Application of virtual microscopy in clinical cytopathology

Virtual microscopy (VM) refers to the use of an automated microscope and di gital imaging technology to scan, store, and view, glass slides. VM systems allow, the user to view a scanned image of the entire slide at multiple ma gnifications on a computer screen. We tested VM to evaluate its possible ut ility in diagnostic cytopathology. Ten cervical-vaginal monolayered prepara tions (Auto-Cyte (TM) preparation) were scanned using a BLISS (TM) (Bacus L aboratories Inc. Slide Scanner) system, Approximately 20-30% of the cellula r area of each slide was imaged. The cases were randomly chosen to include examples ranging from benign cellular changes (BCC) to high-grade squamous intraepithelial lesions (HSIL). The computer performed image tiling and fus ing of multiple JPEG images to create a high-quality VM slide. Six examiner s (two each of cytopathologists, senior residents, and cytotechnologists) b lindly evaluated the VM slides using an image server program ( WebSlide Bro wser (TM) thin client software). The cytopathologic diagnoses made on the V M slide were then compared to the original glass slide diagnoses. BLISS (TM ) took 36-100 min (avg. 58.4 min) to scan the selected fields in a glass sl ide with file sizes ranging from 23.1-83.6 AIR Time taken by the examiners to render a diagnosis ranged from 1-15 min (avg. 4.1 min) per case. The com bined diagnostic accuracy was 98.3%. Only one case of LSIL was missed by on e examiner. VM is a promising new tool, which gives a user the feel and sim ulated experience of an actual microscopic examination and provides a usefu l alternative to a glass slide in diagnostic cytopathology. Possible applic ations include: 1) second opinion consultation without transporting the gla ss slide, 2) education, 3) VM proficiency tests / board exams, and 4) telep athology. Shortcomings include 1) expensive initial setup, 2) inability to maintain an adequate focus in a thick smear with multiple levels, 3) large storage size of the VM slide, and 4) relatively long time needed to scan a slide. (C) 2001 Wiley-Liss, Inc.