Evaluation and optimization for liquid-based preparation cytology in whole slide imaging

Area of Science:

• Digital pathology
• Cytopathology
• Whole slide imaging

Background:

• Cytology slides are thicker than surgical pathology slides, requiring multiple focal planes for adequate diagnosis.
• Multiple focal planes increase scanning time, evaluation time, and file size in whole slide imaging.
• This study evaluates methods to optimize whole slide imaging for cytology.

Purpose of the Study:

• To compare the multilayer stack method with the extended focus algorithm for whole slide imaging of cytology slides.
• To assess the impact of different scanning parameters on image quality, scan time, and file size.

Main Methods:

• Ten SurePath cervical cytology slides were scanned using three different scanners (Hamamatsu Nanozoomer, 3DHISTECH Mirax, Bioimagene iScan) at varying thicknesses (18, 24, 30 μm).
• Two methods were employed: multilayer stacking (Nanozoomer, iScan) and extended focus (Mirax).
• Scan times, file sizes, and image quality were recorded and compared.

Main Results:

• Multilayer stacks generated large files (1.58 gb to 9.3 gb) and long scan times (25-50 min).
• Extended focus resulted in smaller files (210 mb) and shorter scan times (13-20 min).
• Extended focus images showed significant loss of detail, impacting nuclear contour and chromatin assessment, while multilayer stacks offered comparable quality between scanners.

Conclusions:

• Multilayer stacks are inefficient for cytology whole slide imaging due to time and storage demands.
• Extended focus algorithms present significant image quality limitations for cytopathology.
• Further research is necessary to determine optimal focal plane strategies and their clinical utility in cytology.