Consistency of Softcopy and Hardcopy: Preliminary Experiences with the new DICOM Extensions for Image Display

The DICOM standard defines in detail how medical images can be transmitted and stored. However, there have been no precise rules on how to interpret the parameters contained in a DICOM image which deal with the image presentation. As a result, the same image frequently looks different when displayed on different workstations or printed on a film from various printers. Three new DICOM extensions attempt to close this gap by defining a comprehensive model for the display of images on softcopy and hardcopy devices: Grayscale Standard Display Function, Grayscale Softcopy Presentation State and Presentation Look Up Table. A prototype implementation of these extensions has been shown at the 1999 annual tradeshow of the Radiological Society of North America (RSNA) as part of the scientific exhibit (infoRAD). This demonstrated a simulated radiological workflow in which images were created, interpreted at a diagnostic workstation and later reviewed on a clinical workstation. Images could also be printed using DICOM Print. The prototype shows a proof of concept, i. e. that image integrity and consistency over a variety of display and print devices can be achieved and in addition, that the new DICOM extensions can be implemented relatively easily, without a significant performance penalty. The extensions allow to store all parameters defining how an image is displayed or printed in a separate DICOM object that can be managed with the existing DICOM database services. In particular, this satisfies the users’ need to view images at different locations in a consistent manner, and to document the image appearance on which a diagnosis is made in softcopy environments.