DICOM UPDATE: Soft-copy presentation supplement debuts at ECR

April 1, 1999

Soft-copy presentation supplement debuts at ECROne problem PACS users often report is the difficulty in maintaining consistent presentation of images when viewing them on different workstations. A new DICOM supplement demonstrated at last month's

Soft-copy presentation supplement debuts at ECR

One problem PACS users often report is the difficulty in maintaining consistent presentation of images when viewing them on different workstations. A new DICOM supplement demonstrated at last month's European Congress of Radiology in Vienna shows promise in solving this problem.

In a demonstration sponsored by the DICOM Committee, images were generated by a modality simulator and exchanged between a high-resolution diagnostic workstation and a PC-based physician viewing station. A consistent image presentation was maintained on the screens.

Consistency was secured via the generation of a new DICOM object, called the soft-copy presentation state, which develops an audit trail of all image manipulation functions employed by the user. The user can then store this "state" and send it along with the images for a consistent image presentation at another workstation. The information can be archived, and can refer to one image or to multiple images in a complete series.

This new DICOM service will impact end users in many ways. In some instances, CR images are acquired by exposing an imaging plate sideways. This is frequently done for a person whose chest does not fit on a standard 14-inch film width, but whose shoulders occupy the 17-inch length of the film and/or imaging plate. The image would appear at the viewing station rotated 90†.

Another situation that could benefit from the new state is a CT series of the abdomen that requires a zoom to be applied to all images in order to see the spine clearly. A technologist could apply the required rotate, shutter, or zoom factors at the modality or QA workstation. The image would be sent to the radiologist and come up on the workstation correctly, without the need to perform any of these manipulations. This closely replicates a traditional film-based environment, where a technologist or film technician makes sure the films are positioned correctly on the alternator for the radiologist.

This new supplement was implemented as a prototype at the ECR by a consortium of universities and consultants under contract from the DICOM Committee. The objective was two-fold: to test the DICOM specification to ensure that it is truly implementable; and to promote this new supplement, create awareness of the image consistency problem, and solicit feedback. A cyber-theater at the meeting allowed participants to create, store, and recall the presentation states using the available computers.

The software will be available in the public domain at http://www.microtherapy.de/go/dicomscope or http://www.offis.uni-oldenburg.de/projekte/dicom. It consists of a Java-based DICOM viewer and underlying software that implements this new DICOM service. The implementation is platform-independent, and can run in either a Windows or Sun Solaris environment. Based on its success at the ECR, it is almost certain that the demonstration will be repeated in an extended form during this year's RSNA meeting. The DICOM Committee's intention is to include the hard copy (film) in the demonstration as well, so that the images on the monitor can be compared with the printed film.

--By Herman Oosterwijk, president OTech Inc. at herman@otechimg.com