Study on the Transformation Process of Thyroid Fine-Needle Aspiration Liquid-Based Cytology to Whole-Slide Image

Abstract

Objective: Analyse and summarise the reasons for failure in the digital acquisition of thyroid liquid-based cytology (LBC) slides and the technical challenges, and explore methods to obtain reliable and reproducible whole digital slide images for clinical thyroid cytology.

Method: Use the glass slide scanning imaging system to acquire whole-slide image (WSI) of thyroid LBC in sdpc format through different. Statistical analysis was conducted on the different acquisition methods, the quality of the glass slides, clinical and pathological characteristics of the case, TBSRTC grading and the quality of WSI.

Results: The WSI obtained by different scanning methods showed a high level of consistency in quality (W = 0.325, p < 0.001), especially between fully automatic scanning with different focus densities (W = 0.9, p < 0.001). A total of 2114 images were obtained through different methods of multi-layer fusion and multi-point focusing scanning, with scan success rates of 100.0%, 100.0%, 100.0% and 23.6%, respectively. The correlation between the quality of thyroid LBC glass slides and the image quality of thyroid LBC WSI was statistically significant (p < 0.001). The correlation between TBSRTC grading and the quality of thyroid LBC digital WSI was statistically significant (p < 0.001).

Conclusions: Although the quality of glass slides has a significant impact, the success rate and image quality of malignant tumour scanning are both high. Overall, the risk of missed diagnosis of malignant tumours is low. In the future, we also need to improve the performance and algorithm of the scanner in cases of sparse cells.

Keywords: liquid‐based cytology; scanner; the Bethesda system for reporting thyroid cytology; thyroid; whole‐slide image.

FIGURE 1

The technical roadmap.

FIGURE 2

Green and red dots represent the distribution of focal points, with green successfully focusing and red indicating defocus; (A) is fully automatic high‐density multi‐point focusing scanning, (B) is fully automatic medium‐density multi‐point focusing scanning, (C) is fully automatic low‐density multi‐point focusing scanning, (D) is manual multi‐point focusing scanning.

FIGURE 3

(A) shows that the cells were not completely dispersed during the preparation process, and thick cell nests appeared locally, leading to the focus being mainly on this area. The regions with thin cells or low coefficients failed to focus, resulting in blurred cells in the scan, as seen under high magnification in image (E); (B) shows overall uneven thickness, resulting in blurred cells in the scan, as seen under high magnification in image F; (C) indicates that during slide preparation, there was not enough glue or it was not thick enough, leading to a dry slide, which caused blurred cells due to defocusing, as seen under high magnification in image (G); (D) indicates a lack of cells, and even after successful manual focusing, local cells remain blurred, as seen under high magnification in image (H). (Liquid‐based thin sections, Papanicolaou stain).

FIGURE 4

(A–F) WSI under low magnification of I–VI grade, respectively; (G–L): Cytological morphology under high magnification of I–VI grade, respectively.