Primary frozen section diagnosis by robotic microscopy and virtual slide telepathology: the University Health Network experience

Integrating digital pathology into clinical practice

The field of anatomic pathology has been evolving in the last few decades and the advancements have been largely fostered by innovative technology. Immunohistochemistry enabled a paradigm shift in discovery and diagnostic evaluation, followed by booming genomic advancements which allowed for submicroscopic pathologic characterization, and now the field of digital pathology coupled with machine learning and big data acquisition is paving the way to revolutionize the pathology medical domain. Whole slide imaging (WSI) is a disruptive technology where glass slides are digitized to produce on-screen whole slide images. Specifically, in the past decade, there have been significant advances in digital pathology systems that have allowed this technology to promote integration into clinical practice. Whole slide images (WSI), or digital slides, can be viewed and navigated comparable to glass slides on a microscope, as digital files. Whole slide imaging has increased in adoption among pathologists, pathology departments, and scientists for clinical, educational, and research initiatives. Integration of digital pathology systems requires a coordinated effort with numerous stakeholders, not only within the pathology department, but across the entire enterprise. Each pathology department has distinct needs, use cases and blueprints, however the framework components and variables for successful clinical integration can be generalized across any organization seeking to undergo a digital transformation at any scale. This article will review those components and considerations for integrating digital pathology systems into clinical practice.

Validation of a Portable Whole-Slide Imaging System for Frozen Section Diagnosis

Background

Frozen section (FS) diagnosis is one of the promising applications of digital pathology (DP). However, the implementation of an appropriate and economically viable DP solution for FS in routine practice is challenging. The objective of this study was to establish the non-inferiority of whole-slide imaging (WSI) versus optical microscopy (OM) for FS diagnosis using a low cost and portable DP system.

Materials and Methods

A validation study to investigate the technical performance and diagnostic accuracy of WSI versus OM for FS diagnosis was performed using 60 FS cases[120 slides i.e, 60 hematoxylin and eosin (H & E) and 60 toluidine blue (TOLB)]. The diagnostic concordance, inter- and intra-observer agreement for FS diagnosis by WSI versus OM were recorded.

Results

The first time successful scanning rate was 89.1% (107/120). Mean scanning time per slide for H and E and TOLB slide was 1:47 min (range; 0:22-3: 21 min) and 1:46 min (range; 0:21-3: 20 min), respectively. Mean storage space per slide for H and E and TOLB slide was 0.83 GB (range: 0.12-1.73 GB) and 0.71 GB (range: 0.11-1.66 GB), respectively. Considering major discrepancies, the overall diagnostic concordance for OM and WSI, when compared with the reference standard, was 95.42% and 95.83%, respectively. There was almost perfect intra as well as inter-observer agreement (k ≥ 0.8) among 4 pathologists between WSI and OM for FS diagnosis. Mean turnaround time (TAT) of 14:58 min was observed using WSI for FS diagnosis, which was within the College of American Pathologists recommended range for FS reporting. The image quality was average to best quality in most of the cases.

Conclusion

WSI was noninferior to OM for FS diagnosis across various specimen types. This portable WSI system can be safely adopted for routine FS diagnosis and provides an economically viable alternative to high-end scanners.

Disruptive innovations in the clinical laboratory: catching the wave of precision diagnostics

Disruptive innovation is an invention that disrupts an existing market and creates a new one by providing a different set of values, which ultimately overtakes the existing market. Typically, when disruptive innovations are introduced, their performance is initially less than existing standard technologies, but because of their ability to bring the cost down, and with gradual improvement, they end up replacing established service standards.Disruptive technologies have their fingerprints in health care. Pathology and laboratory medicine are fertile soils for disruptive innovations because they are heavily reliant on technology. Disruptive innovations have resulted in a revolution of our diagnostic ability and will take laboratory medicine to the next level of patient care. There are several examples of disruptive innovations in the clinical laboratory. Digitizing pathology practice is an example of disruptive technology, with many advantages and an extended scope of applications. Next-generation sequencing can be disruptive in two ways. The first is by replacing an array of laboratory tests, which each requires expensive and specialized instruments and expertise, with a single cost-effective technology. The second is by disrupting the current paradigm of the clinical laboratory as a diagnostic service by taking it into a new era of preventive or primary care pathology. Other disruptive innovations include the use of dry chemistry reagents in chemistry analyzers and also point of care testing. The use of artificial intelligence is another promising disruptive innovation that can transform the future of pathology and laboratory medicine. Another emerging disruptive concept is the integration of two fields of medicine to create an interrelated discipline such as "histogenomics and radiohistomics." Another recent disruptive innovation in laboratory medicine is the use of social media in clinical practice, education, and publication.There are multiple reasons to encourage disruptive innovations in the clinical laboratory, including the escalating cost of health care, the need for better accessibility of diagnostic care, and the increased demand on the laboratory in the era of precision diagnostics. There are, however, a number of challenges that need to be overcome such as the significant resistance to disruptive innovations by current technology providers and governmental regulatory bodies. The hesitance from health care providers and insurance companies must also be addressed.Adoption of disruptive innovations requires a multifaceted approach that involves orchestrated solutions to key aspects of the process, including creating successful business models, multidisciplinary collaborations, and innovative accreditation and regulatory oversight. It also must be coupled with successful commercialization plans and modernization of health care structure. Fostering a culture of disruptive innovation requires establishing unique collaborative models between academia and industry. It also requires uncovering new sources of unconventional funding that are open to high-risk high-reward projects. It should also be matched with innovative thinking, including new approaches for delivery of care and identifying novel cohorts of patients who can benefit from disruptive technology.

Whole Slide Imaging: Technology and Applications

Pathology has benefited from advanced innovation with novel technology to implement a digital solution. Whole slide imaging is a disruptive technology where glass slides are scanned to produce digital images. There have been significant advances in whole slide scanning hardware and software that have allowed for ready access of whole slide images. The digital images, or whole slide images, can be viewed comparable to glass slides in a microscope, as digital files. Whole slide imaging has increased in adoption among pathologists, pathology departments, and scientists for clinical, educational, and research initiatives. Worldwide usage of whole slide imaging has grown significantly. Pathology regulatory organizations (ie, College of American Pathologists) have put forth guidelines for clinical validation, and the US Food and Drug Administration have also approved whole slide imaging for primary diagnosis. This article will review the digital pathology ecosystem and discuss clinical and nonclinical applications of its use.

The Next Generation Robotic Microscopy for Intraoperative Teleneuropathology Consultation

Introduction

Teleneuropathology at our institution evolved over the last 17 years from using static to dynamic robotic microscopy. Historically (2003-2007), using older technology, the deferral rate was 19.7%, and the concordance was 81% with the final diagnosis. Two years ago, we switched to use hybrid robotic devices to perform these intraoperative (IO) consultations because our older devices were obsolete. The aim of this study was to evaluate the impact this change had on our deferral and concordance rates with teleneuropathology using this newer instrument.

Materials and Methods

Aperio LV1 4-slide capacity hybrid robotic scanners with an attached desktop console (Leica Biosystems, Vista, CA, USA) and GoToAssist (v4.5.0.1620, Boston, MA, USA) were used for IO telepathology cases. A cross-sectional comparative study was conducted comparing teleneuropathology from three remote hospitals (193 cases) to IO neuropathology consultation performed by conventional glass slide examination at a light microscope (310 cases) from the host hospital. Deferral and concordance rates were compared to final histopathological diagnoses.

Results

The deferral rate for IO teleneuropathology was 26% and conventional glass slide 24.24% (P = 0.58). The concordance rate for teleneuropathology was 93.94%, which was slightly higher than 89.09% for conventional glass slides (P = 0.047).

Conclusion

The new hybrid robotic device for performing IO teleneuropathology interpretations at our institution was as effective as conventional glass slide interpretation. While we did observe a noticeable change in the deferral rate compared to prior years, we did appreciate the marked improvement of the concordance rate using this new hybrid scanner.

Guidance for Remote Reporting of Digital Pathology Slides During Periods of Exceptional Service Pressure: An Emergency Response from the UK Royal College of Pathologists

Pathology departments must rise to new staffing challenges caused by the coronavirus disease-19 pandemic and may need to work more flexibly for the foreseeable future. In light of this, many pathologists and departments are considering the merits of remote or home reporting of digital cases. While some individuals have experience of this, little work has been done to determine optimum conditions for home reporting, including technical and training considerations. In this publication produced in response to the pandemic, we provide information regarding risk assessment of home reporting of digital slides, summarize available information on specifications for home reporting computing equipment, and share access to a novel point-of-use quality assurance tool for assessing the suitability of home reporting screens for digital slide diagnosis. We hope this study provides a useful starting point and some practical guidance in a difficult time. This study forms the basis of the guidance issued by the Royal College of Pathologists, available at: https://www.rcpath.org/uploads/assets/626ead77-d7dd-42e1-949988e43dc84c97/RCPath-guidance-for-remote-digital-pathology.pdf.

Systematic Review of the Use of Telepathology During Intraoperative Consultation

OBJECTIVE

To compare studies that used telepathology systems vs conventional microscopy for intraoperative consultation (frozen-section) diagnosis.

METHODS

A total of 56 telepathology studies with 13,996 cases in aggregate were identified through database searches.

RESULTS

The concordance of telepathology with the reference standard was generally excellent, with a weighted mean of 96.9%. In comparison, we identified seven studies using conventional intraoperative consultation that showed a weighted mean concordance of 98.3%. Evaluation of the risk of bias showed that most of these studies were low risk.

CONCLUSIONS

Despite limitations such as variation in reporting and publication bias, this systematic review provides strong support for the safety of using telepathology for intraoperative consultations.

Optical Versus Virtual Microscope for Medical Education: A Systematic Review

Many technological innovations have changed the traditional practice of medical education and clinical practice. Whole slide imaging (WSI) technology provided an unique way of viewing conventional glass slides in histology and pathology laboratories. The WSI technology digitalized glass slide images and made them readily accessible via the Internet using tablets or computers. Users utilized the pan-and-zoom function to view digital images of slides, also referred to as the virtual microscope (VM), simulating use of an optical microscope (OM). Several articles have reported various outcomes on the utility of VM in teaching laboratories. Recently, the Royal College of Physicians and Surgeons of Canada certification examinations for anatomical pathologists ha completely adopted VM for the national licensing examination. To better inform medical educators, there is an urgent need for more structured reviews to draw evidence-based conclusions on the effectiveness of VM and learner's perceptions, in comparison to OM. The current study provides a descriptive summary of published outcomes using the systematic review approach. In conclusion, medical students' performance was improved with adoption of VM into the curriculum and recognized as a preferred learning modality, compared to OM. On the contrary, resident learners' performance was comparable between using OM and VM, with OM being the favored slide-viewing modality.

Comprehensive Study of Telecytology Using Robotic Digital Microscope and Single Z-Stack Digital Scan for Fine-Needle Aspiration-Rapid On-Site Evaluation

Background:

The current technology for remote assessment of fine-needle aspiration-rapid on-site evaluation (FNA-ROSE) is limited. Recent advances may provide solutions. This study compared the performance of VisionTek digital microscope (VDM) (Sakura, Japan) and Hamamatsu NanoZoomer C9600-12 single Z-stack digital scan (SZDS) to conventional light microscopy (CLM) for FNA-ROSE.

Methods:

We assembled sixty FNA cases from the thyroid (n = 16), lymph node (n = 16), pancreas (n = 9), head and neck (n = 9), salivary gland (n = 5), lung (n = 4), and rectum (n = 1) based on a single institution's routine workflow. One Diff-Quik-stained slide was selected for each case. Two board-certified cytopathologists independently evaluated the cases using VDM, SZDS, and CLM. A “washout” period of at least 14 days was placed between the reviews. The results were categorized into satisfactory versus unsatisfactory for adequacy assessment (AA) and unsatisfactory, benign, atypical, suspicious, and malignant for preliminary diagnosis (PD).

Results:

For AA, the Cohen's kappa statistics (CKS) scores of intermodality agreement (IMA) were 0.74–0.94 (CLM vs. VDM) and 0.86–1 (CLM vs. SZDS). The discordant rates of IMA were 3.3% (4/120) for VDM versus CLM, and 1.7% (2/120) for SZDS versus CLM. For PD, the CKS scores of IMA ranged 0.7–0.93. The overall discordant rates of IMA were 15% (18/120) for CLM versus VDM and 10.8% (13/120) for CLM versus SZDS. The discordant rates of IMA with 2 or higher degrees were 5.8% (7/120) for CLM versus VDM and 1.7% (2/120) for CLM versus SZDS. The average time spent per slide was 270 s for VDM, significantly longer than that for CLM (113 s) or for SZDS (122 s).

Conclusions:

Our data demonstrate that both VDM and SZDS are suitable to provide AA and reasonable PD evaluation. VDM, however, has a significantly longer turnaround time and worse diagnostic performance. The study demonstrates both the potentials and challenges of using VDM and SZDS for FNA-ROSE.

Telepathology Impacts and Implementation Challenges: A Scoping Review

CONTEXT

Telepathology is a particular form of telemedicine that fundamentally alters the way pathology services are delivered. Prior reviews in this area have mostly focused on 2 themes, namely technical feasibility issues and diagnosis accuracy.

OBJECTIVES

To synthesize the literature on telepathology implementation challenges and broader organizational and societal impacts and to propose a research agenda to guide future efforts in this domain.

DATA SOURCES

Two complementary databases were systematically searched: MEDLINE (PubMed) and ABI/INFORM (ProQuest). Peer-reviewed articles and conference proceedings were considered. The final sample consisted of 159 papers published between 1992 and 2013.

CONCLUSIONS

This review highlights the diversity of telepathology networks and the importance of considering these distinctions when interpreting research findings. Various network structures are associated with different benefits. Although the dominant rationale in single-site projects is financial, larger centralized and decentralized telepathology networks are targeting a more diverse set of benefits, including extending access to pathology to a whole region, achieving substantial economies of scale in workforce and equipment, and improving quality by standardizing care. Importantly, our synthesis reveals that the nature and scale of encountered implementation challenges also varies depending on the network structure. In smaller telepathology networks, organizational concerns are less prominent, and implementers are more focused on usability issues. As the network scope widens, organizational and legal issues gain prominence.

Validation of Whole-Slide Imaging for Histolopathogical Diagnosis: Current State

Rapid advances in informatics and technological improvements have led to the development of high-throughput whole-slide imaging (WSI) scanners able to produce high-quality digital images, which allow achieving a correct diagnosis of the biopsies using virtual viewers. This technology is currently prepared to be introduced in the departments of pathology for routine diagnosis. The aim of this review is to analyze the current evidence regarding the use of WSI in primary or routine diagnosis in the different subspecialties of pathology. An increasing number of studies have shown almost perfect inter- and intraobserver agreement between the diagnoses obtained with WSI and the classical diagnoses based on conventional light microscopy. The only exception seems to be cytology, which still requires some technological development. Although validation studies are needed in some areas of pathology, growing evidence indicates that WSI is a reliable tool for routine diagnosis. Pathologists have a positive perception of the ergonomics of the workstations, the low magnification of WSI and the possibility of making annotations and measurements. WSI can be used from any device and anywhere, thereby providing great opportunities for teleconsultation. New technologies such as the recognition of histopathology patterns using image analysis may facilitate diagnosis and improve the reproducibility among pathologists in the future.

Virtual slide telepathology with scanner systems for intraoperative frozen-section consultation

Telepathology provides pathology services over a distance using digital imaging and telecommunication for primary diagnostic practice, including intraoperative frozen sections. Virtual slide technology provides digitizing of histological slides by scanner systems and improved remote assessment substantially. In this retrospective study, diagnostic accuracy of intraoperative frozen sections assessed as virtual slide was determined. Tissue assessment was mainly requested for urological, gynecological and dermatological resections. Issues of time consumption, cost and cost effectiveness of this diagnostic method are discussed. 1204 intraoperative frozen sections were conducted in the course of this study at our department over a period of 2.5 years. 98.59% of all intraoperative frozen sections were accurately diagnosed in the initial telepathological assessment. Tumor affection was present in 15.6% of frozen sections, in 174 instances already assessed in the initial slides (sensitivity 92.6%). Discrepant diagnoses compared to the final diagnosis occurred in 1.41%. Our determined averaged time for virtual slide technology of 10.58±8.19min can be ranged in well. Our study did not allow a full economic assessment, but some preliminary insights are pointed out. The quality of services is highly acceptable and the investment costs and the labor cost of virtual slide technology are lower than those of robotic microscopy.

Multi-institutional comparison of whole slide digital imaging and optical microscopy for interpretation of hematoxylin-eosin-stained breast tissue sections

CONTEXT

Whole slide imaging (WSI) is now used for educational purposes, for consultation, and for archiving and quantitation of immunostains. However, it is not routinely used for the primary diagnosis of hematoxylin-eosin-stained tissue sections.

OBJECTIVE

To compare WSI using the Aperio digital pathology system (Aperio Technologies, Inc, Vista, California) with optical microscopy (OM) for the interpretation of hematoxylin-eosin-stained tissue sections of breast lesions.

DESIGN

The study was conducted at 3 clinical sites; 3 breast pathologists interpreted 150 hematoxylin-eosin-stained slides at each site, 3 times each by WSI and 3 times each by OM. For WSI, slides were scanned using an Aperio ScanScope and interpreted on a computer monitor using Aperio ImageScope software and Aperio Spectrum data management software. Pathologic interpretations were recorded using the College of American Pathologists breast checklist. WSI diagnoses were compared with OM diagnoses for accuracy, precision (interpathologist variation), and reproducibility (intrapathologist variation). Results were considered accurate only if the interpretation matched exactly between WSI and OM. The proportion of accurate results reported by each pathologist was expressed as a percentage for the comparison of the 2 platforms.

RESULTS

The accuracy of WSI for classifying lesions as not carcinoma or as noninvasive (ductal or lobular) or invasive (ductal, lobular, or other) carcinoma was 90.5%. The accuracy of OM was 92.1%. The precision and reproducibility of WSI and OM were determined on the basis of pairwise comparisons (3 comparisons for each slide, resulting in 36 possible comparisons). The overall precision of WSI was 90.5% in comparison with 92.1% for OM; reproducibility of WSI was 91.6% in comparison with 94.5% for OM, respectively.

CONCLUSIONS

In this study, we demonstrated that WSI and OM have similar accuracy, precision, and reproducibility for interpreting hematoxylin-eosin-stained breast tissue sections. Further clinical studies using routine surgical pathology specimens would be useful to confirm these findings and facilitate the incorporation of WSI into diagnostic practice.

Evaluation of immunohistochemical staining using whole-slide imaging for HER2 scoring of breast cancer in comparison with real glass slides

Whole-slide imaging (WSI) has been used for education and histological image preservation, and several studies have also reported its validity for practical pathological diagnosis. However, such studies employed materials stained with hematoxylin-eosin (HE), and very few attempts have been made to use immunohistochemically stained materials for diagnostic purposes. In the present study, we investigated the availability of WSI diagnosis for immunohistochemically stained materials in place of routine glass slides. Thirty pathologists participated in a trial of HER2 expression diagnosis using WSI and compared the results with those obtained by light microscopy. The validity of WSI diagnosis (interobserver agreement) was rated as 'substantial' in comparison with glass slide diagnosis (κ-value = 0.719). There was a tendency for observers to assign higher scores with WSI than with glass slides, probably because WSI requires slides to be scanned into a computer and observed via a monitor. Although we were able to demonstrate the potential utility of WSI for diagnosing immunostained materials, it must be borne in mind that there are some differences in visualization between WSI and glass slides.

Digital imaging in pathology--current applications and challenges

Conventional histopathology is rapidly shifting towards digital integration. Will microscopes (and pathologists) soon be obsolete? Or are we dealing with just another image modality that leaves the core of tissue diagnosis intact? This article provides an overview of current digital pathology applications and research with emphasis on whole slide imaging (WSI). Static or interactive digital pathology work stations already can be used for many purposes, e.g. telepathology expert consultations, frozen section diagnosis in remote areas, cytology screening, quality assurance, diagnostic validations for clinical trials, quantitation of hormone receptor or HER2 studies in breast cancer, or three-dimensional visualization of anatomical structures, among others. Changes of workflow in histology laboratories are beginning to enable digital image acquisition and WSI in a routine setting. WSI plays an increasing role in pathology education, glass slide boxes in medical schools are being replaced by digital slide collections; digital slide seminars and virtual microscopy are used for postgraduate and continuing medical education in pathology. Research and efforts to validate WSI systems for diagnostic settings are ongoing.

Digital slides and ACGME resident competencies in anatomic pathology: An altered paradigm for acquisition and assessment

Whole slide digital imaging technology has matured considerably over the past decade. Applications in pathology education are widespread and are rapidly transforming the manner in which medical students learn pathology and histology, and they have a novel and significant impact on postgraduate continuing medical education. Whole slide digital images for use in pathology graduate education have been slower in adoption and remain much less widespread. Emphasis on professional competency by the Accreditation Council on Graduate Medical Education (ACGME) and credentialing organizations, however, appear poised to significantly increase. The convergence of these two forces is propitious for pathology training. This article examines the opportunities for the use of whole slide images (WSI) in pathology residency training along with the developing potential uses in each of the areas of competency, as categorized by the ACGME. Barriers to WSI adoption in the pathology community are identified along with potentially significant promoters for adoption in training and practice. Current literature and recent presentations are reviewed. Digital pathology coupled with emphasis on competency is a shift of tremendous magnitude that can dramatically improve our abilities to help trainees acquire, demonstrate, and maintain the skills to practice pathology in the generation ahead.

Digital pathology: current status and future perspectives

During the last decade pathology has benefited from the rapid progress of image digitizing technology. The improvement in this technology had led to the creation of slide scanners which are able to produce whole slide images (WSI) which can be explored by image viewers in a way comparable to the conventional microscope. The file size of the WSI ranges from a few megabytes to several gigabytes, leading to challenges in the area of image storage and management when they will be used routinely in daily clinical practice. Digital slides are used in pathology for education, diagnostic purposes (clinicopathological meetings, consultations, revisions, slide panels and, increasingly, for upfront clinical diagnostics) and archiving. As an alternative to conventional slides, WSI are generally well accepted, especially in education, where they are available to a large number of students with the full possibilities of annotations without the problem of variation between serial sections. Image processing techniques can also be applied to WSI, providing pathologists with tools assisting in the diagnosis-making process. This paper will highlight the current status of digital pathology applications and its impact on the field of pathology.