Remote access to a web-based image distribution system

Purpose: To assess different network and security technologies for remote access to a web-based image distribution system of a hospital intranet. Materials and Methods: Following preparatory testing, the time-to-display (TTD) was measured for three image types (CR, CT, MR). The evaluation included two remote access technologies consisting of direct ISDN-Dial-Up or VPN connection (Virtual Private Network), with three different connection speeds of 64, 128 (ISDN) and 768 Kbit/s (ADSL-Asymmetric Digital Subscriber Line), as well as with lossless and lossy compression. Results: Depending on the image type, the TTD with lossless compression for 64 Kbit/s varied from 1:00 to 2:40 minutes, for 128 Kbit/s from 0:35 to 1:15 minutes and for ADSL from 0:15 to 0:45 minutes. The ISDN-Dial-Up connection was superior to VPN technology at 64 Kbit/s but did not allow higher connection speeds. Lossy compression reduced the TTD by half for all measurements. Conclusions: VPN technology is preferable to direct Dial-Up connections since it offers higher connection speeds and advantages in usage and security. For occasional usage, 128 Kbit/s (ISDN) can be considered sufficient, especially in conjunction with lossy compression. ADSL should be chosen when a more frequent usage is anticipated, whereby lossy compression may be omitted. Due to higher bandwidths and improved usability, the web-based approach appears superior to conventional teleradiology systems.