The PACS Workstation: A Theory of Evolution

David Weiss, MD


Appl Radiol. 2008;37(8):24-29. 

In This Article

Today's Requirements, Tomorrow's Technology

The current PACS workstation is functional and utilitarian, a combination acceptable to many practicing radiologists. Images are displayed in a reasonable length of time with personalized hanging protocols. Image manipulation and annotation can be performed in a marginally acceptable number of steps. Worklist functionality is arguably robust enough for the average user. But there is great potential to take the average PACS workstation to a much higher level of functionality with some relatively minor modifications.

Current worklist functionality in many PACS accommodates only 2 states–read and unread–with studies dropping from the worklist as soon as they are marked read. This, however, is a simplistic view of quotidian workflow in the average radiology department. Many cases are not ready to be read, yet should not remain on the worklist. A study that needs a second opinion or one that needs additional views should be moved temporarily to a separate folder until these requirements are met. Likewise, there should be easy functionality to copy a study to another folder, such as an interesting case list or a teaching file. The folder concept was introduced early in PACS development[4]and is now being expanded by most vendors to further improve usability and functionality.

With the exponential increase in corporate acquisitions and the consolidation of hospitals and imaging centers, many radiologists are facing the daunting task of using multiple PACS and radiology information systems in their daily image interpretation, moving from workstation to workstation and interacting with multiple user interfaces. A single worklist orchestrator is now within reach to consolidate all workflow to a centralized worklist. Ultimately, all of these images could be consolidated as well in DICOM format and interpreted on a single viewer, obviating the need for a knowledge of multiple user interfaces.

Hanging protocols, the ability to automatically arrange and display images in the proper configuration and sequence,[4]must improve as well. As the number and diversity of image series become more pervasive, vendors are facing the challenge of increasing the complexity of hanging protocols while at the same time maintaining ease of creation by the user. A good example of this is digital mammography, in which many users are finding that the switch to softcopy reading is accompanied by a decrease in the speed of interpretation.[5]The development of reading protocols–an automated user-defined sequence of hanging protocols–has helped but has not alleviated this negative impact. Future hanging protocols must accommodate not only conventional images but also advanced visualization techniques. In fact, some radiologists are abandoning conventional PACS to view images primarily on their advanced visualization workstations. PACS vendors are taking steps to reverse this trend by offering native advanced visualization features. They must also begin to incorporate third-party volume image interpretation into their own hanging protocols.

The graphic user interface (GUI), the feature used to manipulate and annotate images, needs some streamlining in almost every current PACS. Most workstation software now relies on some combination of pulldown menu, icon click, or keyboard commands for user input. Studies have shown that any time a radiologist's eyes move from the image it creates a distraction, which has the potential for decreased diagnostic accuracy.[6]The future GUI must allow total image manipulation without visual input. This can be accomplished to a great extent with alternate mechanical user interface devices (such as the ShuttlePro, Contour Design, Inc., Windham, NH) combined with software modifications (Figure 1). An increasing number of radiologists are finding this workflow useful in daily image interpretation.[7]

Communication features are an integral part of PACS and should be easily accessible at the workstation. These include not only the creation of a conventional radiology report, but also real-time bidirectional collaboration among radiologists and clinicians. With more and more reports being sent and read using electronic means, the multimedia report is becoming more popular. Such a report can include annotated thumbnail images with hyperlinks to appropriate text, voice recordings, links to online references, and other advanced features that create a richer environment for information exchange between the radiologist and the clinician.[8] The PACS workstation must accommodate these new features and allow efficient creation of these reports by the radiologist. This will be possible only by maximizing interoperability between the reporting and the image viewing software. Radiologists also have an increasing need for rapid and contextual data retrieval from the electronic medical record. It is no longer sufficient to simply have access to all of the laboratory values for a particular patient. The software should have the functional intelligence to filter this data depending on the situation. For example, if a radiologist is working in the protocol page for a CT scan, the system should have the ability to display the latest renal function studies automatically.

Until recently, PACS vendors' focus has been on consolidating the features discussed above and improving usability and efficiency at the workstation level. Like building a home, these are structural and required features, such as roofing and siding. Network capability, like wiring and plumbing, is also an absolute requirement that should function in the background without visibility. Such is the current status of PACS workstation functionality. We have built our homes with relatively robust infrastructure and are secure from the elements. We must now look toward improving our surroundings by accessorizing this environment with third-party functionality. PACS vendors have always faced the dilemma of which features to provide with native software versus utilization of third-party specialty vendors. Many radiologists prefer highly functional nuclear medicine, ultrasound, and advanced visualization software to those available on their own PACS workstations. Digital mammography is an extreme example in which, until recently, a stand-alone specialty workstation supplied by the mammography vendor was an absolute requirement for digital interpretation. These divisions are becoming blurred as vendors begin to include not only native specialty interpretation software within PACS but also increasingly seamless integration with third-party vendors. In addition, some vendors are partnering with third-party companies to allow users to create highly customized worklists based on their individual workflow. Third-party data search engines and decision-support software is also being integrated into PACS. These advances will benefit radiologists as we continue to squeeze out every drop of efficiency in an attempt to accommodate an ever-expanding number of images.


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