Content-based image retrieval (CBIR) has been heralded as a mechanism to cope with the increasingly larger volumes of information present in medical imaging repositories. However, generic, extensible CBIR frameworks that work natively with Picture Archive and Communication Systems (PACS) are scarce. In this article we propose a methodology for parametric CBIR based on similarity profiles. The architecture and implementation of a profiled CBIR system, based on query by example, atop Dicoogle, an open-source, full-fletched PACS is also presented and discussed. In this solution, CBIR profiles allow the specification of both a distance function to be applied and the feature set that must be present for that function to operate. The presented framework provides the basis for a CBIR expansion mechanism and the solution developed integrates with DICOM based PACS networks where it provides CBIR functionality in a seamless manner.
The benefits of an integrated picture archiving and communication system/radiology information system (PACS/RIS) archive built with open source tools and methods are 2-fold. Open source permits an inexpensive development model where interfaces can be updated as needed, and the code is peer reviewed by many eyes (analogous to the scientific model). Integration of PACS/RIS functionality reduces the risk of inconsistent data by reducing interfaces among databases that contain largely redundant information. Also, wide adoption would promote standard data mining tools—reducing user needs to learn multiple methods to perform the same task. A model has been constructed capable of accepting HL7 orders, performing examination and resource scheduling, providing digital imaging and communications in medicine (DICOM) worklist information to modalities, archiving studies, and supporting DICOM query/retrieve from third party viewing software. The multitiered architecture uses a single database communicating via an ODBC bridge to a Linux server with HL7, DICOM, and HTTP connections. Human interaction is supported via a web browser, whereas automated informatics services communicate over the HL7 and DICOM links. The system is still under development, but the primary database schema is complete as well as key pieces of the web user interface. Additional work is needed on the DICOM/HL7 interface broker and completion of the base DICOM service classes.
A picture archive and communications system (PACS) is a rich source of images and data suitable for creating electronic teaching files (ETF). However, the potential for PACS to support nonclinical applications has not been fully realized: at present there is no mechanism for PACS to identify and store teaching files; neither is there a standardized method for sharing such teaching images. The Medical Image Resource Center (MIRC) is a new central image repository that defines standards for data exchange among different centers. We developed an ETF server that retrieves digital imaging and communication in medicine (DICOM) images from PACS, and enables users to create teaching files that conform to the new MIRC schema. We test-populated our ETF server with illustrative images from the clinical case load of the National Neuroscience Institute, Singapore. Together, PACS and MIRC have the potential to benefit radiology teaching and research.
electronic teaching files; PACS; computer server; Radiological Society of North America; Medical Image Resource Center; medical education
Verifying the integrity of DICOM files transmitted between separate archives (eg, storage service providers, network attached storage, or storage area networks) is of critical importance. The software application described in this article retrieves a specified number of DICOM studies from two different DICOM storage applications; the primary picture archiving and communication system (PACS) and an off-site long-term archive. The system includes a query/retrieve (Q/R) module, storage service class provider (SCP), a DICOM comparison module, and a graphical user interface. The system checks the two studies for DICOM 3.0 compliance and then verifies that the DICOM data elements and pixel data are identical. Discrepancies in the two data sets are recorded with the data elements (tag number, value representation, value length, and value field) and pixel data (pixel value and pixel location) in question. The system can be operated automatically, in batch mode, and manually to meet a wide variety of use cases. We ran this program on a 15% statistical sample of 50,000 studies (7500 studies examined). We found 2 pixel data mismatches (resolved on retransmission) and 831 header element mismatches. We subsequently ran the program against a smaller batch of 1000 studies, identifying no pixel data mismatches and 958 header element mismatches. Although we did not find significant issues in our limited study, given other incidents that we have experienced when moving images between systems, we conclude that it is vital to maintain an ongoing, automatic, systematic validation of DICOM transfers so as to be proactive in preventing possibly catastrophic data loss.
DICOM; file verification and comparison; PACS
With the growing computing capability of mobile phones, a handy mobile controller is developed for accessing the picture archiving and communication system (PACS) to enhance image management for clinicians with nearly no restriction in time and location using various wireless communication modes. The PACS is an integrated system for the distribution and archival of medical images that are acquired by different imaging modalities such as CT (computed tomography) scanners, CR (computed radiography) units, DR (digital radiography) units, US (ultrasonography) scanners, and MR (magnetic resonance) scanners. The mobile controller allows image management of the PACS including display, worklisting, query and retrieval of medical images in DICOM format. In this mobile system, a server program is developed in a PACS Web server which serves as an interface for client programs in the mobile phone and the enterprise PACS for image distribution in hospitals. The application processing is performed on the server side to reduce computational loading in the mobile device. The communication method of mobile phones can be adapted to multiple wireless environments in Hong Kong. This allows greater feasibility to accommodate the rapidly changing communication technology. No complicated computer hardware or software is necessary. Using a mobile phone embedded with the mobile controller client program, this system would serve as a tool for heath care and medical professionals to improve the efficiency of the health care services by speedy delivery of image information. This is particularly important in case of urgent consultation, and it allows health care workers better use of the time for patient care.
Mobile phone; PACS; PDA; filmless; medical images; health care
To meet the educational needs of a medical imaging department with a strong teaching commitment, a teaching file that uses digital data supplied by the institutional picture archiving and communications system (PACS) was required. This teaching file had to be easily used by the end users, have a simple submission process, be able to support multiple users, be searchable on all data fields, and implementing the teaching file must not incur any additional software or hardware costs. The teaching file developed to address this problem takes advantage of the database structure and capabilities of several components included in the commercial PACS installed at the hospital. MS Access is used to seamlessly integrate with the digital imaging and communication in medicine (DICOM) database of a normal work station that is part of the PACS. This integration allows relevant patient and study demographics to be copied from images of interest and then to be stored in a separate database as the back-end of the digital teaching file. When images for a particular teaching file case need to be reviewed, they are automatically retrieved and displayed from the main PACS database using an open application programming interface (API) connection defined on the PACS web server. Utilizing this open API connection means the teaching file contains only the relevant demographic information of each teaching file case; no image data is stored locally. The open API connection allows access to imaging data usually not encountered in a teaching file, allowing more comprehensive imaging case files to be developed by the radiologist. Other advantages of this teaching file design are that it does not duplicate image data, it is small allowing simple ongoing backup, and it can be opened with multiple users accessing the database without compromising data access or integrity.
Electronic teaching files; DICOM; PACS
Purpose: To identify practical issues surrounding delivering digital images from picture archiving and communication systems (PACS) for research and teaching purposes. The complexity of Digital Imaging and Communications in Medicine (DICOM) access methods, security, patient confidentiality, PACS database integrity, portability, and scalability are discussed. A software prototype designed to resolve these issues is described.System Architecture: A six-component, three-tier, client server software application program supporting DICOM query/retrieve services was developed in the JAWA language. This software was interfaced to a large GE (Mt Prospect, IL) Medical Systems clinical PACS at Northwestern Memorial Hospital (NMH).Conclusion: Images can be delivered from a clinical PACS for research and teaching purposes. Concerns for security, patient confidentiality, integrity of the PACS database, and management of the transactions can be addressed. The described software is one such solution for achieving this goal.
As picture archiving and communication systems (PACS) hit the mainstream of projects gaining attention and priority in healthcare organizations, the promise of achieving better operational efficiencies in the radiology department is at the forefront of the financing discussions. Although some positive economic returns have been documented from the early proponents of PACS, most of the PACS installations are still working through operational changes in regards to digital image prefetching to achieve this objective. The lynchpin for achieving the desired operational efficiency is the enabling of an automated, clinically relevant prefetch process for comparison studies from the digital archives. This report explores the solutions deployed at two hospital systems in Minneapolis to utilize a “comparative region of interest” data element to augment the body region information typically available for prefetching in the PACS system. With this information, the prospective PACS implementer will know how to build in their body region requirements up-front in order to maximize their operational efficiency benefits later.
Recently, the digital imaging and communications in medicine (DICOM) standard introduced rules for the encoding, transmission, and storage of the imaging diagnostic report. This medical document can be stored and communicated with the images in picture archiving and communication system (PACS). It is a structured document that contains text with links to other data such as images, waveforms, and spatial or temporal coordinates. Its structure, along with its wide use of coded information, enables the semantic understanding of the data that is essential for the Electronic Healthcare Record deployment. In this article, we present DICOM Structured Report (SR) and discuss its benefits. We show how SR enables efficient radiology workflow, improves patient care, optimizes reimbursement, and enhances the radiology ergonomic working conditions. As structured input significantly alters the interpretation process, understanding all its benefits is necessary to support the change.
Digital Imaging and Communications in Medicine (DICOM); structured report; interpretation; Picture Archiving and Communication System (PACS); Radiology Information System (RIS); Integrating the Healthcare Enterprise (IHE)
The US Department of Veterans Affairs is integrating imaging functionality into the healthcare enterprise using the Digital Imaging and Communication in Medicine (DICOM) standard protocols. The VA’s VistA Hospital Information System (HIS) is installed at all 170 VA medical centers across the country. Image management is supported by the VistA HIS in several ways. Some VA sites have commercial Picture Archiving and Communication Systems (PACS) interfaced to the VistA HIS, while other sites use the direct image acquisition and diagnostic display capabilities of VistA itself. By supporting a small set of DICOM services, VistA can transmit patient and study text data to the image producing modalities and the commercial PACS, and enable images and study data to be transferred back. Images can be displayed on low-cost clinician’s workstations or high-resolution diagnostic quality multi-monitor workstations located within a facility or elsewhere on the healthcare enterprise wide area network.
Interfaces; HIS; RIS; PACS; DICOM; Enterprise Imaging Systems
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.
DICOM; PACS; worklist
The use of clinical imaging modalities within the pharmaceutical research space provides value and challenges. Typical clinical settings will utilize a Picture Archive and Communication System (PACS) to transmit and manage Digital Imaging and Communications in Medicine (DICOM) images generated by clinical imaging systems. However, a PACS is complex and provides many features that are not required within a research setting, making it difficult to generate a business case and determine the return on investment. We have developed a next-generation DICOM processing system using open-source software, commodity server hardware such as Apple Xserve®, high-performance network-attached storage (NAS), and in-house-developed preprocessing programs. DICOM-transmitted files are arranged in a flat file folder hierarchy easily accessible via our downstream analysis tools and a standard file browser. This next-generation system had a minimal construction cost due to the reuse of all the components from our first-generation system with the addition of a second server for a few thousand dollars. Performance metrics were gathered and the system was found to be highly scalable, performed significantly better than the first-generation system, is modular, has satisfactory image integrity, and is easier to maintain than the first-generation system. The resulting system is also portable across platforms and utilizes minimal hardware resources, allowing for easier upgrades and migration to smaller form factors at the hardware end-of-life. This system has been in production successfully for 8 months and services five clinical instruments and three pre-clinical instruments. This system has provided us with the necessary DICOM C-Store functionality, eliminating the need for a clinical PACS for day-to-day image processing.
PACS; DCMTK; DICOM; DICOM workflow; DICOM storage
As the technology of picture archiving and communications systems (PACS) improves and implementation becomes more widespread, the project management of deploying substantially large, multiple-facility systems becomes an integral part of success. A successful deployment requires project support from the initial planning and surveying to the final acceptance, even encompassing support during active use of the PACS. The sharing of information between project stakeholders of a PACS implementation can be daunting at times, but with the flexibility of the worldwide web, this aspect can be eased. This report speaks to the tools and usuability of the worldwide web to disseminate project management information for planning, implementation, and support of any PACS implementation—anywhere. This sharing of knowledge prepares the end user for what will be available for them when the complete systems is in place, allowing for a smoother migration to PACS.
Ultrasound scanning uses the medical imaging format, DICOM, for electronically storing the images and data associated with a particular scan. Large health care facilities typically use a picture archiving and communication system (PACS) for storing and retrieving such images. However, these systems are usually not suitable for managing large collections of anonymized ultrasound images gathered during a clinical screening trial.
We have developed a system enabling the accurate archiving and management of ultrasound images gathered during a clinical screening trial. It is based upon a Windows application utilizing an open-source DICOM image viewer and a relational database. The system automates the bulk import of DICOM files from removable media by cross-validating the patient information against an external database, anonymizing the data as well as the image, and then storing the contents of the file as a field in a database record. These image records may then be retrieved from the database and presented in a tree-view control so that the user can select particular images for display in a DICOM viewer or export them to external media.
This system provides error-free automation of ultrasound image archiving and management, suitable for use in a clinical trial. An open-source project has been established to promote continued development of the system.
Texas Children’s Hospital is a pediatric tertiary care facility in the Texas Medical Center with a large-scale, Digital Imaging and Communications in Medicine (DICOM)-compliant picture archival and communications system (PACS) installation. As our PACS has grown from an ultrasound niche PACS into a full-scale, multimodality operation, assuring continuity of clinical operations has become the number one task of the PACS staff. As new equipment is acquired and incorporated into the PACS, workflow processes, responsibilities, and job descriptions must be revised to accommodate filmless operations. Round-the-clock clinical operations must be supported with round-the-clock service, including three shifts, weekends, and holidays. To avoid unnecessary interruptions in clinical service, this requirement includes properly trained operators and users, as well as service personnel. Redundancy is a cornerstone in assuring continuity of clinical operations. This includes all PACS components such as acquisition, network interfaces, gateways, archive, and display. Where redundancy is not feasible, spare parts must be readily available. The need for redundancy also includes trained personnel. Procedures for contingency operations in the event of equipment failures must be devised, documented, and rehearsed. Contingency operations might be required in the event of scheduled as well as unscheduled service events, power outages, network outages, or interruption of the radiology information system (RIS) interface. Methods must be developed and implemented for reporting and documenting problems. We have a Trouble Call service that records a voice message and automatically pages the PACS Console Operator on duty. We also have developed a Maintenance Module on our RIS system where service calls are recorded by technologists and service actions are recorded and monitored by PACS support personnel. In a filmless environment, responsibility for the delivery of images to the radiologist and referring physician must be accepted by each imaging supervisor. Thus, each supervisor must initiate processes to verify correct patient and examination identification and the correct count and routing of images with each examination.
An archive is a location containing a collection of records, documents, or other materials of historical importance. An integral part of Picture Archiving and Communication System (PACS) is archiving. When a hospital needs to migrate a PACS vendor, the complete earlier data need to be migrated in the format of the newly procured PACS. It is both time and money consuming. To address this issue, the new concept of vendor neutral archive (VNA) has emerged. A VNA simply decouples the PACS and workstations at the archival layer. This is achieved by developing an application engine that receives, integrates, and transmits the data using the different syntax of a Digital Imaging and Communication in Medicine (DICOM) format. Transferring the data belonging to the old PACS to a new one is performed by a process called migration of data. In VNA, a number of different data migration techniques are available to facilitate transfer from the old PACS to the new one, the choice depending on the speed of migration and the importance of data. The techniques include simple DICOM migration, prefetch-based DICOM migration, medium migration, and the expensive non-DICOM migration. “Vendor neutral” may not be a suitable term, and “architecture neutral,” “PACS neutral,” “content neutral,” or “third-party neutral” are probably better and preferred terms. Notwithstanding this, the VNA acronym has come to stay in both the medical IT user terminology and in vendor nomenclature, and radiologists need to be aware of its impact in PACS across the globe.
Archive; content neutral; architecture neutral; archival layer; data migration; DICOM; non-DICOM migration; PACS; PACS neutral; PACS vendor; patient data; third-party neutral; vendor neutral archive; VNA; workstations
Electronic archiving of radiology images over many years will require many terabytes of storage with a need for rapid retrieval of these images. As more large PACS installations are installed and implemented, a data crisis occurs. The ability to store this large amount of data using the traditional method of optical jukeboxes or online disk alone becomes an unworkable solution. The amount of floor space, number of optical jukeboxes, and off-line shelf storage required to store the images becomes unmanageable. With the recent advances in tape and tape drives, the use of tape for long term storage of PACS data has become the preferred alternative. A PACS system consisting of a centrally managed system of RAID disk, software and at the heart of the system, tape, presents a solution that for the first time solves the problems of multi-modality high end PACS, non-DICOM image, electronic medical record and ADT data storage. This paper will examine the installation of the University of Utah, Department of Radiology PACS system and the integration of automated tape archive. The tape archive is also capable of storing data other than traditional PACS data. The implementation of an automated data archive to serve the many other needs of a large hospital will also be discussed. This will include the integration of a filmless cardiology department and the backup/archival needs of a traditional MIS department. The need for high bandwidth to tape with a large RAID cache will be examined and how with an interface to a RIS pre-fetch engine, tape can be a superior solution to optical platters or other archival solutions. The data management software will be discussed in detail. The performance and cost of RAID disk cache and automated tape compared to a solution that includes optical will be examined.
The Sequence Read Archive (SRA) is the largest public repository of sequencing data from the next generation of sequencing platforms including Illumina (Genome Analyzer, HiSeq, MiSeq, .etc), Roche 454 GS System, Applied Biosystems SOLiD System, Helicos Heliscope, PacBio RS, and others.
SRAdb is an attempt to make queries of the metadata associated with SRA submission, study, sample, experiment and run more robust and precise, and make access to sequencing data in the SRA easier. We have parsed all the SRA metadata into a SQLite database that is routinely updated and can be easily distributed. The SRAdb R/Bioconductor package then utilizes this SQLite database for querying and accessing metadata. Full text search functionality makes querying metadata very flexible and powerful. Fastq files associated with query results can be downloaded easily for local analysis. The package also includes an interface from R to a popular genome browser, the Integrated Genomics Viewer.
SRAdb Bioconductor package provides a convenient and integrated framework to query and access SRA metadata quickly and powerfully from within R.
This presentation describes our experience and lessons learned over the first 3 years of developing and operating a filmless picture archiving and communications system (PACS) for all computed tomography (CT), magnetic resonance (MR), ultrasound, and nuclear medicine studies in our hospital. The PACS conforms to the Digital Imaging and Communications in Medicine (DICOM) standard and includes a sophisticated Worldwide Web (WWW)-based interface to complement the regular DICOM services. The PACS has undergone many design modifications from its inception, which have addressed performance, functionality, support, and maintenance issues. The lessons we have learned through making these modifications are described here and may prove to be helpful to anyone planning to deploy a PACS of their own.
While health care facilities recognize the need for dedicated picture archiving and communication system (PACS) staff at the time of the initial implementation of PACS, they often do not plan accordingly for ongoing or increasing PACS support needs as a PACS matures. This article reviews trends in a health care system’s PACS support data over 4 years to show how PACS support needs evolve over time. PACS support items were logged and categorized over this period and were used by the health care system to become more proactive in system support and adjust staffing levels accordingly. This article details how PACS support needs change over the life of a PACS installation and can be used as a model for health care facilities planning for future PACS support needs.
PACS; digital imaging; support
Compliance with the Health Insurance Portability and Accountability Act (HIPAA) requires gathering audit information from picture archiving and communications systems (PACS) regarding evidence trails of human interactions. Until recently, most PACS users have had limited access to auditing information. Access required resources to handle manual inspection of audit logs, and access to proprietary databases was not always available. Some vendors now produce eXtensible Markup Language (XML) audit logs based on certain events occurring in PACS. However, it is up to the user to convert this information into an easily mined data repository supporting compliance and quality control. This process can be handled in multiple ways, which could mean different audit mechanisms depending on the PACS (or other hospital system) used. It is apparent that an organized method of dealing with audit information is needed. This help may be provided within the Integrating the Healthcare Environment (IHE) framework. The IHE initiative defines a set of profiles, actors, and transactions that create common scenarios for particular workflow processes. The Integration Profiles depict security as a fundamental requirement of the framework. Specifically, the Audit Trail and Node Authentication (ATNA) profile defines standards based mechanisms for securely transmitting and storing audit records in a central repository. The data structure defined by the profile provides a number of record types that capture different audit events. A general feasibility study for storing currently available PACS audit information following the profile is defined, and steps to an automated solution are discussed.
Audit; audit trail; IHE; ATNA; NET; XML; Microsoft Access
In order to gain experience with vendor-supplied picture archive and communication system (PACS) products, a Vantage PACS from Lockheed-Martin was installed in a Mayo community medicine practice in Rochester. This practice produces about 45,000 radiology examinations annually. The PACS includes central long- and short-term storage devices, 10 image display workstations, and a dedicated high-speed image distribution network. Digital images are produced using two Fuji computed radiography readers. Custom worklists were created to facilitate efficient system usage. Currently, all radiographic examinations for this practice are acquired digitally, and interpreted and distributed using the PACS. Remote softcopy interpretation via PACS has decreased the turnaround time for both routine and urgent examinations, and has allowed subspecialty interpretation or consultation for pediatric examinations. These results have significantly improved the radiology component of this community medicine practice.
picture archive and communication systems (PACS); clinical applications of PACS; filmless radiology
This article describes the design and implementation of a low-cost image archival and management solution on a radiology network consisting of UNIX, IBM personal computer-compatible (IBM, Purchase, NY) and Macintosh (Apple Computer, Cupertino, CA) work-stations. The picture archiving and communications system (PACS) is modular, scaleable and conforms to the Digital Imaging and Communications in Medicine (DICOM) 3.0 standard for image transfer, storage and retrieval. Image data is made available on soft-copy reporting workstations by a work-flow management scheme and on desktop computers through a World Wide Web (WWW) interface. Data archival is based on recordable compact disc (CD) technology and is automated. The project has allowed the radiology department to eliminate the use of film in magnetic resonance (MR) imaging, computed tomography (CT) and ultrasonography.
PACS; recordable CD; image archival; DICOM 3.0; filmless radiology
Conquest Hospital was a UK regional development site for a pre-Digital Imaging and Communications in Medicine (DICOM) picture archiving and communication system (PACS). The initial system was installed in mid 1992. Identification has been made of data transfer, ergonomic and single point of failure issues in the original PACS, which was called “iLAN.” This has informed respecification of a DICOM/HTML PACS, the first stages of which have been hospital renetworking and installation of new DICOM 3.0 computed radiography/fluorography and computed tomography/magnetic resonance imaging segments. Final PACS elements are at contract stage. Plans are being completed for linkage of PACS to a clinical information system to create a comprehensive electronic patient record system.
The Picture Archiving and Communication System (PACS) market has been transformed by disruptive innovations from the information technology industry. The cost of storage alone has dropped by a factor of 100 within the past 10 years. Improvements in display, processing, and networking have likewise enabled PACS to be a capable replacement for film. The maturity of PACS has permeated the US healthcare industry from large academic hospitals to small outpatient imaging centers. Can PACS continue to be a platform for innovation or has it become a commodity?
PACS; cost analysis; computer hardware