Thursday, August 1, 2019

SIIM19 part 2: Standards update.


As the representatives for the various standards committees (DICOM, FHIR, IHE) reiterated during the recent 2019 SIIM conference in Denver, there are several new interoperability standards available that could make your life easier, but if the user community does not ask for them in their RFP’s and during regular vendor discussions, there is no incentive for these to be implemented.
Obviously, if you don’t know what to ask for, it gets difficult, therefore here is a synopsis of the new DICOM standards developments covered during the SIIM19 conference:


1.       Multi-energy CT imaging – CT scanners are getting equipped to acquire images using different X-ray energy spectra, which then are processed, subtracted, etc. to provide a different clinical perspective. When the initial CT DICOM metadata was defined in the early 1990’s, there were no multi-spectral CT scanners available or even thought of, therefore, to encode this with the “old” CT data requires a lot of customization and proprietary encoding, hence the need for a new series of objects. 

Remember that it does not only require the acquisition devices to support this new standard, which seems to be the least of the worry given the experience with adapting recent new DICOM objects, but more importantly, the PACS/VNA back-ends and especially the PACS and enterprise viewers will need to support it as well. There are 4 additional “families” of CT objects defined, i.e. for image encoding, material quantification, labeling and visualization.

2.       Contrast administration – Most US institutions have implemented an X-ray radiation dose recording and management system, motivated by the US federal requirements to put the dose information in each CT radiology report. The next area for potential legislative requirements and implementation is the contrast administration and corresponding management as contrast can also be detrimental to a person’s body.

The DICOM contrast agent administration reporting capability will facilitate this. The implementation is very similar to the dose reporting, i.e. it will be recorded in a dedicated Structured Report which provides details about the contrast which was programmed at the injector device and what is actually delivered.

3.       3-D printing – The RSNA hosted a big pavilion showing 3-D models and applications, initially for surgery planning, but eventually for implants. This is a new upcoming area, its management is currently shared between surgery and radiology. There is a need to retain and archive these 3-D “print files” and also for standard interfaces to the various 3-D printers. The DICOM standard added an encapsulation of these print files, called STL (an abbreviation of "stereolithography"). STL is file format native to the stereolithography CAD software created by 3D Systems and is also supported by many other software packages; it is widely used for rapid prototyping, 3D printing and computer-aided manufacturing. The 3-D model usage codes defined by DICOM include those used for:
a.       Educational purposes, such as training, patient education, etc.
b.       Tool fabrication for medical procedures such as radiation shields, drilling guides, etc.
c.       External prosthetics
d.       Whole or partial implants
e.       Surgery simulation
f.        Procedure planning
g.       Diagnostics
h.       Quality Control

4.       DICOMWeb – DICOMWeb provides a protocol alternative to the traditional DICOM protocol that is very effective in exchanging information using webservices and therefore is more suitable for mobile applications than the “traditional” DICOM protocol. There are equivalent services of the traditional DICOM Store, Move, and Find by using STOW, WADO and QIDO as well as the capability for bulk transfer (pixel data only) and metadata (header data) only. The webservices have been re-documented by cleaning up the existing documentation. In addition, a new enhancement has been defined to exchange thumbnails, so now instead of selecting the first image of a series as a source for the thumbnail, one can select an image that is representative of a series of images.

5.       Security – Cybersecurity is a big issue because of a recent publication about the possibility of using metadata that contains malicious data to store images on a CD. The Security Working Group together with the MITA cybersecurity people have issued a publication about this issue with precautions, (see press release). The metadata aka preamble could contain an executable; therefore, one is encouraged to use a virus scan and also disable running any executables from the media.

6.       Consistent protocols – for use by XA and MR are important in case a radiologist wants to compare a study with previous ones and also to compare studies that were created in different organizations. A DICOM extension allows for storing these protocols so they can be reused.

7.       Artificial Intelligence (AI) – is getting a lot of attention. Guidelines on how to include AI annotations and how to incorporate these into the workflow are defined. Assuming that the annotations are encoded in a DICOM Structured Report, there is a JSON representation of the DICOM SR defined.

8.       Dermatology – revitalized to address dermoscopy, which uses surface microscopy to evaluate skin lesions and can be used for early detection of skin cancer. It is an extension to the regular photography file definitions with new codes that are added.

9.       Ultrasound – has been revitalized to come up with a proposal to track transducers. This is somewhat of a challenge as not all of these probes are “intelligent” and can exchange a unique identifier. It is important to track transducers for infection control.

As mentioned earlier, if the user community does not request these new features, there is little chance that they will be implemented in a timely fashion by the manufacturers. A rule of thumb that I recommend is that one includes in the RFP an automatic upgrade for all new DICOM features within a reasonable time (e.g. 3 years) unless federal and/or state requirements require it to be sooner such as is the case for dose reporting (and might be for contrast administration).

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