Low-Cost Whole Slide Imaging for Routine Frozen Section Diagnostics
Adam J Horn, John J Baker, Mary F McGaughey, Kirk W Foster, Audrey J Lazenby. University of Nebraska Medical Center, Omaha, NE
Background: As the technology of whole slide imaging (WSI) has matured, there has been a reduction in size/cost of the instruments allowing for adoption at varied sites. Previous studies have evaluated WSI for the diagnostic accuracy of frozen sections (FS) for limited specimen types. Little has been published on the pre-analytic issues of WSI for routine FS use on all specimen types. We investigated a low-cost desktop whole slide imager for routine FS diagnosis of all specimen types, evaluating pre-analytic/analytic time, diagnostic accuracy, and technical issues.
Design: 35 FS specimens from 1 month were randomly selected. The archived H&E cryoblock slides (95 slides) were digitized at 20x using a low-cost desktop whole slide scanner. Tissue area (mm2) was calculated using the viewing software. Scan and post-scan image processing time was recorded. De-identified surgical requisitions with clinical information were provided to two senior surgical pathologists who reviewed the scanned slides on a single designated computer/monitor. The diagnosis, interpretation time, and comments were recorded.
Results: The average combined scan/process time was 9.8 min/slide and 26.6 min/specimen, ranging from 2.5-28 min/slide. The average tissue size was 216.3 mm2 with an average scan/image process time of 21.9 mm2/min. The scan time is directly proportional to the tissue size (Fig 1, r2=.78). The average interpretation time was 1.2 min/slide and 3.4 min/specimen. The concordance with the glass slide diagnosis was 97% for pathologist 1 (missed micromet in lymph node, 1 deferred) and 91% for pathologist 2 (missed micromets in lymph node and soft tissue). Technical issues included slides being dark/thick (6 slides), scanned tissue cut off near edge of slide (21 slides), and tissue out of focus (7 slides).
Conclusions: 1) WSI for FS interpretation yields good-excellent diagnostic accuracy. 2) Analytic time is similar to light microscopy. 3) Using a currently available desktop scanner, scan time is very long for large specimens, which may limit usefulness in routine practice. 4) Slides of large pieces of tissue prepared via cryostat sometimes yield thick, folded sections with tissue placed at the edge of a slide, and thus there are more technical issues with WSI (tissue cut off, out of focus) compared to paraffin.
Monday, March 4, 2013 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 249, Monday Morning