With the explosion of digital imaging, long-term digital archives are now holding everything from test results to prescription history. It is only a matter of time before the market demands true, combined data warehousing for all these records. The problem is that many vendors developed custom archiving products that were unique to one specialty, such as radiology or pathology. These legacy products may be based on any operating system. The programming languages and databases, therefore, may not be good candidates for integration into a central, combined data repository. It is important to recognize the archiving needs of the health care enterprise and the unique nature of these specialized systems. How can disparate data be combined to form an accessible master list?

Finding Common Ground

During an effort to consolidate the many different systems found in a typical health care enterprise, it becomes obvious that a single vendor probably cannot provide the focus and expertise needed in each department to put all data into a common form. This problem can be solved using two methods. The data that are needed (and relevant) can be sent to the repository and stored and displayed in the central system. The original system then becomes a pass-through device, and the work that the original vendor did to focus data delivery and develop user tools may be lost. For example, access to digital radiology images is not practical unless some basic tools for image viewing and manipulation are available. Large data sets also may need to be stored and transmitted in compressed form, which poses another concern for a single solution. Can one vendor’s products truly hold, display, and manage the data of the entire enterprise effectively?

Another common integration method is the use of web-enabled applications to launch a clinical page from a master list or server. This is an excellent solution if enough of the installed servers within the enterprise are web enabled. This type of delivery also requires that it be possible to build (or transfer) the link using some type of standardized communication protocol.

Ensuring the security of patient information is a large component of providing web-enabled data access. Security concerns require that only authorized users access information. All of the separate information systems involved, however, may require unique user names and passwords. Many hospital information technology departments have been working to allow a single, enterprise-wide sign-on process in which the user is authenticated once and then moves among systems seamlessly.

IHE: A Key Resource

The Integrating the Healthcare Enterprise (IHE) project1 sponsored by the Radiological Society of North America and the Healthcare Information and Management Systems Society has become a needed resource for health care vendors and users alike, helping them work toward creating a true electronic medical record (EMR). The IHE technical framework is focused on the need for data to flow between systems, allowing each piece both to exist separately and to become a viable part of the EMR. Although radiology and picture archiving and communications systems (PACS) are the initial focus, many health care vendors outside radiology are already taking advantage of this methodology to integrate their systems. There are two standard protocols traditionally used in the health care industry. They are the Digital Imaging and Communications in Medicine (DICOM) and Health Level 7 (HL7) standards. DICOM use has been limited mainly to image transmission and storage for the digital modalities in radiology. DICOM is also used in reporting, and it has capabilities for the transmission of clinical data. “DICOM is currently being used to transmit data among PACS, hospital information systems, and radiology information systems (RIS) systems or broker devices.”

This protocol has not grown much beyond radiology; it requires the entire EMR system to function in both HL7 and DICOM. HL7 has been the standard for communication between clinical databases for many years. It has roots dating back more than 20 years and a proven track record offering the flexibility and diversity needed to bring these systems together. IHE presents a set of integration profiles that offer key points for the successful integration of systems. These are essential when patient information, demographics, and images are referenced by another application.

The seven integration profiles that are vital to the success of the EMR are Scheduled Work Flow, Patient Information Reconciliation, Consistent Presentation Of Images, Presentation of Grouped Procedures, Access to Radiology Information, Key Image Note, Simple Image, and Numeric Reports.2

As facilities search for a way to distribute clinical data quickly and efficiently to departments and providers throughout the community, a web-enabled portal becomes an obvious choice. The combination of security and manageability makes this medium very attractive. The goal, as it relates to radiology, is getting images and results to clinicians. Access to data is also essential for internal hospital users such as surgery, oncology, and pathology departments. Expanding access to external users such as remote clinics, referring physicians, and specialists can have a large effect on patient care and can also make the process of getting results and images (along with laboratory data and other key components of the EMR) streamlined and efficient.

Case Study

Founded in 1886, 335-bed St Cloud Hospital, Centracare Health System, St Cloud, Minn, has been a pioneer in the delivery of health care in central Minnesota. An eMed customer since 1997, St Cloud Hospital was challenged to enhance image storage and distribution to a referring physician base that covers 12 counties. St Cloud has continued to strive for a complete EMR, adding new capabilities and services to its centralized system, which is a clinical data repository (CDR) from Intesys, a division of Spacelabs Medical in Issaquah, Wash. eMed was asked to take on the challenge of bringing image integration and distribution to the Caremaster” CDR.

emed.net has been a very successful image storage and delivery method for several years, offering flexible access to data both within the facility and via Internet. This solution, which uses an ActiveX” plug-in with industry-standard browser software, is both cost effective and portable. This web-based solution truly allows access to images at any time, from anywhere. This type of image distribution has been very popular as part of a progressive approach to teleradiology and clinical image reference.

The initial steps taken at St Cloud in 2000 included the creation of a plan that would allow access to the emed.net server and images. This would bring images to the already large user base of the successful CDR implementation. Initially, the problem was defining how a hyperlink would be built in CDR clinical pages that referenced images located on the eMed server. eMed’s solution to web image distribution allows for both authentication and window isolation (an important means of limiting access to other images and results located on the server). eMed also uses unique pieces of clinical information available globally from the RIS to build the link. This link building means that the CDR system, which gets a demographic feed from the St Cloud RIS, can build the link that permits access to the images. These links are built in real time and embedded in the clinical pages that physicians already use. This data stream is encrypted using a 128-bit browser-based algorithm, ensuring the secure handling of patient information.

This step was, however, only half of the solution. For the system to be viable, emed.net needed to notify the CDR system of the arrival and status of the images. The next step, therefore, was the definition and creation of a functional bidirectional communication framework exhibiting IHE principles.

Message Building

The need to allow a native DICOM machine (such as a PACS or web distribution system) to communicate with systems based primarily on HL7 is not new. HL7-to-DICOM brokers have been available for years to help PACS and RIS communicate. Many RIS vendors have embedded DICOM interfaces in their systems, making brokerless interfaces possible. This is widely regarded as the most difficult and most effective type of interface. eMed has long offered a broker product, so the company was able to choose whether to use it in the web server’s integration with the CDR. Discussions with Intesys and customers at St Cloud led to a design that favored a brokerless solution, both to create an efficient, supportable solution and to make that solution expandable and flexible. This meant that either the CDR system would need a DICOM interface or the eMed solution would need an HL7 interface. Adding an HL7 interface to web-based image distribution seemed a perfect solution that would benefit many facilities that, like St Cloud, needed an integrated EMR solution. With help from Intesys, eMed built an HL7 interface that contained basic HL7 segments and was able to notify the CDR system effectively upon image arrival and upon image deletion from short-term disk storage. This bidirectional interface, combined with modality work-list services and demographic integration between the RIS and PACS/emed.net ensured an accurate, effective addition to the CDR system.

Going Live

With the addition of imaging, the entire system is one step closer to a total EMR. Feedback from users who have experience using the integrated images continues to be positive and indicates that integration has improved efficiency and quality of care. The system has been running for more than a year and is commonly cited by eMed as an example of how integration should be done. The process involved a cooperative approach to integration. Several key factors led to its success. Expectations were clear, with full definition of what was to be done and who would do it. Functionality was documented; a written technical and work-flow design framework was agreed to by all parties. Goals and benchmarks were attainable and were unchanged once they had been set. Full, frequent communication was promoted by status meetings that were open and productive. A phased approach was used, with parts of the system being implemented as they became available. This permitted problems to be solved before live tests of the system began. The final step of implementation was effective real-world testing, in which the Internet and servers were used to exchange messages between systems.

This type of solution is one that benefits St Cloud Hospital, Intesys, and eMed. The role of radiology in the EMR is evolving as technology and standards make integration projects like that at St Cloud hospital possible. The needs of this market make it necessary for all health care vendors to approach similar projects with open minds.

Dave Tomczak is director, Systems Engineering and Services, eMed Technologies, Burlington, Mass.


  1. IHE: Integrating the Healthcare Enterprise. Available at: www.rsna.org. Accessed August 10, 2003.
  2. The key to integrated systems/IHE integration profiles. Available at: www.rsna.org.