As the global economy and global business practices increase, individuals tend to be more transient. Their medical histories are an important precursor to successful health care provisioning. Contingent upon this medical history record is the successful integration of data from varied sources, including the mobile patient’s information. This information must be portable, presentable, and independent of the initial data program from which it was obtained. By far, the greatest concern relates to data inconsistency and subsequent inaccuracy in an environment of disparate systems. In the next section of this article, we will discuss the Health Level Seven communication protocol. In the third section, we will discuss the protocol DICOM. The application of these protocols into solutions for healthcare information repositories is presented in the fourth section, where both PACS and RIS systems are discussed. The problem of Data Disparity that causes inconsistencies in the intersystem communications will be discussed in the fifth section. The design of the XML Bus solution will be presented in the sixth section. The successes and shortcomings of this design are discussed in the conclusion.
Key Terms in this Chapter
Digital Imaging and Communications in Medicine (DICOM): A standard for the distribution and viewing of medical images, such as CT scans, MRIs, and ultrasound. It describes a file format for the distribution of images and provides access to Storage Media independently from specific media storage formats and file structures.
Service Class Provider (SCP): In DICOM, the relationship between both partners is defined by the Service Class description. The SCP plays the “server” role to perform operations and invoke notifications during an Association. An example of a Storage Service Class Provider would be an image storage device. The SCP role includes enabling the applications to receive DICOM objects locally from devices (image sources, workstations, servers, and so on) through the DICOM protocol.
Clinical Context Object Workgroup (CCOW): More commonly known as Clinical Context Management, enables the clinical end-user to experience the simplicity of interacting with one system, when in reality he or she may be using multiple independent applications through varying interfaces. Defined by HL7 standards, CCOW ensures secure and consistent access to patient data from varied sources.
Clinical Document Architecture (CDA): Also known as the Patient Record Architecture (PRA), provides an exchange model for clinical documents (such as discharge summaries and progress notes). CDA brings the healthcare industry closer to the realization of an electronic medical record.
Modality Work List: The Modality Work List service provides patient demographic information to imaging modalities in the form of a work list. Modality work lists also allow technologists to sort their workload by time period, specific date or time, patient name or identifier, and modality.
Network Time Protocol/Simple Network Time Protocol (NTP/SNTP): NTP is an Internet protocol used to synchronize the clocks of computers to some time reference. SNTP (Simple Network Time Protocol) is basically also NTP, but lacks some internal algorithms that are not needed for all types of servers.
Comma Separated Values (CSV): This file format is often used to exchange data between differently similar applications. CSV files have become somewhat obsolete, due to XML data exchange possibilities.
Workflow Management System: A system that completely defines, manages, and executes “workflows” through the execution of software whose order of execution is driven by a computer representation of the workflow logic. The workflow is concerned with the automation of procedures where documents, information, or tasks are passed between participants according to a defined set of rules to achieve, or contribute to, an overall business goal (Hollingsworth, 1995).
Service Class User (SCU): In DICOM, the relationship between both partners is defined by the Service Class description. The SCU plays the “client” role to invoke operations and perform notifications during an Association. An example of a Storage Service Class User would be an image acquisition device. In this case, the image acquisition device will create and send a DICOM image by requesting that a Service Class Provider store that image.
Picture Archive and Communication System (PACS): A network of computers dedicated to the storage, retrieval, distribution, and presentation of images. A PACS system provides a single point of access for images and their associated data. It also interfaces with existing hospital information systems, such as the hospital information system (HIS) and the radiology information system (RIS).
Service Object-Pair (SOP): SOP classes identify the capabilities of the specific distributed processing for a certain Service Class. When partners agree to use a SOP class, both sides must ensure they will play their role as described, using the context of the enclosing Service Class. In each SOP Class definition, a single Information Object Definition or IOD is combined with one or more services.
Health Level Seven (HL7): A standard for exchanging information between medical applications. It is an event driven protocol that defines the format and the content of the messages that applications must use when exchanging data with each another in various circumstances.
Modality Performed Procedure Steps (MPPS): The MPPS service works in concert with the Modality Work List service to provide exam status updates. MPPS are used for two purposes: updates the exam state of patient and forward messages to another application entity, such as a RIS or other work list provider.