Image transmission and data compression. Two key elements of an electronic imaging department.

Growing numbers of diagnostic images are being produced electronically and filmed only for storage, or sometimes also for interpretation. However, in most imaging centers, transmission of images from one location to another is still being accomplished manually. Almost 40 years ago, x-rays were first transmitted over telephone lines, and this form of "teleradiology" has been increasingly used to link isolated hospitals and clinics to larger facilities so that radiologists can interpret the images. Continuing improvement of the various electronic image-processing technologies has produced faster means of transmission, and increasingly sophisticated computer algorithms for "compressing" the image data have further improved both transmission speed and the quality of the transmitted images. To date, only a few imaging research centers and teaching hospitals have integrated these techniques into a comprehensive picture archiving and communications system (PACS) or digital image management system (DIMS), and a number of factors are restraining these systems' spread. However, electronic transmission of images for interpretation by specialists at a central facility is likely to increase, and truly "filmless" radiology may someday become a reality, if image transmission and data compression techniques are eventually determined to create images of acceptable quality in all imaging modalities.