Validation of multiple whole slide imaging scanners based on the guideline from the College of American Pathologists Pathology and Laboratory Quality Center.
BACKGROUND
Whole slide imaging (WSI) produces a virtual image that can be transmitted electronically. This technology has clinical applications in situations in which glass slides are not readily available.


OBJECTIVE
To examine the results of a validation study performed using the draft version of the WSI clinical validation guideline recently released by the College of American Pathologists.


METHODS
Ten iScan Coreo Au scanners (Ventana Medical Systems, Tucson, Arizona) were validated, 6 with one set of 100 cases and 4 with a different set of 100 cases, for 1000 case examinations. The cases were selected consecutively from the following case types: internal consultations and malignancies and cases with frozen sections, special stains, and/or immunohistochemistry. Only key slides were scanned from each case. The slides were scanned at ×20 magnification. Pathologists reviewed the cases as both glass slides and WSI, with at least a 3-week washout period between viewings.


RESULTS
Intraobserver agreement between glass slides and WSI was present for 786 (79%) of the 1000 cases. Major discrepancies occurred in 18 cases (1.8%). κ statistics compiled for the subset of cases (n = 504; 50%) with concern for neoplasia showed excellent agreement (κ = 0.8782). Individual scanners performed similarly to one another. Analysis of the results revealed an area of concern: small focal findings.


CONCLUSIONS
The results were felt to validate the use of WSI for the intended applications in our multiinstitutional laboratory system, although scans at ×20 magnification may be insufficient for cases hinging on small focal findings, such as microorganisms and inflammatory processes.
From the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas.
Michael J
MJ
Thrall
Jana L
JL
Wimmer
Mary R
MR
Schwartz
D001706:Biopsy; D003952:Diagnostic Imaging / Q000295:instrumentation / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008853:Microscopy / Q000295:instrumentation / Q000379:methods; D009369:Neoplasms / Q000175:diagnosis*; D015588:Observer Variation; D010338:Pathology, Clinical / Q000295:instrumentation / Q000379:methods*; D010340:Pathology, Surgical / Q000295:instrumentation / Q000379:methods*; D019114:Remote Consultation; D012984:Software; D019113:Telepathology / Q000295:instrumentation / Q000379:methods; D057188:Workflow