We have integrated several classes of intelligent software modules into our existing PACS. The first class can be categorized as general decision-making routines and include study routing, comparison image retrieval, study migration, storage management, and fault tolerance algorithms. These algorithms are rule based. The second class include user interface routines that allow radiologist to operate a PACS workstation within their own knowledge domain. Thus, window and level operations are translated into options to improve visualization of soft tissue or bone. The third class of intelligent modules are performance optimization algorithms and include optimizing file retrieval speed from a distributed PACS, optimizing T1-T2 contrast for various brain lesions in MR images, and automatic contrast and brightness adjustment of images displayed on PACS workstations. The effects of these intelligent algorithms on our PACS operation has been improved system reliability and study availability, and has made workstations easy to use. Currently, we are developing a general framework for the development of a knowledge-based multi-media distributed database management system for PACS which will support abstract and approximate query processing.