The Landscape of Digital Pathology in Transplantation: From the Beginning to the Virtual E-Slide

Abstract

Background: Digital pathology has progressed over the last two decades, with many clinical and nonclinical applications. Transplantation pathology is a highly specialized field in which the majority of practicing pathologists do not have sufficient expertise to handle critical needs. In this context, digital pathology has proven to be useful as it allows for timely access to expert second-opinion teleconsultation. The aim of this study was to review the experience of the application of digital pathology to the field of transplantation. Methods: Papers on this topic were retrieved using PubMed as a search engine. Inclusion criteria were the presence of transplantation setting and the use of any type of digital image with or without the use of image analysis tools; the search was restricted to English language papers published in the 25 years until December 31, 2018. Results: Literature regarding digital transplant pathology is mostly about the digital interpretation of posttransplant biopsies (75 vs. 19), with 15/75 (20%) articles focusing on agreement/reproducibility. Several papers concentrated on the correlation between biopsy features assessed by digital image analysis (DIA) and clinical outcome (45/75, 60%). Whole-slide imaging (WSI) only appeared in recent publications, starting from 2011 (13/75, 17.3%). Papers dealing with preimplantation biopsy are less numerous, the majority (13/19, 68.4%) of which focus on diagnostic agreement between digital microscopy and light microscopy (LM), with WSI technology being used in only a small quota of papers (4/19, 21.1%). Conclusions: Overall, published studies show good concordance between digital microscopy and LM modalities for diagnosis. DIA has the potential to increase diagnostic reproducibility and facilitate the identification and quantification of histological parameters. Thus, with advancing technology such as faster scanning times, better image resolution, and novel image algorithms, it is likely that WSI will eventually replace LM.

Development of an Automatic Measurement Method for CD8 and PD-1 Positive T Cells Using Image Analysis Software

“…In particular, the development of suitable imaging analysis software focusing on TIL enumeration has not yet been successful; thus, manual measurements of TIL numbers after ICB therapy are becoming an increasingly large load to working pathologists. Additionally, high variability among observers and limited reproducibility are inevitable challenges to overcome (20).…”

Whole Slide Imaging and Its Applications to Histopathological Studies of Liver Disorders

“…In the post-transplantation phase, monitoring of the allograft inside the patient is vital for continued healthy functioning of the liver graft in the patient, as a number of post-transplantation complications can arise, including infection of the graft or rejection of the host to the graft which should be detected promptly. For all aspects of the assessment, conventional light microscopy remains the golden standard (41), although, as discussed before, inter-observer variability have shown to be suboptimal in this process due to the challenging nature of the assessment (42).…”

“…Several studies have been conducted to investigate the additional value of WSI over conventional light microscopy in the transplantation medicine setting. Recently, Girolami and colleagues have reviewed the current literature on this topic for both liver transplants, but also for other types of organ transplantation (42). The overall conclusion is that digital pathology (mainly WSI, especially recently, and otherwise highly related technologies) has a good correlation with conventional light microscopy but with a higher potential when it comes to inter-observer concordance (42).…”

“…Recently, Girolami and colleagues have reviewed the current literature on this topic for both liver transplants, but also for other types of organ transplantation (42). The overall conclusion is that digital pathology (mainly WSI, especially recently, and otherwise highly related technologies) has a good correlation with conventional light microscopy but with a higher potential when it comes to inter-observer concordance (42). This is because digital images of whole tissue sections are more easily shared and annotated, facilitating constructive collaboration on tissue assessment (42).…”

“…As WSI technology improves over time, the expectation is that within a foreseeable amount of time, digital pathology will overtake traditional forms of pathology in the field of organ transplantation and will ultimately lead to better patient-care (42). Also in the histopathologic assessment of allograft biopsies during monitoring, digital whole-slide approaches toward imaging open up possibilities of computational assessment of large tissue sections.…”