Picture Archiving And Communication System Environment Research Articles

Cybersecurity Protection for PACS and Medical Imaging: Deployment Considerations and Practical Problems

Cybersecurity is increasingly affecting the healthcare sector. In a recent article, the authors analyzed specific attacks against picture archiving and communications systems (PACS) and medical imaging networks and proposed security measures. This article discusses issues that require consideration when deploying these proposed measures and provides recommendations on how to implement them. Hospitals should deploy virus scanners on systems where permitted, with high priority on devices that are part of the central IT infrastructure of the hospital. They should introduce a systematic management of software updates on operating system, application software and virus scanner level and clarify the provision of security updates for the intended duration of use when purchasing a new device. They should agree with the PACS vendor on a long-term strategy for implementing access rights, and enable encrypted network communication where possible. This requires an agreement on the encryption algorithms to be used, and a public-key infrastructure. For most of these tasks, standards and profiles exist today. There are, however, some gaps: Implementation of cybersecurity measures would be facilitated by integration profiles on certificate and signature management, and access rights in a PACS environment.

Cybersecurity Challenges for PACS and Medical Imaging

Cybersecurity issues have been on the rise for years, increasingly affecting the healthcare sector. In 2019, several attacks have been published that specifically aim at medical network protocols and file formats, in particular digital imaging and communications in medicine. This article describes five attack scenarios on picture archiving and communications systems (PACS) and medical imaging networks: the import of patient data from storage media containing malware, a compromise of the hospital network, malware embedded in digital imaging and communications in medicine images or reports, a malicious manipulation of medical images and a network infiltration of malicious health level seven messages. Prevention and mitigation measures for each of these attacks exist, some of which can be implemented by the system user (e.g., hospital), while others require implementation in the PACS and medical imaging devices by the vendors. In practice, however, many of these are not in common use. What is missing today are PACS network security guidelines for practitioners that support users in keeping their network secure. Furthermore, integrating the healthcare enterprise integration profiles and test tools might be needed to address the deployment of public key infrastructure and digital signatures in the PACS environment.

Development of an automated patient recognition method for chest CT images using a template-matching technique

If patient information, such as identification number or patient name, has been entered incorrectly in a picture archiving and communication system (PACS) environment, the image may be stored in the wrong place. To prevent such cases of misfiling, we have developed an automated patient recognition system for chest CT images. The image database consisted of 100 cases with present and previous chest CT images. A volume of interest (VOI) measuring 40 × 40 pixels was selected from the left lung region, bronchus region, and right lung region. Next, the overall lung region and these three regions in a current chest CT image were used as a template for determining the residual value with the corresponding four regions in previous chest CT images. To ensure separation between the same and different patients, we applied a combined analysis that employed the ruled-based plus artificial neural network (ANN) method. The overall performance of the method developed was examined in terms of receiver operating characteristic (ROC) curves. The performance of the rule-based plus ANN method using a combination of the four regions was higher than obtained using a rule-based method using these four regions separately. The automated patient recognition system using the rule-based plus ANN method achieved an area under the curve (AUC) value of 0.987. This automated patient recognition method for chest CT images is promising for helping to retrieve misfiled patient images, especially in a PACS environment.

Integration of computer-aided diagnosis/detection (CAD) results in a PACS environment using CAD–PACS toolkit and DICOM SR

Picture Archiving and Communication System (PACS) is a mature technology in health care delivery for daily clinical imaging service and data management. Computer-aided detection and diagnosis (CAD) utilizes computer methods to obtain quantitative measurements from medical images and clinical information to assist clinicians to assess a patient's clinical state more objectively. CAD needs image input and related information from PACS to improve its accuracy; and PACS benefits from CAD results online and available at the PACS workstation as a second reader to assist physicians in the decision making process. Currently, these two technologies remain as two separate independent systems with only minimal system integration. This paper describes a universal method to integrate CAD results with PACS in its daily clinical environment. The method is based on Health Level 7 (HL7) and Digital imaging and communications in medicine (DICOM) standards, and Integrating the Healthcare Enterprise (IHE) workflow profiles. In addition, the integration method is Health Insurance Portability and Accountability Act (HIPAA) compliant. The paper presents (1) the clinical value and advantages of integrating CAD results in a PACS environment, (2) DICOM Structured Reporting formats and some important IHE workflow profiles utilized in the system integration, (3) the methodology using the CAD-PACS integration toolkit, and (4) clinical examples with step-by-step workflows of this integration.

A PACS viewer integrated into an electronic medical record: 2 years of experience

The history of PACS is short in years but already long in achievements. The idea of a picture archiving and communication system (PACS) and a filmless hospital was created in the early 1980s. In a PACS environment, images are acquired, read, communicated, and stored digitally [H. Fu, Picture Archiving and Communication System; Textbook/Peking Union Medical College, Chinese Academy of Medical Sciences Press, 1997; Ref. [1]]. This study was performed to evaluate the situation, problem, and healthcare integrating encountered in the implementation of a picture archiving and communication system (PACS) in various clinical settings in the radiology department and hospital in People's Republic of China.

Integrating MIRC-compliant Semiautomated Teaching Files into PACS Work Flow

A Medical Image Resource Center (MIRC)-compliant teaching file system was created that can be integrated into a picture archiving and communication system (PACS) environment. This system models the three-step process necessary for efficient teaching file creation in a PACS environment: (a) identifying and transferring a case quickly and easily during primary interpretation, (b) editing and authoring the case outside of primary interpretation time, and (c) publishing the case locally and via MIRC standard-based mechanisms. Images from interesting cases are e-mailed to the teaching file system from either the PACS workstation or the radiologist's personal computer. Notes and clinical information may be included in the e-mail text to prompt the recollection of case details. Images are automatically extracted from the e-mail and sent to an image repository, and text fields are captured in a database. The World Wide Web-based authoring component provides tools for final authoring of cases and for the manipulation of existing cases. Authors designate access levels for each case, which is then made available locally and, potentially, to the entire MIRC-compliant community. Although this application has not yet been implemented as a departmental solution, it promises to improve and streamline medical education and promote better patient care.

Picture archiving and communication system in China: the development, problem, and integrating strategy with IHE

The history of PACS is short in years but already long in achievements. The idea of a picture archiving and communication system (PACS) and a filmless hospital was created in the early 1980s. In a PACS environment, images are acquired, read, communicated, and stored digitally [H. Fu, Picture Archiving and Communication System; Textbook/Peking Union Medical College, Chinese Academy of Medical Sciences Press, 1997; Ref. [1]]. This study was performed to evaluate the situation, problem, and healthcare integrating encountered in the implementation of a picture archiving and communication system (PACS) in various clinical settings in the radiology department and hospital in People's Republic of China.

Development of an automated patient-recognition method for digital chest radiographs using edge-enhanced images

It is important that all images in a picture archiving and communication system (PACS) environment should be stored in the correct location, e.g., in the proper patient's folder. However, if patient information, such as identification number or patient name, has been entered incorrectly, the image may be stored in the wrong place. We are developing an automated patient recognition method for chest radiographs based on a template-matching technique to prevent such filing errors. To further improve the performance of our method, we investigated the usefulness of a new automated patient-recognition method based on a template-matching technique by using edge-enhanced and smoothed images. We found that the relationship between the correlation values obtained with and without the edge-enhancement technique tended to provide different criteria for identifying correct or incorrect patients. When we combined the two methods to distinguish the images by a rule-based method, 67.1% of wrongly identified patients in our database could be identified as wrongly identified, without any false warnings for correctly identified patients. We consider that this automated method for patient recognition based on edge-enhanced images would be useful in preventing "wrong" images from being stored in a PACS environment.

Integration of a multimedia teaching and reference database in a PACS environment.

In one radiology department, a computerized authoring and editing environment was developed and integrated with the picture archiving and communication systems (PACS) for creation of image-based electronic teaching files to replace a collection of printed film images. This multimedia database and authoring environment allows physicians to create reference databases for teaching and research directly from clinical cases being reviewed on PACS diagnostic workstations. The database engine allows users to generate stand-alone CD-ROMs (compact disks, read-only memory) and World Wide Web-based teaching files. The system is fully compliant with the Digital Imaging and Communications in Medicine (DICOM) standard and supports a large number of standard multimedia image file formats. The focus of the development was on convenience and ease of use of a generic system adaptable to all users. The software was integrated on the PACS workstations to allow users to add new cases to the database at any time and anywhere in the department. A pilot system was implemented in clinical operation, with a central server and several client units.

Designing fault-tolerant distributed archives for picture archiving and communication systems.

Distributed archives in a picture archiving and communication system (PACS) environment can provide added fault tolerance and fail-over capability, as well as increased load capacity at a more economical price than traditional 'high-availability" systems. Systems can be configured with varying levels of fault tolerance, depending on the amount of redundancy desired. There is, however, a direct correlation between the level of hardware redundancy and cost to implement. This presentation details the system design for fault-tolerant distributed archives as well as several options for redundancy, referencing implementation of a fault-tolerant archive system at the University of Utah. The distributed archive system described here is based on Image Devices' image archive software, which can be implemented on multiple individual archive servers in order to distribute archive functionality and operational load. The configuration and implementation of the individual servers together make up the distributed archive system and does not impact the ability of the system to be scaled to meet future requirements. Several implementation and configuration options exist, including the ability for servers to maintain replicated databases containing patient and image information. Thus, each archive can be aware of all information and the location of this information within the distributed archive system. The goal is to produce systems that will still be operational in the event of any single point of failure, ie, a network connection failure between facilities or the failure of a single archive server within the distributed system. During normal operation, workload for image acquisition, image routing and image query requests will be distributed between the archive servers. If the system is deployed in a multifacility environment, each archive server can be configured to be responsible for the acquisition and image distribution management within that server's local facility. If the system is deployed in a single facility environment, load can be distributed evenly between the archive servers based on an understanding of the workload requirements generated be each acquisition and display device in the system. In the event that an archive server fails, other archive servers within the system will have the ability to provide some or all of the failed server's functionality. The degree of fail-over capability is dependent on the archive server's configuration as well as hardware redundancy employed. Three levels of fault-tolerant design can be achieved with this system architecture: (1) duplicate work capability only; (2) duplicate work capability and short-term image cache; (3) duplicate work capability, short-term image cache, and longterm image archival. Using the basic fault-tolerant design above, we have implemented a multifacility distributed archive system at the University of Utah. This system was implemented at a fraction of the cost of true "high-availability" archive architectures yet provides constant up time for the PACS system. If the network connection between the two locations goes down, each site is still fully functional for soft-copy read, as well as image acquisition and distribution. If either of the archive servers goes down, the image sources are redirected to the other archive server. The operational server then handles image distribution for both locations. Access to images in the short-term image cache is available to both archive servers and is not affected by loss of the network connection or remote server. Because there is ony one long-term archive device, the ability to retrieve images from long-term storage is the only function compromised by a network or server failure. By implementing distributed archives in a PACS environment, it is possible to achieve a highly fault-tolerant system without the expense of high-availability hardware and software. The design concepts outlined here can be applied to any PACS system that supports distributed archive functionality.

The performance of general-purpose colour CRT monitors in PACS environment

General-purpose colour cathode ray tube (CRT) monitors are used commonly for image display in personal computer-based picture archiving and communication system (PACS) and telemedicine systems. At present, however, we have not enough information about their performance or reliability for this task. Therefore, we studied the performance of five general-purpose colour CRTs and the changes in their performance in a year. Resolution was measured visually using original digital images. Maximum and minimum luminances were measured at the centre and periphery of the CRTs. Distortion was measured in the centre and periphery using original digital images. All the monitors met their specifications. The inhomogeneity of luminance exceeded 20% and varied across the CRTs. Darker monitors took more time to reach stable luminance levels. The corner brightness seemed to be a good estimator of both performance and distortion in colour monitors.

DICOM modality worklist: an essential component in a PACS environment.

The development and acceptance of the digital communication in medicine (DICOM) standard has become a basic requirement for the implementation of electronic imaging in radiology. DICOM is now evolving to provide a standard for electronic communication between radiology and other parts of the hospital enterprise. In a completely integrated filmless radiology department, there are 3 core computer systems, the picture archiving and communication system (PACS), the hospital or radiology information system (HIS, RIS), and the acquisition modality. Ideally, each would have bidirectional communication with the other 2 systems. At a minimum, a PACS must be able to receive and acknowledge receipt of image and demographic data from the modalities. Similarly, the modalities must be able to send images and demographic data to the PACS. Now that basic DICOM communication protocols for query or retrieval, storage, and print classes have become established through both conformance statements and intervendor testing, there has been an increase in interest in enhancing the functionality of communication between the 3 computers. Historically, demographic data passed to the PACS have been generated manually at the modality despite the existence of the same data on the HIS or RIS. In more current sophisticated implementations, acquisition modalities are able to receive patient and study-related data from the HIS or RIS. DICOM Modality Worklist is the missing electronic link that transfers this critical information between the acquisition modalities and the HIS or RIS. This report describes the concepts, issues, and impact of DICOM Modality Worklist implementation in a PACS environment.

Recommendations for image prefetch or film digitization strategy based on an analysis of an historic radiology image database.

Picture archiving and communications systems (PACS) utilize short- and long-term storage to provide both rapid retrieval and large storage capacity. Owing to the practical limitations imposed on the size of the much faster short-term storage, it is important to use an effective algorithm in the retrieval of comparison images from long to short-term storage. A strategy must be used to maximize the likelihood that the relevant historic images have been previously retrieved into short-term memory. Data were collected with a database consisting of 754 consecutive examinations and 7,723 associated historic studies. The most frequent number of previous examinations was zero (11% of patients). In 45% of cases, no previous matching examinations had been performed. Two basic strategies of image retrieval were evaluated. The first algorithm retrieved the last n studies in chronological order. The second strategy tested was retrieval based on a defined interval of time. This strategy was found to be less efficient. By using the former strategy, a 91% success rate (defined as successful retrieval of the previous matching exam) was achieved with retrieval of only 30% of the prior exams. The second approach required retrieval of 70% of the prior exams to achieve a 90% success rate for the previous matching exam. However, the data from this latter strategy suggest that examinations are often ordered in clusters. Thus, there was found to be a 72% likelihood that a previous matching exam, if present, would available on a PACS after only 1 week of operation, and an 80% chance after only 1 month of operation. The data therefore suggest that digitization of film in a new PACS environment might not be necessary owing to the relatively short period of time required to populate the database with historical studies.

Picture archiving and communications systems (PACS)

Although there has been a recent increase in interest in picture archiving and communication systems (PACS) topics, little has been published to assist the non-technical person in understanding the complexities of the technologies required for a PACS implementation. This issue of Current Problems in Radiology defines each PACS component and explains why each is important in a system design. PACS installations at the University of Florida are used as examples to tie the concepts together. The infrastructure required for PACS consists of the information system interfaces, networks, and databases. Information system interfaces guarantee consistent patient data across all platforms and reduce labor requirements by eliminating duplicate data entry. Data networks move information from the originating location to users around the hospital, clinic, campus, city, or world. In the PACS environment, the data consist of patient and study information as well as images and information about these images. Databases organize the data from multiple sources into a coherent package that can be queried for many different purposes, such as retrieving images, reviewing patient and study information, studying practice statistics, and performing outcomes analysis. PACS components consist of acquisition nodes, archives, and output devices. Acquisition nodes may include “digital modalities” such as CT, MRI, nuclear medicine, and computed radiography (CR), along with devices to convert from analog to digital, such as digitizers and frame grabbers. Options for archives are discussed along with configuration schemes. Output devices include both hard copy (film and paper prints) and soft copy (workstations for display and diagnosis). Finally, a description of the PACS installations at the University of Florida is presented, with comments on some of the difficulties and complexities encountered. A discussion of the cost and benefits of PACS is included, along with a forecast of the future of PACS.

Integration of a voice processor machine in a PACS

The final stage of development of a clinical picture archiving and communication system (PACS) at the University of California at Los Angeles (UCLA) department of radiological sciences consists of building a documentation package of a complete radiological consultation. In this paper, we present the technological aspect of the integration of a digital voice server in our PACS environment. This component improves the timely delivery of the diagnostic report with the images. The interface of this voice system is integrated into the PACS display station. It offers the user the capability to easily dictate and/or listen to radiological reports, while viewing and/or performing image processing operations at the display station.