CODEWITHSUNDEEP
hl7hl7-v2
Tarmo R
Tarmo R

Reputation: 1153

Modality for radiology orders in ORM^O01 message

Our DICOM Modality Worklist server is currently receiving HL7 ORM^O01 orders from our hospital RIS. To map each order to a modality we are currently using the OBR-24 field in the message. The codes contained in OBR-24 are mapped to AE titles and modality by a lookup table in the MWL server. The current OBR-24 values are something along the lines of "LOC_STATION", where LOC is the location (on building level) for the scheduled station and STATION is the scheduled station for the current order.

Now a need has arisen to direct the same incoming message feed to another system for prefetching prior studies from a slower long-time archive based on the orders. An important input parameter for the prefetch engine rules is the modality of the ordered study. Therefore we would like to add the DICOM modality code in the incoming order messages, since we do not want to duplicate the entire lookup tables system and manage it separately in two places.

What would the best field for this kind information be inside the ORM^O01 structure as defined in v2.3.1 of HL7 standard? I have skimmed the standard and went through our MWL server vendor reference materials, but the closest I have found, is the same OBR-24 field, which is already in use in our solution. Or should we look at implementing some kind of custom Z-segment?

The situation is additionally complicated by the fact, that we are an independent PACS service provider, therefore we do not control the development of the HIS/RIS softwares in the hospitals and mostly we have to integrate with existing systems with minimum modifications on their side. Therefore it is quite difficult to change or move any of the existing fields in our messaging standard, but it's easier to implement new unused fields for new purposes.

Upvotes: 1

Views: 6473

Answers (1)

xmojmr
xmojmr

Reputation: 8145

IHE Radiology Technical Framework - Volume 2 (RAD TF-2): Transactions, Appendix B: HL7 Order Mapping to DICOM MWL also does not specify recommended mapping for DICOM tags

  • (0040,0001) Scheduled Station AE Title
  • (0008,0060) Modality.

In our ORM^O01 generator we use placer fields and filler fields (HL7 items #00251, #00252, #00253, #00254 - OBR-18..OBR-21) for the application entity title and the diagnostic service section id (HL7 item #00257 - OBR-24) for the modality code.

You can place your current routing information into the receiving facility field (MSH-6) and thus release the OBR-24 for another use.

MSH-6 (Receiving Facility, item #00006) was originally meant to represent part of the "receiver's address", the "LOC_STATION". While the MSH-5 indicates your PACS service address, the MSH-6 might be used to designate where next should the order go. This way you would not need to put the same information again into OBR-24 and you can use OBR-24 for just the modality code.

It should be ok to place it nearly anywhere as long as you document it in your conformance statement so that admins of the interface engines can define corresponding mapping.

If you can not change/influence the incoming message format then you may find useful some kind of universal field remapping service before the incoming message are processed or passed on to DICOM clients.

For an example of what I mean look at the XSLT mapping script used by the dcm4che.org open source DICOM Clinical Data Manager system with HL7/PACS/DICOM interfaces built-in. When a HL7 v2 message arrives, it is translated into its equivalent XML representation, transformed by a vendor-specific XSLT script and then pushed into a DICOM database storage. One of the default ORM^O01 mappings is in folder https://svn.code.sf.net/p/dcm4che/svn/dcm4chee/dcm4chee-arc/trunk/dcm4jboss-hl7/src/etc/conf/dcm4chee-hl7 in file orm2dcm.xsl

Upvotes: 3

Related Questions