Benefits multiply when digital teaching files added to PACS

November 25, 2002

A digital teaching file (DTF) doesn't have to be either expensive to own or difficult to maintain. Having long maintained a large film-based or analog teaching file in our division of neuroradiology/ENT, I consider the digital version the clear leader

A digital teaching file (DTF) doesn't have to be either expensive to own or difficult to maintain. Having long maintained a large film-based or analog teaching file in our division of neuroradiology/ENT, I consider the digital version the clear leader for performance and features, maintenance, expansion, and utilization. It is also better for direct and indirect costs.

Our neuroradiology/ENT DTF contains more than 7400 individual cases, including the manual entries from the analog file, and has been available for general use for about one and a half years. The feature most responsible for making the DTF successful is the link to our PACS for submission of new material. The DTF also offers several value-added features that are not inherent to the analog files: centralization of case material submissions, decentralization of teaching file access via the Web, permanence of case material, convenient access to old material, and easy submission of new material.

Several years ago, it became clear to us that our analog file was growing beyond our control in terms of film acquisition, storage space, cataloging, and security. While the imaging content was kept contained in a series of locked cabinets, our fellows meticulously maintained a teaching file catalog using a single user database on a PC. This required manual entry of all clinical demographics into the database, collection of pertinent films, and labeling and filing of film jackets and other materials such as references, pathology, and surgical summaries.

It was difficult to get users to use the collection responsibly and even more difficult to monitor them. The longevity of an individual case was inversely proportional to its use. The only repository that contained reliable data was the PC database that served as a catalog to the actual film teaching file.

Faced with these problems, we undertook a pilot project to migrate toward a digital solution for a neuroradiology teaching file with the following objectives:

?build a functional DTF Web server using off-the-shelf hardware/software
?build a custom interface to our PACS to allow submission of interesting cases directly from the PACS workstation
?make the submission process very simple
?permit open access to the DTF contents and "encourage" participation at all levels to contribute to the collection
?accomplish this with little added expense and minimal overhead

Our teaching file Web server is assembled on a basic networked desktop PC running Windows 2000 and FileMaker Pro. FileMaker offers a simple flat database solution as well as capabilities for building relational databases. The FileMaker program includes a ready-to-run Web server plug-in that, once activated, will automatically display data on a Web browser. FileMaker's proprietary version of dynamic hypertext markup language (DHTML, known as CDML) is used to build custom Web pages to display and query the database. A shareware FTP server is also installed on the desktop PC ( to receive and store image data as images are sent (via FTP protocol) to the server from the PACS.

The final piece of the project entailed development of a simple applet that would link any PACS workstation on our network to the DTF. This custom applet was written in the common open source scripting languages.

Our PACS vendor offers a simple solution to create JPEG versions of selected images while reviewing a study. The selected images are adjusted for window/level settings, cropped and panned by the radiologist, and stored on a temporary directory in the PACS workstation. With a button push, the scripting applet invokes a small window where a provisionary diagnosis is entered. When the window is closed, the applet "packages" the images by renaming them with a unique exam key number. It creates and labels a new directory on the Web server with this number and transfers the images to this directory. The images are "scrubbed" of all demographic data. The applet then constructs a common gateway interface command that is sent to the Web server (via standard http protocol) to instruct the database to create a new record with matching appropriate demographic and image information to link to the newly arrived image set.

The submission process, which requires about 15 to 60 seconds of the radiologist's time, is far more efficient than the steps involved to create a submission for the analog file. Moreover, while an analog submission process is largely retrospective - completed at the end of the day or week - the DTF submission is prospective and designed to occur during image review. We have had a much higher compliance rate with DTF submissions over analog submissions due to the convenience of performing the submission during readout and the ease of subsequent access.

On any given workday, the Web server may receive two to eight new teaching case submissions. The case and images are available for immediate review from anywhere in the medical center following submission. The entire collection is backed up nightly to a network hard drive.

Librarian functions for the DTF are minimal. Since the DTF is self-sustaining, it requires minimal upkeep and supervision. And since the DTF is Web-enabled, the library functions are accessible from any location where a networked PC is available. Periodic checks are made of the recent submissions to edit the demographics and to catalog the cases in broad disease and anatomic categories such as primary neoplastic or orbit. If necessary, captions can be added to each image or individual images can be removed from display.

The DTF is much more versatile than the analog file. With DHTML, once the case data are in the database, the method of delivery of the content is virtually unlimited. Use of dynamic Web pages instead of static pages ensures that the delivered content evolves as each DHTML template is improved.

Our DTF offers several options for viewing:

?browsing the entire database
?searching the database by disease, anatomic category, or specific diagnosis
?viewing the latest submissions
?viewing in a quiz format in which cases are presented randomly to the user as an unknown

In addition, there are links to cases with related diagnoses, links to the latest literature relevant to the diagnosis, and an unknown of the month contest in which residents can submit online answers. The prior unknowns are presented with the correct diagnosis and a discussion of the disease entity.

The latest submissions list is used as an aid for our weekly neuroradiology/ENT teaching case conference. Participants can use the PACS submission tool to bookmark cases for discussion at the regular conference. The DTF is also used to give unknown case reviews to residents preparing for the oral boards. Images can be copied directly from the Web browser to a PowerPoint presentation slide to augment an electronic presentation. Additional features under development include a neuropathology submission tool that will permit the neuropathologist to link relevant pathologic images and text to specific case material in the DTF from their laboratory.

The most important factor in making a successful transition from analog to DTF is the cultural change. A DTF is truly a success when it becomes a community project. Images are no longer collected for individual use but for the good of the entire collection. If you can achieve a high level of compliance, everyone benefits and there is no longer dependence on a single individual or group of individuals to maintain the content.

Dr. Flanders is a professor of radiology/ENT and rehabilitation medicine, codirector for the division of neuroradiology/ENT, and director of radiology informatics research at Thomas Jefferson University Hospital in Philadelphia.