The path to the all-digital healthcare enterprise is strewn with integration hurdles that continue to challenge organizations striving to implement images and information across departments, from admission and registration to treatment and discharge. Incompatibilities between competing vendor's systems have forced hospitals to employ numerous software interfaces - including XML, service-oriented architecture and web services - to allow caregivers across the facility to access, review and update patient data.
For the past several years, the radiology information system (RIS) has been able to exchange patient data with the hospital information system (HIS). This includes admission, discharge and transfer (ADT) orders and other patient information stored in HL7 format in the HIS. More recently, healthcare organizations have been combining DICOM-format images and modality work lists stored in a picture archiving and communication system (PACS) with HL7 data in the RIS and HIS. This has been made possible by development of application programming interfaces (APIs), brokers, or intermediary data repositories where the HL7 to DICOM translation happens. Another method is a brokerless PACS, which can translate HL7 data to DICOM format and vice versa, allowing information to be seamlessly transferred from a HIS without additional software or hardware.
Cross-vendor compatibility initiatives such as Integrating the Healthcare Enterprise (IHE) address the problem of sharing different data types among disparate systems, but it's still no easy task to smooth the flow of patient data throughout the hospital. One clear benefit of the development of a standards framework like IHE is that it allows hospitals to implement products, including the HIS, RIS and PACS, from multiple vendors. Healthcare organizations of all sizes benefit from cross-vendor compatibility, but especially those with sprawling IT infrastructures, where IT and clinical departmental managers prefer to mix-and-match systems.
"There is no single vendor that has a system that will satisfy everyone," says Nogah Haramati, MD, chief of radiology at Montefiore Medical Center in New York, N.Y, and professor of clinical radiology and surgery at the Albert Einstein College of Medicine. The 1,062-bed organization has a LastWord HIS and Imagecast RIS from IDX Systems Corp. The RIS is connected to GE Healthcare's Centricity PACS. According to Haramati, IHE has taken the burden of developing software interfaces off of users and vendors.
"PACS and RIS vendors used to have to do secret, intensive work to create custom interfaces between systems," he says. "IHE is designed to solve the interface problems using existing standards, and rigidly specifying every transaction. The fundamental change is that IHE doesn't care how you define the system. Each vendor, whether it's the 800-pound gorilla or a start-up in a garage, can build its side of the technology. In every area, IHE will decide the critical discrete functions for image archiving, image display, or system rescheduling," he says.
"We learned that one size doesn't necessarily fit all," says Paul Chang, MD, director of radiology informatics at the University of Pittsburgh Medical Center in Pittsburgh, Pa. Chang, also professor of diagnostic radiology at the University of Pittsburgh School of Medicine and medical director of the Enterprise Middleware Group, is responsible for ensuring that all departments can share data across disparate systems across 19 hospitals with a combined 4,000 beds.
"Users should not have to compromise on product selection," Chang says. "Not just radiology, but all departments. I'm giving up too much if I give up best-of-breed."
Of course, when an organization implements PACS in addition to a RIS and other departmental systems, HL7 and DICOM data needs to be translated and shared by the two systems. But across the enterprise as a whole, those data formats are only a small part.
"Here, HL7 and DICOM are edge protocols, and simply asking specifically about integrating the HIS, RIS and PACS is asking the wrong question. That's more of a narrow, radiology perspective," says Chang, whose enterprise middleware group has developed a service-oriented architecture that uses Extensible Markup Language (XML) objects to exchange data between a Cerner Corp. HIS, Stentor Inc.'s iSite PACS (which Chang helped develop), and other web service-enabled systems.
Whatever the integration method - from brokers to custom APIs to XML - bi-directional communication between the HIS and RIS has become commonplace. Successful data integration requires first a thorough understanding of patient workflow through the organization, according to Stuart Gardner, president of Arlington, Texas-based SG&A Consulting Inc.
"To have a fully integrated environment, you have to understand the flow of text and image data. Using a Modality Performed Procedure Step, IHE specifies how information that comes from the ADT database is being added to the RIS and PACS, and how the new information goes back. The ADT database can also query the PACS database to update information," says Gardner.
Although hospitals have been sharing HL7 data between the HIS and RIS for years, adding PACS workstations and imaging modalities into the mix, with their DICOM-format data, is where the difficulty lies. At Massachusetts General Hospital in Boston, Mass., PACS brokers from Mitra Corp. (which is part of Agfa) allow the in-house HIS, IDX RIS and Agfa PACS to exchange HL7 and DICOM data. But the broker hasn't solved data consistency issues, says James Thrall, MD, radiologist in chief at the hospital.
"When you look at radiology, you have to ask what are all the things that live in HL7 format?" Thrall says. "The RIS, HIS, billing, and the longitudinal electronic medical record are all HL7. The challenge is to look at the DICOM world - the PACS, workstations, and modalities - which, in essence, HL7 does not talk to. Companies like Mitra came out with their brokers, but the process of allowing DICOM to talk to HL7 is still kludgy and fraught with difficulty," he says.
He explains that the IHE initiative will ease the process, but not until a large number of vendors include the compatibility profiles in their products. As it stands, a lot of data translation has to take place at the interface.
"We're not really seeing IHE in products yet," Thrall says. "Take [for example] patient demographic and scheduling information, which you have to send from within in the RIS to a scanner. But there are an infinite number of scanners available. You need to either build a custom interface or, in our own environment, use the Mitra PACS broker to populate the work list on the imaging device, 'backwards' to the PACS."
Single-vendor integration solutions
Several RIS vendors, including Misys Healthcare and Medical Information Technology Inc. (MediTech) offer integration software that does the work of translating and synchronizing information between the HIS, RIS and PACS. Misys does this with its PACS Integration Module (PIM), a brokerless integration engine that translates HL7 data to DICOM data to allow the RIS and PACS to share data. MediTech also offers software interfaces that handle the translation between the RIS and PACS.
For the past three years, Casa Grande Regional Medical Center, a 201-bed hospital in Casa Grande, Ariz., has used a RIS and PACS from Misys, with the company's PIM. Both systems can retrieve ADT records and other patient information from an HL7 database on an IBM AS/400. The goal at the hospital was to be able to share, update and reconcile patient data between the systems, says Frank Mollica, director of medical imaging.
"When a patient is registered in the HIS, that information comes across the PIM to the RIS, which is connected to the modality. We implemented the interface engine so work orders can be generated on the HIS, and come across and populate the RIS. Then, changes and test results can go back through the HIS to be archived. The work list information is at the modality level, stored in DICOM format, and HL7 information from the HIS is reconciled in the PIM," says Mollica.
Such automatic reconciliation of patient data eliminates a task that previously required close monitoring by IT personnel, who had to manually merge ADT data with image studies. "With the PIM, there are little to zero cases where the patient data can't be associated with a PACS image," says Mollica.
At Casa Grande, most of the 20 modality types connected to the PACS can receive DICOM work lists. At the two modalities that cannot, an attendant must manually enter work list information. If it doesn't match patient information coming from the HIS, the PIM will "flag" the error. As a result, productivity increases, says Mollica.
"The broker we used before the PIM required 15 additional workstations, terminals, or PCs that need to be set up for technologists to monitor them. We cut out the additional stations, where manual reconciliation took place," he says.
Other hospitals have seen similar benefits from integrating RIS and HIS data. Howard Regional Health System, a 54-bed facility in Kokomo, Ind., outsourced the task to MediTech. In January 2003, the hospital implemented the company's MAGIC HIS and Client/Server Release RIS. By implementing a single-vendor solution to systems integration, the healthcare facility ensured data consistency across departmental systems, says Emily Blomenberg, director of imaging.
"Prior to the MediTech system, we had a lot of data service issues with our standalone billing system. We quickly realized we had to make it one single system across the hospital so there are fewer interfaces to support," says Blomenberg.
When the hospital adds MediTech's PACS this year, the imaging department will be able to work with patient ADT records, which are stored in the MAGIC HIS in HL7 format. The MediTech interface will translate the ADT data to DICOM format for the PACS, which will in turn send it to any connected modality as a work list. Even prior to installing the PACS, the integration if HIS and RIS data has produced faster turnaround time from patient registration to exam at the modality, and it's accurate, without having to be constantly validated, says Blomenberg.
Turning to services
By creating web services, XML-based APIs and software "wrappers" that allow disparate systems such as the HIS and PACS to interoperate, organizations have a common underlying service-oriented software architecture. But healthcare facilities have been slow to implement web services, even though industries such as financial services, manufacturing and retail have begun to embrace the technology as the solution to interoperability.
"Outside the medical industry, everyone has the same problem, which is sharing data between systems," says the University of Pittsburgh's Chang. "When you step back, you see that this is not a unique problem. Workflow is getting increasingly complex, and systems that don't normally talk to each other have to talk to each other. Database synchronization is a symptom of that goal. But we don't need one big monolithic integrated HIS, RIS and PACS solution, we need to embrace XML, service-oriented architecture, and web services. Systems that use HL7 and DICOM can be consumed as web services by middleware. That's not the future, it's already moving."
The use of web services by many industries outside of healthcare has not gone unnoticed by professional organizations such as the Healthcare Information Management Systems Society (HIMSS) and Radiological Society of North America (RSNA), both of which expect to include XML in the IHE framework for interoperability between systems.
"When IHE tackles new areas, we'll look at standards, including XML document sharing and web services," says Joyce Sensmeier, director of professional services at HIMSS in Chicago. "That's the beauty of it: the technology framework says how HL7 and DICOM are applied, and that can include XML."
Specifically, XML will be addressed by the IHE IT infrastructure (ITI) effort related to Cross-enterprise Document Sharing, sometimes called XDS. Next year's ITI technical framework will likely include XML and web services, says Sensmeier.
Regardless of the method a healthcare facility chooses to integrate HIS and RIS data - a single-vendor solution or development of large-scale, XML-based custom interfaces - the goal is universal: to establish an electronic health record that contains data from the HIS, RIS and PACS, as well as other departmental systems across the healthcare enterprise.