Integration and acceleration of virtual microscopy as the key to successful implementation into the routine diagnostic process

Continuing Undergraduate Pathology Medical Education in the Coronavirus Disease 2019 (COVID-19) Global Pandemic: The Johns Hopkins Virtual Surgical Pathology Clinical Elective

CONTEXT.—

In the early months of the response to the coronavirus disease 2019 (COVID-19) pandemic, the Johns Hopkins University School of Medicine (JHUSOM) (Baltimore, Maryland) leadership reached out to faculty to develop and implement virtual clinical clerkships after all in-person medical student clinical experiences were suspended.

OBJECTIVE.—

To develop and implement a digital slide-based virtual surgical pathology (VSP) clinical elective to meet the demand for meaningful and robust virtual clinical electives in response to the temporary suspension of in-person clinical rotations at JHUSOM.

DESIGN.—

The VSP elective was modeled after the in-person surgical pathology elective to include virtual previewing and sign-out with standardized cases supplemented by synchronous and asynchronous pathology educational content.

RESULTS.—

Validation of existing Web communications technology and slide-scanning systems was performed by feasibility testing. Curriculum development included drafting of course objectives and syllabus, Blackboard course site design, electronic-lecture creation, communications with JHUSOM leadership, scheduling, and slide curation. Subjectively, the weekly schedule averaged 35 to 40 hours of asynchronous, synchronous, and independent content, approximately 10 to 11 hours of which were synchronous. As of February 2021, VSP has hosted 35 JHUSOM and 8 non-JHUSOM students, who have provided positive subjective and objective course feedback.

CONCLUSIONS.—

The Johns Hopkins VSP elective provided meaningful clinical experience to 43 students in a time of immense online education need. Added benefits of implementing VSP included increased medical student exposure to pathology as a medical specialty and demonstration of how digital slides have the potential to improve standardization of the pathology clerkship curriculum.

Digital Microscopy, Image Analysis, and Virtual Slide Repository

Advancements in technology and digitization have ushered in novel ways of enhancing tissue-based research via digital microscopy and image analysis. Whole slide imaging scanners enable digitization of histology slides to be stored in virtual slide repositories and to be viewed via computers instead of microscopes. Easier and faster sharing of histologic images for teaching and consultation, improved storage and preservation of quality of stained slides, and annotation of features of interest in the digital slides are just a few of the advantages of this technology. Combined with the development of software for digital image analysis, digital slides further pave the way for the development of tools that extract quantitative data from tissue-based studies. This review introduces digital microscopy and pathology, and addresses technical and scientific considerations in slide scanning, quantitative image analysis, and slide repositories. It also highlights the current state of the technology and factors that need to be taken into account to insure optimal utility, including preanalytical considerations and the importance of involving a pathologist in all major steps along the digital microscopy and pathology workflow.

Digital image analysis in breast pathology-from image processing techniques to artificial intelligence

Breast cancer is the most common malignant disease in women worldwide. In recent decades, earlier diagnosis and better adjuvant therapy have substantially improved patient outcome. Diagnosis by histopathology has proven to be instrumental to guide breast cancer treatment, but new challenges have emerged as our increasing understanding of cancer over the years has revealed its complex nature. As patient demand for personalized breast cancer therapy grows, we face an urgent need for more precise biomarker assessment and more accurate histopathologic breast cancer diagnosis to make better therapy decisions. The digitization of pathology data has opened the door to faster, more reproducible, and more precise diagnoses through computerized image analysis. Software to assist diagnostic breast pathology through image processing techniques have been around for years. But recent breakthroughs in artificial intelligence (AI) promise to fundamentally change the way we detect and treat breast cancer in the near future. Machine learning, a subfield of AI that applies statistical methods to learn from data, has seen an explosion of interest in recent years because of its ability to recognize patterns in data with less need for human instruction. One technique in particular, known as deep learning, has produced groundbreaking results in many important problems including image classification and speech recognition. In this review, we will cover the use of AI and deep learning in diagnostic breast pathology, and other recent developments in digital image analysis.

The Empirical Foundations of Telepathology: Evidence of Feasibility and Intermediate Effects

INTRODUCTION

Telepathology evolved from video microscopy (i.e., "television microscopy") research in the early 1950s to video microscopy used in basic research in the biological sciences to a basic diagnostic tool in telemedicine clinical applications. Its genesis can be traced to pioneering feasibility studies regarding the importance of color and other image-based parameters for rendering diagnoses and a series of studies assessing concordance of virtual slide and light microscopy diagnoses. This article documents the empirical foundations of telepathology.

METHODS

A selective review of the research literature during the past decade (2005-2016) was conducted using robust research design and adequate sample size as criteria for inclusion.

CONCLUSIONS

The evidence regarding feasibility/acceptance of telepathology and related information technology applications has been well documented for several decades. The majority of evidentiary studies focused on intermediate outcomes, as indicated by comparability between telepathology and conventional light microscopy. A consistent trend of concordance between the two modalities was observed in terms of diagnostic accuracy and reliability. Additional benefits include use of telepathology and whole slide imaging for teaching, research, and outreach to resource-limited countries. Challenges still exist, however, in terms of use of telepathology as an effective diagnostic modality in clinical practice.

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.

iPathology cockpit diagnostic station: validation according to College of American Pathologists Pathology and Laboratory Quality Center recommendation at the Hospital Trust and University of Verona

Background

Validation of digital whole slide images is crucial to ensure that diagnostic performance is at least equivalent to that of glass slides and light microscopy. The College of American Pathologists Pathology and Laboratory Quality Center recently developed recommendations for internal digital pathology system validation. Following these guidelines we sought to validate the performance of a digital approach for routine diagnosis by using an iPad and digital control widescreen-assisted workstation through a pilot study.

Methods

From January 2014, 61 histopathological slides were scanned by ScanScope Digital Slides Scanner (Aperio, Vista, CA). Two independent pathologists performed diagnosis on virtual slides in front of a widescreen by using two computer devices (ImageScope viewing software) located to different Health Institutions (AOUI Verona) connected by local network and a remote image server using an iPad tablet (Aperio, Vista, CA), after uploading the Citrix receiver for iPad. Quality indicators related to image characters and work-flow of the e-health cockpit enterprise system were scored based on subjective (high vs poor) perception. The images were re-evaluated two weeks apart.

Results

The whole glass slides encountered 10 liver: hepatocarcinoma, 10 renal carcinoma, 10 gastric carcinoma and 10 prostate biopsies: adenocarcinoma, 5 excisional skin biopsies: melanoma, 5 lymph-nodes: lymphoma. 6 immuno- and 5 special stains were available for intra- and internet remote viewing. Scan times averaged two minutes and 54 seconds per slide (standard deviation 2 minutes 34 seconds). Megabytes ranged from 256 to 680 (mean 390) per slide storage. Reliance on glass slide, image quality (resolution and color fidelity), slide navigation time, simultaneous viewers in geographically remote locations were considered of high performance score. Side by side comparisons between diagnosis performed on tissue glass slides versus widescreen were excellent showing an almost perfect concordance (0.81, kappa index).

Conclusions

We validated our institutional digital pathology system for routine diagnostic facing with whole slide images in a cockpit enterprise digital system or iPad tablet. Computer widescreens are better for diagnosing scanned glass slide that iPad. For urgent requests, iPad may be used. Legal aspects have to be soon faced with to permit the clinical use of this technology in a manner that does not compromise patient care.

Validating whole slide imaging for diagnostic purposes in pathology: guideline from the College of American Pathologists Pathology and Laboratory Quality Center

CONTEXT

There is increasing interest in using whole slide imaging (WSI) for diagnostic purposes (primary and/or consultation). An important consideration is whether WSI can safely replace conventional light microscopy as the method by which pathologists review histologic sections, cytology slides, and/or hematology slides to render diagnoses. Validation of WSI is crucial to ensure that diagnostic performance based on digitized slides is at least equivalent to that of glass slides and light microscopy. Currently, there are no standard guidelines regarding validation of WSI for diagnostic use.

OBJECTIVE

To recommend validation requirements for WSI systems to be used for diagnostic purposes.

DESIGN

The College of American Pathologists Pathology and Laboratory Quality Center convened a nonvendor panel from North America with expertise in digital pathology to develop these validation recommendations. A literature review was performed in which 767 international publications that met search term requirements were identified. Studies outside the scope of this effort and those related solely to technical elements, education, and image analysis were excluded. A total of 27 publications were graded and underwent data extraction for evidence evaluation. Recommendations were derived from the strength of evidence determined from 23 of these published studies, open comment feedback, and expert panel consensus.

RESULTS

Twelve guideline statements were established to help pathology laboratories validate their own WSI systems intended for clinical use. Validation of the entire WSI system, involving pathologists trained to use the system, should be performed in a manner that emulates the laboratory's actual clinical environment. It is recommended that such a validation study include at least 60 routine cases per application, comparing intraobserver diagnostic concordance between digitized and glass slides viewed at least 2 weeks apart. It is important that the validation process confirm that all material present on a glass slide to be scanned is included in the digital image.

CONCLUSIONS

Validation should demonstrate that the WSI system under review produces acceptable digital slides for diagnostic interpretation. The intention of validating WSI systems is to permit the clinical use of this technology in a manner that does not compromise patient care.

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.

Republished: going glass to digital: virtual microscopy as a simulation-based revolution in pathology and laboratory science

The recent technological advance of digital high resolution imaging has allowed the field of pathology and medical laboratory science to undergo a dramatic transformation with the incorporation of virtual microscopy as a simulation-based educational and diagnostic tool. This transformation has correlated with an overall increase in the use of simulation in medicine in an effort to address dwindling clinical resource availability and patient safety issues currently facing the modern healthcare system. Virtual microscopy represents one such simulation-based technology that has the potential to enhance student learning and readiness to practice while revolutionising the ability to clinically diagnose pathology collaboratively across the world. While understanding that a substantial amount of literature already exists on virtual microscopy, much more research is still required to elucidate the full capabilities of this technology. This review explores the use of virtual microscopy in medical education and disease diagnosis with a unique focus on key requirements needed to take this technology to the next level in its use in medical education and clinical practice.

Development of a teledermatopathology consultation system using virtual slides

Background

An online consultation system using virtual slides (whole slide images; WSI) has been developed for pathological diagnosis, and could help compensate for the shortage of pathologists, especially in the field of dermatopathology and in other fields dealing with difficult cases. This study focused on the performance and future potential of the system.

Method

In our system, histological specimens on slide glasses are digitalized by a virtual slide instrument, converted into web data, and up-loaded to an open server. Using our own purpose-built online system, we then input patient details such as age, gender, affected region, clinical data, past history and other related items. We next select up to ten consultants. Finally we send an e-mail to all consultants simultaneously through a single command. The consultant receives an e-mail containing an ID and password which is used to access the open server and inspect the images and other data associated with the case. The consultant makes a diagnosis, which is sent to us along with comments.

Because this was a pilot study, we also conducted several questionnaires with consultants concerning the quality of images, operability, usability, and other issues.

Results

We solicited consultations for 36 cases, including cases of tumor, and involving one to eight consultants in the field of dermatopathology. No problems were noted concerning the images or the functioning of the system on the sender or receiver sides. The quickest diagnosis was received only 18 minutes after sending our data. This is much faster than in conventional consultation using glass slides. There were no major problems relating to the diagnosis, although there were some minor differences of opinion between consultants. The results of questionnaires answered by many consultants confirmed the usability of this system for pathological consultation. (16 out of 23 consultants.)

Conclusion

We have developed a novel teledermatopathological consultation system using virtual slides, and investigated the usefulness of the system. The results demonstrate that our system can be a useful tool for international medical work, and we anticipate its wider application in the future.

Virtual slides

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1902376044831574

Digital slide images for primary diagnostics in breast pathology: a feasibility study

Digital slide images have been used in many areas of pathology such as teaching, research, digital archiving, teleconsultation, and quality assurance testing. However, they have not much been used as yet for upfront diagnostics. The aim of this study was therefore to test the feasibility of digital slide image-based diagnosis of breast specimens. Sections of 100 breast specimens previously diagnosed conventionally were scanned and rediagnosed on digital slide images by the same pathologists who performed the initial light microscopy-based diagnosis. The digital slide image diagnoses were compared with the light microscopy diagnoses and classified as concordant, slightly discrepant (without clinical or prognostic consequences), or discrepant. The original light microscopy- and digital slide image-based diagnoses were concordant in 93% and slightly discrepant in 6% of cases. There was only 1 discrepant case with clinical or prognostic implication to the patient. However, for this case, no final agreement could be achieved. For 4 of the 6 slightly discrepant cases, digital slide image diagnosis was considered the better one, whereas the original diagnosis was preferred in only 1 case. In addition, for 1 case categorized as slightly discrepant, both the digital slide image and conventional diagnosis were imperfect according to 2 reviewing breast pathologists. This study demonstrates that upfront histopathologic diagnosis of breast biopsies and resections can reliably be done on digital slide image.

Whole-slide imaging: routine pathologic diagnosis

Digital pathology systems offer pathologists an alternate, emerging mechanism to manage and interpret information. They offer increasingly fast and scalable hardware platforms for slide scanning and software that facilitates remote viewing, slide conferencing, archiving, and image analysis. Deployed initially and validated largely within the research and biopharmaceutical industries, WSI is increasingly being implemented for direct patient care. Improvements in image quality, scan times, and imageviewing browsers will hopefully allow pathologists to more seamlessly convert to digital pathology, much like our radiology colleagues have done before us. However, WSI creates both opportunities and challenges. Although niche applications of WSI technology for clinical, educational, and research purposes are clearly successful, it is evident that several areas still require attention and careful consideration before more widespread clinical adoption of WSI takes place. These include regulatory issues, development of standards of practice and validation guidelines, workflow modifications, as well as defining situations where WSI technology will really improve practice in a cost-effective way. Current progress on these and other issues, along with improving technology, will no doubt pave the way for increased adoption over the next decade, allowing the pathology community as a whole to harness the true potential of WSI for patient care. The digital decade will likely redefine how pathology is practiced and the role of the pathologist.

Introduction of virtual microscopy in routine surgical pathology--a hypothesis and personal view from Europe

The technology of whole image acquisition from histological glass slides (Virtual slides, (VS)) and its associated software such as image storage, viewers, and virtual microscopy (VM), has matured in the recent years. There is an ongoing discussion whether to introduce VM into routine diagnostic surgical pathology (tissue-based diagnosis) or not, and if these are to be introduced how best to do this. The discussion also centres around how to substantially define the mandatory standards and working conditions related to introducing VM. This article briefly describes some hypotheses alongside our perspective and that of several of our European colleagues who have experienced VS and VM either in research or routine praxis. After consideration of the different opinions and published data the following statements can be derived: 1. Experiences from static and remote telepathology as well as from daily routine diagnoses, confirm that VM is a diagnostic tool that can be handled with the same diagnostic accuracy as conventional microscopy; at least no statistically significant differences (p > 0.05) exist. 2. VM possesses several practical advantages in comparison to conventional microscopy; such as digital image storage and retrieval and contemporary display of multiple images (acquired from different stains, and/or different cases). 3. VM enables fast and efficient feedback between the pathologist and the laboratory in terms of ordered additional stains, automated access to the latest research for references, and fast consultation with outstanding telepathology experts. 4. Industry has already invested “big money” into this technology which certainly will be of influence in its future development. The main constraints against VM include the questionable reimbursement of the initial investment, the missing direct and short term financial benefit, and the loss of potential biological identity between the patient and the examined tissue. This article tries to analyze and evaluate the factors that influence the implementation of VM into routine tissue-based diagnosis, for example in combination with predictive diagnosis. It focuses on describing the advantages of modern and innovative electronically based communication technology.

Virtual microscopy using whole-slide imaging as an enabler for teledermatopathology: A paired consultant validation study

Background:

There is a need for telemedicine, particularly in countries with large geographical areas and widely scattered low-density communities as is the case of the Canadian system, particularly if equality of care is to be achieved or the difference gap is to be narrowed between urban centers and more peripheral communities.

Aims:

1. To validate teledermatopathology as a diagnostic tool in under-serviced areas; 2. To test its utilization in inflammatory and melanocytic lesions; 3. To compare the impact of 20× (0.5 μm/pixel) and 40× (0.25 μm/pixel) scans on the diagnostic accuracy.

Materials and Methods:

A total of 103 dermatopathology cases divided into three arms were evaluated by two pathologists and results compared. The first arm consisted of 79 consecutive routine cases (n=79). The second arm consisted of 12 inflammatory skin biopsies (n=12) and the third arm consisted of 12 melanocytic lesions (n=12). Diagnosis concordance was used to evaluate the first arm. Whereas concordance of preset objective findings were used to evaluate the second and third arms.

Results:

The diagnostic concordance rate for the first arm was 96%. The concordance rates of the objective findings for the second and third arms were 100%. The image quality was deemed superior to light microscopy for 40× scans.

Conclusion:

The current scanners produce high-resolution images that are adequate for evaluation of a variety of cases of different complexities.

Virtual slides in peer reviewed, open access medical publication

Background

Application of virtual slides (VS), the digitalization of complete glass slides, is in its infancy to be implemented in routine diagnostic surgical pathology and to issues that are related to tissue-based diagnosis, such as education and scientific publication.

Approach

Electronic publication in Pathology offers new features of scientific communication in pathology that cannot be obtained by conventional paper based journals. Most of these features are based upon completely open or partly directed interaction between the reader and the system that distributes the article. One of these interactions can be applied to microscopic images allowing the reader to navigate and magnify the presented images. VS and interactive Virtual Microscopy (VM) are a tool to increase the scientific value of microscopic images.

Technology and Performance

The open access journal Diagnostic Pathology http://www.diagnosticpathology.org has existed for about five years. It is a peer reviewed journal that publishes all types of scientific contributions, including original scientific work, case reports and review articles. In addition to digitized still images the authors of appropriate articles are requested to submit the underlying glass slides to an institution (DiagnomX.eu, and Leica.com) for digitalization and documentation. The images are stored in a separate image data bank which is adequately linked to the article. The normal review process is not involved. Both processes (peer review and VS acquisition) are performed contemporaneously in order to minimize a potential publication delay. VS are not provided with a DOI index (digital object identifier). The first articles that include VS were published in March 2011.

Results and Perspectives

Several logistic constraints had to be overcome until the first articles including VS could be published. Step by step an automated acquisition and distribution system had to be implemented to the corresponding article. The acceptance of VS by the reader is high as well as by the authors. Of specific value are the increased confidence to and reputation of authors as well as the presented information to the reader. Additional associated functions such as access to author-owned related image collections, reader-controlled automated image measurements and image transformations are in preparation.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1232133347629819.

Innovative Methods of Archiving, Presentation and Providing Access to Histological Sections

The dynamic development of technical sciences and informatics makes now possible acquisition of microscopic images of histological sections, not only using digital cameras, but also through specialized devices called scanners. The digitalized images stored in a computer storage device are called virtual slides and, together with special software, are known as virtual microscopy. The virtual slides can be analyzed on a computer screen by panoramic viewing or using a detailed image examination at higher magnification. In many research and education institutions in both the U.S. and Europe, the virtual microscopy is used for teaching and training purposes. In the academic year of 2009/10, Department of Histology and Embryology, University of Medical Sciences in Poznan, as one of the first in Poland, has created a virtual database for educational purposes. This database created by archiving the traditional images of histological slides in the form of digital images. So far, more than 130 virtual slides have been acquired and catalogued in 24 thematic folders, available for medical students participating in histology, embryology and cell biology courses.

Telepathology is the second branch which uses virtual microscopy. Virtual microscope allows to discuss and resolve medical/diagnostic problems with the use of telecommunication systems and information technology. The existing internet platforms offer access to virtual microscopes and virtual slides. In June, 2011 the Center of Morphologic Images Archivization and Digital Database of Microscopic Pictures in the Department of Histology and Embryology, Poznan University of Medical Sciences has launched an online platform (www.caom.pl), aimed to provide the central database of scanned histological sections of physiological tissues, and pathological, rare and sporadic lesions, including tumor

Computerized texture analysis of atypical immature myeloid precursors in patients with myelodysplastic syndromes: an entity between blasts and promyelocytes

BACKGROUND

Bone marrow (BM) blast count is an essential parameter for classification and prognosis of myelodysplastic syndromes (MDS). However, a high degree of cell atypias in bone marrow hemopoietic cells may be found in this group of clonal disorders, making it difficult to quantify precisely myeloblasts, and to distinguish them from promyelocytes and atypical immature myeloid precursors. Our aim was to investigate whether computerized image analysis of routine cytology would help to characterize these cells.

METHODS

In May-Grünwald-Giemsa stained BM smears of 30 newly diagnosed MDS patients and 19 cases of normal BM, nuclei of blasts and promyelocytes were digitalized and interactively segmented. The morphological classification of the cells was done by consensus of two observers. Immature granulocytic precursors, which could not be clearly classified either as blasts or promyelocytes, were called "atypic myeloid precursors". Nuclear morphometry and texture features derived from the co-occurrence matrix and fractal dimension (FD) were calculated.

RESULTS

In normal BM, when compared to myeloblasts, nuclei of promyelocytes showed significant increase in perimeter and local texture homogeneity and a decrease in form factor, chromatin gray levels, Haralick's entropy, inertia, energy, contrast, diagonal moment, cluster prominence, the fractal dimension according to Minkowski and its goodness-of-fit. Compared to normal myeloblast nuclei, the chromatin texture of MDS myeloblasts revealed higher local homogeneity and goodness-of-fit of the FD, but lower values of entropy, contrast, diagonal moment, and fractal dimension. The same differences were found between nuclei of normal promyelocytes and those of MDS. Nuclei of atypical myeloid precursors showed intermediate characteristics between those of blasts and promyelocytes according to the quantitative features (perimeter, form factor, gray level and its standard deviation), but were similar to promyelocytes according to the texture variables inertia, energy, contrast, diagonal moment, cluster prominence, and Minkowski's fractal dimension.

CONCLUSION

BM atypical immature myeloid precursors are difficult to be correctly classified in routine cytology. Although their cytoplasm is more similar to that of myeloblasts, computerized texture analysis indicates a nuclear chromatin remodeling more close to the promyelocyte, thus indicating an asynchronous intermediate maturation stage between blast and promyelocyte.

Whole slide images for primary diagnostics of gastrointestinal tract pathology: a feasibility study

During the last decade, whole slide images have been used in many areas of pathology such as teaching, research, digital archiving, teleconsultation, and quality assurance testing. However, whole slide images have as yet not much been used for up-front diagnostics because of the lack of validation studies. The aim of this study was, therefore, to test the feasibility of whole slide images for diagnosis of gastrointestinal tract specimens, one of the largest areas of diagnostic pathology. One hundred gastrointestinal tract biopsies and resections that had been diagnosed using light microscopy 1 year before were rediagnosed on whole slide images scanned at ×20 magnification by 5 pathologists (all reassessing their own cases), having the original clinical information available but blinded to their original light microscopy diagnoses. The original light microscopy and whole slide image-based diagnoses were compared and classified as concordant, slightly discordant (without clinical consequences), and discordant. The diagnoses based on light microscopy and the whole slide image-based rediagnoses were concordant in 95% of the cases. Light microscopy and whole slide image diagnosis in the remaining 5% of cases were slightly discordant, none of these were with clinical or prognostic implications. Up-front histopathologic diagnosis of gastrointestinal biopsies and resections can be done on whole slide images.

Web-based database for the management of tissue specimens in a transregional histological research facility

Background

In the setting of a histological research core facility sample tracking and project specific archiving of tissue specimens and communication of related data is of central importance.

Description

Over a 24-month period 10 laboratories from two transregional research centers submitted in excess of 3000 tissue samples for histological processing and evaluation to our core facility. A web based database was set up to overcome the logistical problem of managing samples with inconsistent, duplicate and missing labels and to allow for efficient sample tracking, archiving and communication with the collaborating research laboratories. The database allows the users to remotely generate unique sample identifiers and enter sample annotation prior to sample processing. Furthermore the database facilitates communication about experimental set-up results and media files such as histological images.

Conclusion

Our newly constructed web based portal is an important tool for the management of research samples of our histological core facility and facilitates significantly interdisciplinary and transregional research. It is freely available for scientific use.

Quantification of virtual slides: Approaches to analysis of content-based image information

Virtual microscopy, which is the diagnostic work on completely digitized histological and cytological slides as well as blood smears, is at the stage to be implemented in routine diagnostic surgical pathology (tissue-based diagnosis) in the near future, once it has been accepted by the US Food and Drug Administration. The principle of content-based image information, its mandatory prerequisites to obtain reproducible and stable image information as well as the different compartments that contribute to image information are described in detail. Automated extraction of content-based image information requires shading correction, constant maximum of grey values, and standardized grey value histograms. The different compartments to evaluate image information include objects, structure, and texture. Identification of objects and derived structure depend on segmentation accuracy and applied procedures; textures contain pixel-based image information only. All together, these image compartments posses the discrimination power to distinguish between object space and background, and, in addition, to reproducibly define regions of interest (ROIs). ROIs are image areas which display the information that is of preferable interest to the viewing pathologist. They contribute to the derived diagnosis to a higher level when compared with other image areas. The implementation of content-based image information algorithms to be applied for predictive tissue-based diagnoses is described in detail.

Digital pathology: exploring its applications in diagnostic surgical pathology practice

There has been a recent upsurge in worldwide attention on digital pathology, which has transformed from static snapshots from camera-equipped microscopes to its modern form that encompasses scanning of whole glass slides with evaluation of histological images on a computer screen, along with management of its accompanying information. Although it has been widely accepted in education and research, its implementation in diagnostic surgical pathology practice is not without challenges in workflow integration, technological infrastructure, pathologist acclimatisation, global standardisation for clinical practice, and cost issues, among others. Nonetheless, early adopters have harnessed its benefits in specific niches, like frozen section services and remote second opinion consultations. Its tremendous potential is worthy of further validation to compare with conventional glass slide evaluation, even while it is already paving the way for advancement into virtual three-dimensional imaging technology, with a glimpse into a possible future digital diagnostic pathology practice.

An experimental study of pathologist's navigation patterns in virtual microscopy

In virtual microscopy, a sequential process of captures of microscopical fields, allows to construct a virtual slide which is visualized using a specialized software, called the virtual microscopy viewer. This tool allows useful exploration of images, composed of thousands of microscopical fields of view at different levels of magnification, emulating an actual microscopical examination. The aim of this study was to establish the main pathologist's navigation patterns when exploring virtual microscopy slides, using a graphical user interface, adapted to the pathologist's workflow. Four pathologists with a similar level of experience, graduated from the same pathology program, navigated six virtual slides. Different issues were evaluated, namely, the percentage of common visited image regions, the time spent at each and its coincidence level, that is to say, the region of interest location. In addition, navigation patterns were also assessed, i.e., mouse movement velocities and linearity of the diagnostic paths. Results suggest that regions of interest are determined by a complex combination of the visited area, the time spent at each visit and the coincidence level among pathologists. Additionally, linear trajectories and particular velocity patterns were found for the registered diagnostic paths.

A soft-cache strategy for pathologist's navigation in virtual microscopy

Navigation through large microscopical images demands special characteristics like flexibility to access image data and progressive recovery or relevant information, i.e., several qualities, magnifications, and random accesses to any desired Window of Interest in the Virtual Slide (VS). Nowadays there exist systems that allow such interaction, but with a certain delay, which is dependent on the application. It has been shown that caching or prefetching policies can speed up interaction with these systems. This article presents an optimal soft-cache strategy, which improves the navigation times in virtual microscopy. The entire method includes an optimal soft-cache strategy and a dynamical probabilistic model of a pathologist's navigation. This strategy was implemented as a Client-Server application, using the JPEG2000-JPIP standard and evaluated using different navigation patterns, namely, four different pathologists exploring 10 VS, stained with different dyes. The present approach was compared with a conventional soft-cache method and the cache performance improved, in average, in about a 10%.

Telepathology for patient care: what am I getting myself into?

The vast advancements in telecommunications and converting medical information to a digital format have increased the number of applications within telemedicine. Telepathology, in simplest terms, is the practice of formally rendering a pathologic diagnosis based upon examination of an image rather than of a glass slide through traditional microscopy. The use of telepathology for clinical patient care has so far been limited to relatively few large academic institutions. Although a number of challenges remain, there is increasing demand for the use of information technology in pathology as a whole owing to the expansion of health care networks and the opportunity to enhance the quality of service delivered to patients. The software used to acquire, display, and manage digital images for clinical patient care may be subject to national and federal regulations just as is any other electronic information system. Despite the barriers, telepathology systems possess the capability to help manage pathology cases on a global scale, improve laboratory workload distribution, increase standardization of practice and enable new classes of ancillary studies to facilitate diagnosis and education even in the most remote parts of the earth.

Creation of a fully digital pathology slide archive by high-volume tissue slide scanning

Digital slide scanners for scanning glass slides are becoming increasingly popular because current scanners are fast enough and produce good enough images for diagnostic purposes, education, and research. Also, the price for storing vast amounts of data has decreased over the last years, and this trend is expected to continue. Where most laboratories use their scanners mainly for education and research with limited financial and technical implications, we decided to face the huge challenges of prospectively setting up a fully digital pathology slide archive, primarily aiming to optimize the preparation and running of clinicopathological conferences. In this article, we describe the setup of our digital archiving solution and discuss the technical challenges we had to overcome. To give insight in the performance of our digital archive, we provide some statistics as well. We also present our thoughts on future developments in the area of digital slide scanning.