BM van Poppel
Hiscom
Leiden, The Netherlands
One of the prerequisites for the success of PACS, identified already in early PACS research, is the integration of PACS and RIS/HIS. As a major RIS/HIS supplier in the Netherlands we have standardized our interface with several PACS vendors on HL7. First we will describe the functional demands, secondly we will discuss some design choices. Next the various HL7 messages will be listed. Finally the conclusion.
The following functionalities should be covered:
1. Correct identification of patients and examinations/procedures on PACS
2. Consistency of duplicated data
3. Providing necessary data on the proper moments to support prefetching, a prerequisite for fast image retrieval
4. Presentation of current and historical data of studies/procedures coherently together with PACS images on PACS workstations
5. Presentation of PACS images (probably compressed) coherently with the alphanumeric report within the Electronic Patient Dossier (EPD) to clinicians in the hospital
In this section we discuss three important design choices. Firstly, we decided that PACS should appear as one single system. This is achieved by using an interface server within the (Dicom) PACS network that communicates with the world outside PACS. Secondly, it was decided that the RIS is the leading system for alphanumeric data among others examination/procedure data (the worklist) and alphanumeric reports. Thirdly, we had to accomodate the conceptual differences in the models used by RIS and PACS. In the Netherlands an order for an examination, mostly accompanied with a medical issue, may consist of several procedures, e.g. a CT and a chest. All films of all procedures are stored in an examination folder. The report refers to all procedures done. PACS systems on the other hand create separate electronic folders for each procedure. Procedure identification is done by either a barcode or by chosing from a worklist. From this discussion it follows that the messages between RIS and PACS should be on the procedure level rather than on the examination level.
The interface consists of the following HL7 messages:
·
HL7
order messages from RIS to PACS.
Whenever a new order for an examination/procedure is created (c.q. changed
resp. deleted) in the RIS the RIS sends for each procedure an order message
to the PACS. These orders for procedures are used to create the procedure
folder structure and to identify the procedures to be done for a patient.
Besides, these order messages support the needs of current PACS prefetching
algorithms.
·
HL7
ADT messages from the ADT system to the PACS.
To keep patient data in PACS consistent, changed patientattributes and linked
patientnumbers are sent to PACS by regular unsolicited HL7 ADT messages.
·
Query
for reports from PACS to RIS.
For presentation of alphanumeric reports on PACS workstations the reports
are retrieved from the RIS. The HL7 query mechanism for radiology reports
is used.
·
HL7
report messages from PACS to RIS
We propose to transfer the reference to the procedure folder to the RIS using
HL7 report messages. Outside the PACS -RIS/HIS interface the RIS sends the
reports, both text and image references, to the EPD.
Only after extensive discussions with our partners the functional demands for PACS-RIS/HIS integration could be identified and the design issues could be addressed. With all PACS vendors, currently five, the same HL7 interface will be used. The first preliminary implementation has been succesful and we plan to install this interface the coming year in over a dozen radiology departments.
Although a standard interface will diminish the efforts for realization and installation, to our expectation the integration of RIS and PACS within working procedures of users still asks for thorough project management.
Keywords: Integration, HL7, RIS, PACS, HIS
Corresponding Author:
Bas M. van Poppel
Hiscom
PO Box 901
2300 AX Leiden
The Netherlands
bvpoppel (at) hiscom (dot) nl
Oral presentation at EuroPACS'98, Barcelona, Spain