Digital pathology for the routine diagnosis of renal diseases: a standard model

Abstract

Whole-slide imaging and virtual microscopy are useful tools implemented in the routine pathology workflow in the last 10 years, allowing primary diagnosis or second-opinions (telepathology) and demonstrating a substantial role in multidisciplinary meetings and education. The regulatory approval of this technology led to the progressive digitalization of routine pathological practice. Previous experiences on renal biopsies stressed the need to create integrate networks to share cases for diagnostic and research purposes. In the current paper, we described a virtual lab studying the routine renal biopsies that have been collected from 14 different Italian Nephrology centers between January 2014 and December 2019. For each case, light microscopy (LM) and immunofluorescence (IF) have been processed, analysed and scanned. Additional pictures (eg. electron micrographs) along with the final encrypted report were uploaded on the web-based platform. The number and type of specimens processed for every technique, the provisional and final diagnosis, and the turnaround-time (TAT) have been recorded. Among 826 cases, 4.5% were second opinion biopsies and only 4% were suboptimal/inadequate for the diagnosis. Transmission electron microscopy (TEM) has been performed on 41% of cases, in 22% changing the final diagnosis, in the remaining 78% contributed to the better definition of the disease. For light microscopy and IF the median TAT was of 2 working days, with only 8.6% with a TAT longer than 5 days. For TEM, the average TAT was 26 days (IQR 6-64). In summary, we systematically reviewed the 6-years long nephropathological experience of an Italian renal pathology service, where digital pathology is a definitive standard of care for the routine diagnosis of glomerulonephritides.

Imaging the Kidney with an Unconventional Scanning Electron Microscopy Technique: Analysis of the Subpodocyte Space in Diabetic Mice

“…Although our findings support the claim that SE-SEM evaluation is a powerful tool for analysing renal biopsies, the crucial role that TEM plays in diagnostic renal pathology is undisputed [27][28][29], and there is no doubt that SE-SEM does not achieve the resolution power of TEM. However, SE-SEM is a valuable alternative to TEM when high-resolution imaging of a large volume of the sample is needed or when the pathologist does not need (A-C) the identification of the glomerulus using light microscopy on toluidine blue stained 1 µm sections and then (D) the collection of 100 nm sections on copper TEM grids for (E-G) observation with TEM; (H-K) SE-SEM method protocol, including (H) collection of 1 µm sections on carboncoated slice and (I-K) observation by an ultra-high-resolution field-emission SEM of the semi-thin (1 µm) section.…”

“…Although our findings support the claim that SE-SEM evaluation is a powerful tool for analysing renal biopsies, the crucial role that TEM plays in diagnostic renal pathology is undisputed [27][28][29], and there is no doubt that SE-SEM does not achieve the resolution power of TEM. However, SE-SEM is a valuable alternative to TEM when high-resolution imaging of a large volume of the sample is needed or when the pathologist does not need to reach maximum magnifications for the purposes of the study.…”

A Survival Guide for the Rapid Transition to a Fully Digital Workflow: The “Caltagirone Example”

“…Finally, the adoption of computer-aided diagnostic and artificial-intelligence tools is allowing the construction of a digital hub based in Caltagirone ("House of the Science") that will coordinate the widest renal pathology network in Italy, collecting cases from an already established nephropathology service in the North of the country that migrated all the routine renal biopsy diagnoses to WSI in 2014 [32]. This will further guarantee an equal access to the best diagnostic renal pathology services without the need to move patients, glass slides or paraffin blocks around Italy, additionally constructing a reposi-tory of non-neoplastic renal diseases that can serve as an educational atlas as well as a research database.…”

A literature review of quality, costs, process-associated with digital pathology

“…Digital pathology was used only for educational or consulting purposes until their regulatory approval for clinical employment in routine pathological practice ( L’Imperio et al, 2020 ). In studies in the United States and Europe, the regulatory approval of digital pathology research results has been reported, and the similarity of WSI diagnosis to the pathological diagnosis (using a conventional microscope) has been confirmed ( L’Imperio et al, 2020 ).…”