Diagnostic Validation of a Whole-Slide Imaging Scanner in Cytological Samples: Diagnostic Accuracy and Comparison With Light Microscopy

Abstract

Digital slides created by whole-slide imaging scanners can be evaluated by pathologists located in remote sites, but the process must be validated before this technology can be applied to routine cytological diagnosis. The aim of this study was to validate a whole-slide imaging scanner for cytological samples. Sixty cytological samples, whose diagnoses were confirmed by gold-standard examinations (histology or flow cytometry), were digitalized using a whole-slide imaging scanner. Digital slides and glass slides were examined by 3 observers with different levels of cytopathological expertise. No significant differences were noted between digital and glass slides in regard to the number of cases correctly diagnosed, or the sensitivity, specificity, or diagnostic accuracy, irrespective of the observers' expertise. The agreements between the digital slides and the gold-standard examinations were moderate to substantial, while the agreements between the glass slides and the gold-standard examinations were substantial for all 3 observers. The intraobserver agreements between digital and glass slides were substantial to almost perfect. The interobserver agreements when evaluating digital slides were moderate between observers 1 and 2 and between observers 1 and 3 while they were substantial between observers 2 and 3. In conclusion, our study demonstrated that the digital slides produced by the wholeslide imaging scanner are adequate to diagnose cytological samples and are similar among clinical pathologists with differing levels of expertise.

Mitotic Figures—Normal, Atypical, and Imposters: A Guide to Identification

“…There is generally good agreement between WSI and light microscopy (LM) with regard to cytologic and histologic diagnosis and MC in animal and human tumors. 2,3,13,16,18,29,32,48,53,64 A better correlation was observed in cases with higher MCs as compared to those with lower MCs. 3 Some studies reported a trend toward underestimating the MC with WSI as compared to LM and attributed this to difficulty of identifying MF via WSI.…”

Validation of digital microscopy: Review of validation methods and sources of bias

“…43 For specific diagnostic tasks, such as identification of neoplastic processes, true positive (TP), true negative (TN), false positive (FP), and false negative (FN) can be defined and used for calculation of sensitivity . 20 A true gold standard, however, may not be available for all diagnostic pathology tasks. For example, a cytologic validation study may use histologic diagnoses or flow cytometric diagnoses (for lymphoid tumors) as a gold standard.…”

“…For example, a cytologic validation study may use histologic diagnoses or flow cytometric diagnoses (for lymphoid tumors) as a gold standard. 20,21 Although histologic and cytologic specimens may not always allow the same interpretation, histology is independent to cytology (as it is not used by the study pathologists) and is generally considered superior ("true" diagnosis) for most disease entities (there are some exceptions). Therefore, it may be used as a gold standard (GS) method to determine "equivalency" or "superiority" (as opposed to agreement or concordance) between DM and LM.…”

“…56 If multiple study participants are involved (which we certainly recommend), they can either examine the same or different cases. Examination of the same study case set will allow calculation of interobserver reproducibility (especially useful for simple modality comparison studies) and is easier for developing and conducting the study; 17,20,21,78 however, it may possibly lead to amplification of the same errors. Alternatively, having different pathologists each examine a different subset of study cases will increase the total number of cases and thereby the scope/ range and variance of the cases examined.…”

The Application, Challenges, and Advancement Toward Regulatory Acceptance of Digital Toxicologic Pathology: Results of the 7th ESTP International Expert Workshop (September 20-21, 2019)

“…25 Similar rates were identified for cases evaluating veterinary samples. 1,26 The overall interpretation is that diagnoses made using whole slide images emulated those made by conventional light microscopy.…”