Industry reflection

The future life cycle of image data

By Claes Lundström, PhD, Director of Product Management & Research, Sectra Medical

The steadily increasing size of image stacks is generally agreed to be one of the most important issues of the future for radiology. The development is, of course, driven by the desire to improve diagnostics and the quality of care. The advantages of thin slices and advanced examinations are great in many situations, so it is clear that the significant increase in image production will continue.

This obviously entails efficiency prolems in the flow of radiological work, from both a technical and human perspective. In this article, a vision is presented of how images can flow and be stored in a future system that will enable new levels of efficiency in image diagnostics.

The first issue relates to the two main types of image-viewing systems found in radiology departments: modality workstations and PACS. What is the best way to divide responsibility between the two systems? Let us begin with a brief retrospective. What did a CT scan look like in a film-based workflow? The images were created and were accessible on the modality’s workstation. They were then printed on film, but this step entailed a reduction of information, a “summarization,” primarily because the images became limited to a single window view.

In today’s fully digital world, grayscale windows can be freely used, including during a review, which is a major advantage. However, the “summarizing” approach unfortunately lives on in another way, namely in terms of thin and thick slices. All images that are created, the thin slices, are accessible on the modality. But it is usually a summary, or reconstructed thick slices, that is then “printed” on PACS. There is a great potential for improvement in this area.

In principle, it is easy to question the fact that a great deal of energy is exerted in developing high-resolution images when perhaps 80 percent of the information is then discarded, before the majority of the review is carried out. If anything, it seems obvious that radiology should have all data accessible in its most important reviewing tool, the PACS workstation. Of course, it remains possible for the radiologist to trudge over to the modality workstation. But this work method works is counter productive to many of PACS’s advantages: the efficiency of having “all images, whenever, wherever” is lost, as is the opportunity to use the thin slices for future comparisons.

It is easy to see these flaws in the current work method, but of course it is not as easy to correct them. There is a major technical problem: quite simply, no PACS has been able to handle these enormous quantities of data and maintain its performance from a user perspective. That is why Sectra has invested so much time over several years in creating a new architecture. We are seeing the result now, in a unique system led by IDS7, in which speed for large datasets is making significant progress. But we must not forget the tools for those who must review these massive stacks. No matter how fast the system is, it takes too long to browse through thousands of slices for each examination. This is Sectra’s next major challenge, and both research and development are working to find innovative solutions.

The conclusion of the above reasoning is that radiology should put pressure on the PACS suppliers and demand “All images in PACS!” Having access to all the diagnostic image information produced guarantees a smooth work situation and high quality in reviews.

An example of this imbalance in the way modalities and PACS “divide the labor” is reconstructions. A typical routine is to work on a modality to use thin slices to create three different projections with thick slices and send them to PACS. PACS will then contain three versions of the same image volume, but with inferior quality. A more attractive option for the future is to reconstruct only in PACS. In this case, the thin slices are sent to PACS, where new projections can rapidly be reconstructed when necessary.

It is often suitable to do this with automatic hanging protocols (DDPs), so that no manual steps are involved. One advantage is thus that the step of reconstruction at the modality can be avoided. However, an even greater advantage is that one can synchronize reconstructions of old examinations, so that comparable images with full quality can be guaranteed. We have not yet seen a system that completely supports the principle of reconstruction in PACS, but Sectra is well on the way to offering that possibility.

The obvious follow-up question is long-term storage. When the images are new, it is desirable to have access to all of them, but the older they become, the more attractive it becomes to reduce the storage size. Many solutions are possible. At one end of the scale is “everything online,” in which the speed of accessing data is prioritized because, in terms of storage, no distinction is made between brand new and old pictures. The opposite entails that, immediately after the answer is written, the images are tightly com-pressed and perhaps reduced to thick slices, which mini-mizes the storage space but presents disadvantages in terms of access and quality in future use.

So which version is the ultimate one for Sectra to work toward? The answer: all of them at the same time! Flexibility will be the key word.

We are already seeing our customers around the world using very different reasoning. The prioritization between speed and completeness varies. Legislative requirements differ, but are also interpreted differently. Regional and national archives for complete storage are being developed in some places, while other customers would prefer never to save a single pixel that does not expressly form the basis of a diagnosis. Even within a single radiology department, a spectrum of solutions will certainly be in demand. For example, different types of examinations have different value as future references and should therefore be handled differently in terms of storage.

Cost-effective future PACS should thus have several scenarios for storage that define the ”life cycle” for image data based on milestones in the workflow. In addition, it should be possible for all scenarios to be active at the same time in a single system.

In conclusion, with all images in PACS and a streamlined storage solution, we will be a step closer to the perfect IT support for image diagnostics.

Author: Claes Lundström, PhD, Director of Product Management & Research, Sectra Medical

Related reading

Related products