squamous cell carcinoma on final diagnosis, and confirmed on surgical follow‐up. Accurate diagnosis can be achieved in the majority (86%) of head and neck FNAs based on immediate examination of D–Q stained slides alone. In a small number of cases (12.5%), reviewing additional slides may refine the final diagnosis. In rare cases, especially cystic squamous lesions, Pap‐stained slides appeared to be helpful. It is plausible to use D–Q‐stained slides alone with most head and neck FNAs in order to provide more cost effective and efficient triaging and patient management. Diagn. Cytopathol. 2010;38:846–853. © 2010 Wiley‐Liss, Inc..     

Towards precision medicine in sepsis: a position paper from the European Society of Clinical Microbiology and Infectious Diseases

BackgroundOur current understanding of the pathophysiology and management of sepsis is associated with a lack of progress in clinical trials, which partly reflects insufficient appreciation of the heterogeneity of this syndrome. Consequently, more patient-specific approaches to treatment should be explored.AimsTo summarize the current evidence on precision medicine in sepsis, with an emphasis on translation from theory to clinical practice. A secondary objective is to develop a framework enclosing recommendations on management and priorities for further research.SourcesA global search strategy was performed in the MEDLINE database through the PubMed search engine (last search December 2017). No restrictions of study design, time, or language were imposed.ContentThe focus of this Position Paper is on the interplay between therapies, pathogens, and the host. Regarding the pathogen, microbiologic diagnostic approaches (such as blood cultures (BCs) and rapid diagnostic tests (RDTs)) are discussed, as well as targeted antibiotic treatment. Other topics include the disruption of host immune system and the use of biomarkers in sepsis management, patient stratification, and future clinical trial design. Lastly, personalized antibiotic treatment and stewardship are addressed (Fig. 1).ImplicationsA road map provides recommendations and future perspectives. RDTs and identifying drug-response phenotypes are clear challenges. The next step will be the implementation of precision medicine to sepsis management, based on theranostic methodology. This highly individualized approach will be essential for the design of novel clinical trials and improvement of care pathways.