With the advent of digital photography, digital images are being used more often for the teaching of medicine. However, these images are "static", and do not recreate the experience of looking at a glass slide under the microscope. A virtual digital slide should recreate this experience, enabling the student to zoom in and out of an image, and move around (pan around) the slide. In order to create such a virtual slide, we took several overlapping photomicrographs with a digital camera, and "stitched" them together with a digital imaging stitching program (VirtualStitcher, Panavue, and Quebec, Canada). A composite jpeg image of approximately 8000 X 8000 pixels was made.

In the first version of this program, several smaller versions of this large image were made (lower magnifications). An Authorware (Macromedia, San Francisco, CA) program was written, in which, by a click of the mouse, one could go to a higher "magnification", and one could move around the slide by dragging the mouse. This program fulfilled all the requirements for a digital slide; however, at the highest magnification, the large jpeg image took a long time to load.

In the second version of the program, the large composite jpeg image was converted to a flashpix (*.fpx) image. The Active-X control was obtained from LivePicture (now MGISoft), and was used in an Authorware program to view flashpix image. With this Active-X control, the several sized images of the fpx image could be viewed, and one could drag across the image to move around the slide.

In a third iteration of the program, the large composite jpeg image was converted to an Apple QuickTime VR movie (VR Panoworx, VRToolbox, Pittsburgh, PA) and was viewed with the QuickTime viewer (Apple Computer, Cupertino, CA). In this version, the user is able to continuously zoom in or out, and can drag the mouse to move around the image.

A virtual digital slide of a bone marrow aspirate from a patient with myelodysplasia was made in both the fpx and QuickTime versions. Students, residents, and faculty judged both programs to be easy to use, to have easy zoom in and out features, to have excellent image quality, and to be a good educational tool. More people preferred the Apple QuickTime version to the fpx format. This virtual digital slide should provide educators with a good computer tool to simulate the microscopic examination of a glass slide.

BENEFIT TO PARTICIPANTS ATTENDING SESSION:

Participants attending this presentation will learn of an exciting new tool to teach histology and pathology. This virtual slide can replace glass and microscope laboratories, thus eliminating the need for breakable and expensive equipment. This technology can be adapted to either Web or CD-ROM presentation.

Dr. Jonathan Ben-Ezra
Department of Pathology
Virginia Commonwealth University
POB 980250
Richmond, VA 23298-0250
USA
Phone: 804-828-0902
Fax: 804-828-2812
Email: jbenezra@vcu.edu