Current state of whole slide imaging use in cytopathology: Pros and pitfalls

Abstract

Whole slide imaging (WSI) allows generation of large whole slide images and their navigation with zoom in and out like a true virtual microscope. It has become widely used in surgical pathology for many purposes, such as education and training, research activity, teleconsultation, and primary diagnosis. However, in cytopathology, the use of WSI has been lagging behind histology, mainly due to the cytological specimen's characteristics, as groups of cells of different thickness are distributed throughout the slide. To allow the same focusing capability of light microscope, slides have to be scanned at multiple focal planes, at the cost of longer scan times and larger file size. These are the main technical pitfalls of WSI for cytopathology, partly overcome by solutions like liquid‐based preparations. Validation studies for the use in primary diagnosis are less numerous and more heterogeneous than in surgical pathology. WSI has been proved effective for training students and successfully used in proficiency testing, allowing the creation of digital cytology atlases. Longer scan times are also a barrier for use in rapid on‐site evaluation, but WSI retains its advantages of easy sharing of images for consultation, multiple simultaneous viewing in different locations, the possibility of unlimited annotations and easy integration with medical records. Moreover, digital slides set the laboratory free from reliance on a physical glass slide, with no more concern of fading of stain or slide breakage. Costs are still a problem for small institutions, but WSI can also represent the beginning of a more efficient way of working.

Utilization of cytology smears improves success rates of RNA‐based next‐generation sequencing gene fusion assays for clinically relevant predictive biomarkers

“…Limitations to the use of direct smears for molecular testing include the necessity for additional validation and possible medicolegal issues in sacrificing lesional smear slides in the pursuit of test results. 20,44,45 With the expanding use of digital capabilities, diagnostic smear slides can be converted into digital slides by whole-slide imaging before testing, [46][47][48] thereby mitigating concerns over the consumption of diagnostic smears. In addition, several recent guidelines 35,36 for molecular testing have endorsed the use of non-CB cytologic substrates in addition to CB material.…”

Advantages of Using a Web-based Digital Platform for Kidney Preimplantation Biopsies

“…Another major barrier to taking on WSI for primary diagnosis is the cultural resistance experienced by a pathologist. [ 26 ] A large-scale adoption of WSI should be encouraged, particularly in the assessment of transplant biopsies, as the advantages pertain not only to clinical practice but also to scientific development and finally to the educational area.…”

Advances in Imaging Modalities, Artificial Intelligence, and Single Cell Biomarker Analysis, and Their Applications in Cytopathology

“…Cytologic preparation often uses whole cells smeared across a slide or made with a liquid-based preparation, causing 3-D overlap. The cytologic preparation requires evaluation of multiple z-planes, which takes more time to scan and review by a diagnostician (46,47). Proper validation studies and training will likely alleviate the pressures against adopting these digital systems for routine use in cytology.…”