An Overview of the Integration of the UCSF Dept. of Radiology Teaching File with MIRC Wyatt M. Tellis University of California San Francisco Departments of Radiology and Biological and Medical Informatics

2 Introduction MIRC is a virtual community of medical image libraries that can be indexed and searched Libraries can be: –Teaching files –Research and reference image repositories –Clinical trial images and related data –Textbooks or papers –PowerPoint © and other types of presentations This presentation describes the process of integrating an existing database driven teaching file with MIRC

3 UCSF Teaching File Overview Web accessible Database driven –4th Dimension © RDBMS Integrated with PACS –Images entered from the PACS display station –Images automatically converted from DICOM to JPEG –Reports automatically retrieved from RIS In use since 1998 with over 14,300 cases –Used by all sections (neuroradiology, chest, abdominal imaging, skeletal, nuclear medicine, etc.)

Input Screen on PACS Display Demographics & history filled in automatically ACR codes used for indexing Additional content can be entered Select key images using PACS summary series tool

5 Search Page for Internal Use

UCSF Teaching File Display

Internet Server Index Server Index UCSF Query Service MedPix Server Index RSNA User UCSF uses its internal database to index its dynamically generated documents. UCSF TF Within MIRC

User Independent MIRC Storage Services User Submits Search Broadcast Query of All Storage Services User Views Content Hosted by Storage Services Query Service Receives Matching Results Query/Storage Service Interactions

9 MIRC Storage Service Integration UCSF TF acts as MIRC storage service –Integration achieved through MIRC query interface MIRC query interface responsibilities: –Receive MIRCquery document via HTTP POST –Extract query parameters from MIRCquery document –Perform actual query –Generate MIRCqueryresult document containing matching cases –Send MIRCqueryresult document back to query service

MIRC XML Document Schemas MIRCquery Document MIRCqueryresult Document

11 Storage Service Model * DB Query Service Storage Service User Web Server Control Logic Request Handlers XML Parser * Courtesy of Steve Moore

12 Storage Service Components Web Server –4D contains built-in web server –Handles network traffic between browser (and query service) and teaching file server Parses incoming HTTP requests Sends HTTP response data Database –4D contains built-in relational database –Used to store all text data Images stored externally with pointers in database

13 Storage Service Components Control Logic –Written in 4Ds scripting language Pascal-like syntax Uses third party plug-ins to extend scripting languages capabilities –Responsible for authenticating users –Delegates individual HTTP requests to appropriate handlers

14 Storage Service Components XML Parser –Expat4D plug-in provides XML support 4D does not inherently support XML parsing Freely available: Based on the open source, event driven, XML parser Expat –Used to parse MIRCquery document

15 Storage Service Components Request Handlers –Individual functions written in 4Ds scripting language –Approximately 70 handlers, each dedicated to processing a specific request: Perform query Send list of matching cases Send images –Handlers can make direct calls to underlying database to process a request

16 Storage Service Components Request Handlers (contd) –Apply access restrictions –Each handler generates the output that is sent as part of the HTTP response: HTML Binary data –JPEG –PDF XML (for MIRC) –New handler (query interface) added to process requests from MIRC query service

17 Query Interface Overview Single request handler –Receives MIRCquery document as input Uses Expat4D to parse XML –Performs query of database using parameters specified in MIRCquery document Translate MIRCs Boolean query syntax into database engines internal query language Map MIRCquery document elements to columns within the databases schema –Generates MIRCqueryresult document which is sent back to query service

Key Integration Issues Translating MIRCs query syntax into database engines internal query language –Supports Boolean operators: and and or –Uses quotes to define phrases –Uses parenthesis to create complex Boolean searches –Sample query: (alpha | bravo charlie) delta –Reused code from internal search page to process MIRC queries Query syntax is similar to the one already being used to search teaching file

19 Key Integration Issues Mapping of MIRC XML document elements to database schema –28 elements in MIRCquery document –MIRC spec allows you to ignore those that cant be mapped Anonymization of cases –Patient identifiers extensively used by radiologists –Flags added to specify whether case has been fully anonymized and can be shared with MIRC

20 Conclusion & Future Directions Use of well established standards makes integration with MIRC straightforward –HTTP –XML MIRC schema extensive enough to accommodate our teaching file schema –Schema continues to evolve to meet the communitys demands

21 Conclusion & Future Directions Initially required only three days of development time with subsequent refinements over the next couple of years –Schema changes –Addition of anonymization support Use of the MIRCdocument to integrate teaching file with authoring software developed at UCSF for creating eCME courses