Advantage of Z‐stacking for teleconsultation between the USA and Colombia

Abstract

Introduction There is an emerging need for telecytology in Colombia as the demand for cytopathology has increased. However, due to economic and technological constraints telecytology services are limited. Our aim was to evaluate the diagnostic feasibility of using whole slide imaging with and without Z‐stacking for telecytology in Colombia, South America. Methods Archival glass slides from 17 fine needle aspiration smears were digitized employing whole slide imaging (WSI) (Nanozoomer 2.0 HT, Hamamatsu) in one Z‐plane at 40x, and panoramic digital imaging (Panoptiq system, ViewsIQ) combining low‐magnification digital maps with embedded 40x Z‐stacks of representative regions of interest. Fourteen Colombian pathologists reviewed both sets of digital images. Diagnostic concordance, time to diagnosis, image quality (scale 1–10), usefulness of Z‐stacking, and technical difficulties were recorded. Results Image quality scored by pathologists was on average 8.3 for WSI and 8.7 for panoramic images with Z‐stacks (P = .03). However, diagnostic concordance was not impacted by image quality ranking. In the majority of cases (72.4%) pathologists deemed Z‐stacking to be diagnostically helpful. Technical issues related to Z‐stack video performance constituted only a minor proportion of technical problems reported. Slow downloads and crashing of files while viewing were mostly experienced with larger WSI files. Conclusion This study demonstrated that international telecytology for diagnostic purposes is feasible. Panoramic images had to be acquired manually, but were of suitable diagnostic quality and generated smaller image files associated with fewer technical errors. Z‐stacking proved to be useful in the majority of cases and is thus recommended for telecytology.

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

“…Differently from surgical pathology, despite numerous international telepathology consultation services available, 13 very few studies on telecytology consultations using WSI have been published. [39][40][41][42] However, for second opinion consultation, WSI in cytology retains the same advantages, with studies showing a high degree of feasibility and confidence once the system is fully in action. 41 In addition, there is still the need of a close collaboration between institutions and an important investment strategy in the technical part.…”

“…[39][40][41][42] However, for second opinion consultation, WSI in cytology retains the same advantages, with studies showing a high degree of feasibility and confidence once the system is fully in action. 41 In addition, there is still the need of a close collaboration between institutions and an important investment strategy in the technical part. 40,42 WSI provides a high-quality file that can be showing how the training with WSI is effective to make students able to pass the proficiency tests.…”

Smartphone-Assisted Telecytopathology: An Intraobserver Concordance Study

“…However, this makes the file image file size bulky. A recent paper by Mosquera-Zamudio et al [6] found an overall agreement of 58.8% to 88.2% between Colombian pathologists and the diagnosis given by a referral centre in United States by telecytology using whole slide imaging with Z stack technique. Most of the cytologists found the Z stacking to be diagnostically useful.…”

“…Most of the cytologists found the Z stacking to be diagnostically useful. Slower downloads and crashing of large files were some of the problems reported [6].…”

Video compression to support the expansion of whole-slide imaging into cytology

“…Although conservative data retention policies or selective scanning can help institutions overcome these barriers, collecting images that require scanning at multiple focal planes (or z-stacking) still represents a technical challenge for many laboratories, despite potentially significant diagnostic gains. 5 Modern WSI scanners often support z-stack scanning, but the storage requirements are typically an order of magnitude greater than for single-plane scans. As laboratories begin to rely on their image management needs being met by networked servers or the cloud, this also introduces the issue of increased bandwidth requirements to support z-stacking for live WSI viewing.…”