Why have simple if you can have complicated instead? This seems to be the motto when transferring medical data in digital format. Why else would one of the simplest and most practical solutions so rarely be implemented in practice? We're talking about the IHE-XDM profile which defines everything you need for secure point-to-point communication in the widest variety of transmission paths – without any complicated IT architectures or technical resources.
Dr. Merzweiler, firstly, what exactly is the IHE-XDM profile and which processes was it developed for?
IHE-XDM is, in principle, a further development of the Portable Data for Imaging (PDI) profile which for many years has enabled DICOM data to be exchanged in a standardized way via a data carrier such as CD or USB stick. We wanted to take advantage of this uncomplicated transmission path for other medical data too. The IHE-XDM profile emerged in 2008 as a result of these efforts. One key feature of the profile is that data transmission takes place using simple, already available resources – in the simplest scenario, the transport vehicle is the patient who takes the data carrier from A to B. Unlike the earlier PDI profile, transmission via e-mail is also specified with XDM.
How exactly do the two profiles, XDM and XDS, differ?
IHE-XDS defines opportunities to build entire information networks across organizations, with a focus on aggregating patient treatment data. Communication is not generally aimed at a specific recipient, but instead at building an electronic patient record. The profile is a complex construct that usually requires building a standardized master patient index and using standardized metadata. It is therefore not suitable for normal communication between, for example, a general and a specialist physician and/or the patient. By contrast, the XDM profile requires no separate structure and far fewer organizational resources. In this way, the sender, for example, uses their usual metadata which the recipient must potentially adjust manually. Even this effort can generally be reduced by using IHE metadata, for example.
Can you combine the two profiles?
Yes, absolutely. The metadata needed for an XDS registry, and therefore the card index file for data management, are also potentially transmitted via XDM. This means that XDM is very well suited for letting medical data flow into an XDS infrastructure. In this way, communication between large healthcare facilities and their practitioners, for example, is simple and efficient.
Which specific scenarios is the XDM profile particularly well-suited for?
XDM is suited for any situation involving targeted communication, whether between specialist physicians, between the physician and the patient, or even between a hospital and a health insurance company's medical services. The simple type of transmission by data carrier or e-mail is extremely helpful in many everyday scenarios and is a by far better alternative than building individual, proprietary solutions. XDM can even be used as an archive, for example as an interim archive when switching systems. You are only limited by your imagination.
Imagination has no limits, but surely the profile itself has?
XDM does have its limits when it comes to managing patient IDs. Since there is no automation here, IDs must be transmitted by hand. In addition, we currently still have a limitation with DICOM data. At present, XDM is still not specific enough in its description of how DICOM and non-DICOM data is deposited on a common data carrier and is able to be subsequently read with the necessary level of interoperability. To overcome this limitation two change proposals were submitted to IHE International. These have already been included in the standard PDI and XDM texts. Even this hurdle has thus been overcome.
IHE-XDM Profile: Simply Too Practical?
Dr. Angela Merzweiler
is a founding standards expert. She now works freelance in training, consultancy and software development, specializing in DICOM and IHE.
IHE is already delivering many solution corridors for dealing with data in the medical world. As XDM's expansion story shows, often very little is still missing to enable existing profiles to address further application scenarios. A small addition to the PDI and XDM profile standard text has resulted in new challenges arising out of the GDPR requirements, for example, being able to be solved by the sector – and at a relatively small cost. Both PDI and XDM are now active globally in the standardized transportation of patient data in use (patient CDs). This also radiates from the status of the technology. So far, image data has been transmitted separately from other documents. But by grouping both profiles, entire patient records with any content can now also be exchanged very easily or handed over to the patient in a 'machine-readable and interoperable format' (Recital 68, GDPR) – in line with the technology status. Moreover, this approach is even pragmatic. It does not require any complicated infrastructure. Data can simply be transferred via a mobile data carrier, like a CD or a DVD, or even electronically as an encrypted e-mail. This once more demonstrates that it is worth working with IHE, because the standards also help to meet today's challenges.
Dr. Marc Kämmerer
Head of Innovation Management at VISUS