Competence on demand in DNA image cytometry

DNA image cytometry for diagnosis of early gastric cancer

Gastric cancer (GC) is one of the most common malignant tumors, with high morbidity and mortality. Early detection, diagnosis and treatment are the key to improve the curative effect and prolong the survival of the patients. At present, tumor cell DNA detection technology has been used for the assistant diagnosis of a variety of common tumors and can improve the early detection rate of benign and malignant tumors. In the process of malignant transformation of cells, changes in genetic material such as DNA are earlier than the morphological changes of cells. Therefore, the DNA image cytometry of cells can be used to find early malignant cells with genetic material abnormalities. Being able to detect GC earlier, DNA image cytometry can increase the detection rate of early GC and improve the treatment and prognosis of patients.This article reviews the application of DNA image cytometry in the diagnosis of early GC.

Adaptation of image cytometry methodology for DNA ploidy analysis of cervical epithelium samples: a pilot study

OBJECTIVE

To determine DNA ploidy in the cervical specimens of patients revealing a suspicion of cancer by image analysis performed by using a combination of commercial analysis software, conventional microscopy, and certified filters.

MATERIALS AND METHODS

This study followed a prospective design. Cervical samples were obtained from 20 patients undergoing routine screening in the Gynecologic-Oncology Unit of the University Hospital of the Federal University of Minas Gerais, Brazil. Three slides were prepared for each case and the DNA content was determined by image cytometry, post Feulgen staining. DNA ploidy, as well as events exceeding 5C and 9C, was assessed according to the guidelines and algorithms prescribed for diagnostic interpretation by the European Society for Analytical Cellular Pathology.

RESULTS

By employing the adapted tool, identification of the lesions with euploid and aneuploid profiles was possible. Abnormal DNA content was found in 65% of the cases (13/20), with 45% (9/20) presenting nuclei with >5C content and 20% (4/20) with >9C content. In the analyses conducted in this study, the coefficient of variation with respect to DNA quantity was lower than the 5% threshold recommended by the European Society for Analytical Cellular Pathology.

CONCLUSION

Image cytometry of the cervical specimens revealed DNA aneuploidy, most probably resulting from chromosomal alterations and appearing as precancerous lesions in 65% of the cases. The adaptations implemented in this study, enabled the DNA-image cytometry to become more accessible, enhancing its extended use as an adjuvant strategy for the early screening of the cervical epithelium samples during routine analyses.

Quantitative pathology in virtual microscopy: history, applications, perspectives

With the emerging success of commercially available personal computers and the rapid progress in the development of information technologies, morphometric analyses of static histological images have been introduced to improve our understanding of the biology of diseases such as cancer. First applications have been quantifications of immunohistochemical expression patterns. In addition to object counting and feature extraction, laws of thermodynamics have been applied in morphometric calculations termed syntactic structure analysis. Here, one has to consider that the information of an image can be calculated for separate hierarchical layers such as single pixels, cluster of pixels, segmented small objects, clusters of small objects, objects of higher order composed of several small objects. Using syntactic structure analysis in histological images, functional states can be extracted and efficiency of labor in tissues can be quantified. Image standardization procedures, such as shading correction and color normalization, can overcome artifacts blurring clear thresholds. Morphometric techniques are not only useful to learn more about biological features of growth patterns, they can also be helpful in routine diagnostic pathology. In such cases, entropy calculations are applied in analogy to theoretical considerations concerning information content. Thus, regions with high information content can automatically be highlighted. Analysis of the "regions of high diagnostic value" can deliver in the context of clinical information, site of involvement and patient data (e.g. age, sex), support in histopathological differential diagnoses. It can be expected that quantitative virtual microscopy will open new possibilities for automated histological support. Automated integrated quantification of histological slides also serves for quality assurance. The development and theoretical background of morphometric analyses in histopathology are reviewed, as well as their application and potential future implementation in virtual microscopy.

The history of pathology informatics: A global perspective

Pathology informatics has evolved to varying levels around the world. The history of pathology informatics in different countries is a tale with many dimensions. At first glance, it is the familiar story of individuals solving problems that arise in their clinical practice to enhance efficiency, better manage (e.g., digitize) laboratory information, as well as exploit emerging information technologies. Under the surface, however, lie powerful resource, regulatory, and societal forces that helped shape our discipline into what it is today. In this monograph, for the first time in the history of our discipline, we collectively perform a global review of the field of pathology informatics. In doing so, we illustrate how general far-reaching trends such as the advent of computers, the Internet and digital imaging have affected pathology informatics in the world at large. Major drivers in the field included the need for pathologists to comply with national standards for health information technology and telepathology applications to meet the scarcity of pathology services and trained people in certain countries. Following trials by a multitude of investigators, not all of them successful, it is apparent that innovation alone did not assure the success of many informatics tools and solutions. Common, ongoing barriers to the widespread adoption of informatics devices include poor information technology infrastructure in undeveloped areas, the cost of technology, and regulatory issues. This review offers a deeper understanding of how pathology informatics historically developed and provides insights into what the promising future might hold.

Diagnostic and prognostic significance of image cytometric DNA ploidy measurement in cytological samples of cervical squamous intraepithelial lesions

OBJECTIVE

To study the DNA ploidy pattern of uterine cervical squamous intraepithelial lesions (SILs) and its diagnostic and prognostic significance.

METHODS

The study included 31 cases of SIL: 11 low-grade (LSIL) and 20 high-grade (HSIL). Feulgen-pararosaniline staining was performed on previously Papanicolaou-stained smears and a DNA image cytometric study was performed. An internal reference was used to calibrate the samples.

RESULTS

All 31 cases of SIL, either LSIL or HSIL, were non-diploid. Of the 11 cases of LSIL, four were tetraploid and seven were aneuploid, whereas, of the 20 cases of HSIL, four were tetraploid and 16 were aneuploid. Stemline aneuploidy was not a significant discriminator between LSIL and HSIL (P=0.32). Based on single-cell analysis, HSIL cases had significantly higher DNA content than LSIL cases (P<0.01). When a mean of 30% or more was used for the 6c-exceeding event (6cEE) value, the sensitivity and specificity to indicate HSIL were 83% and 64%, respectively, with a positive predictive value (PPV) of 81% and negative predictive value (NPV) of 65%. All HSIL cases were cervical intraepithelial neoplasia grade 2 or worse (CIN2+) on biopsy. In addition, cases which showed recurrence had more DNA content by single-cell analysis than those with an indolent clinical behaviour: P=0.04 and P=0.03 for LSIL and HSIL, respectively.

CONCLUSIONS

Image cytometric DNA analysis is a useful technique for diagnostic and prognostic purposes in uterine cervical SIL when appropriate 'c' values are used in single-cell analysis. We propose that a >6c DNA content of 30% is useful as a cut-off level for predicting cases with CIN2+ in DNA image cytometry of cervical smears.

Image processing methods and architectures in diagnostic pathology

Grid technology has enabled the clustering and the efficient and secure access to and interaction among a wide variety of geographically distributed resources such as: supercomputers, storage systems, data sources, instruments and special devices and services. Their main applications include large-scale computational and data intensive problems in science and engineering. General grid structures and methodologies for both software and hardware in image analysis for virtual tissue-based diagnosis has been considered in this paper. This methods are focus on the user level middleware. The article describes the distributed programming system developed by the authors for virtual slide analysis in diagnostic pathology. The system supports different image analysis operations commonly done in anatomical pathology and it takes into account secured aspects and specialized infrastructures with high level services designed to meet application requirements. Grids are likely to have a deep impact on health related applications, and therefore they seem to be suitable for tissue-based diagnosis too. The implemented system is a joint application that mixes both Web and Grid Service Architecture around a distributed architecture for image processing. It has shown to be a successful solution to analyze a big and heterogeneous group of histological images under architecture of massively parallel processors using message passing and non-shared memory.

Toward a multimodal cell analysis of brush biopsies for the early detection of oral cancer

BACKGROUND

This report describes what to the authors' knowledge is the first clinical application of semiautomated multimodal cell analysis (MMCA), a novel technique for the early detection of cancer for cases with a limited number of suspicious cells. In this clinical study, MMCA was applied to oral cancer diagnostics on brush biopsies. The MMCA approach was based on the sequential application of multiple stainings of identical, slide-based cells and repeated relocalizations and measurements of their diagnostic features, resulting in multiparametric features of individual cells. Data integration of the variously stained cells increased diagnostic accuracy. The implementation of MMCA also enabled fully automatic, adaptive image preprocessing, including registration of multimodal images and segmentation of cell nuclei.

METHODS

In a preliminary clinical trial, 47 slides from brush biopsies of suspicious oral lesions were analyzed. The final histologic diagnoses included 20 squamous cell carcinomas, 7 hyperkeratotic leukoplakias, and 20 lichen planus mucosae.

RESULTS

The stepwise application of 2 additional approaches (morphology, DNA content, argyrophilic nucleolar organizer region counts) increased the specificity of conventional cytologic diagnosis from 92.6% to 100%. This feasibility study provided a proof of concept, demonstrating efficiency, robustness, and diagnostic accuracy on slide-based cytologic specimens.

CONCLUSIONS

The authors concluded that MMCA may become a sensitive and highly specific, objective, and reproducible adjuvant diagnostic tool for the identification of neoplastic changes in oral smears that contain only a few abnormal cells.

Image standards in tissue-based diagnosis (diagnostic surgical pathology)

Background

Progress in automated image analysis, virtual microscopy, hospital information systems, and interdisciplinary data exchange require image standards to be applied in tissue-based diagnosis.

Aims

To describe the theoretical background, practical experiences and comparable solutions in other medical fields to promote image standards applicable for diagnostic pathology.

Theory and experiences

Images used in tissue-based diagnosis present with pathology – specific characteristics. It seems appropriate to discuss their characteristics and potential standardization in relation to the levels of hierarchy in which they appear. All levels can be divided into legal, medical, and technological properties. Standards applied to the first level include regulations or aims to be fulfilled. In legal properties, they have to regulate features of privacy, image documentation, transmission, and presentation; in medical properties, features of disease – image combination, human – diagnostics, automated information extraction, archive retrieval and access; and in technological properties features of image acquisition, display, formats, transfer speed, safety, and system dynamics. The next lower second level has to implement the prescriptions of the upper one, i.e. describe how they are implemented. Legal aspects should demand secure encryption for privacy of all patient related data, image archives that include all images used for diagnostics for a period of 10 years at minimum, accurate annotations of dates and viewing, and precise hardware and software information. Medical aspects should demand standardized patients' files such as DICOM 3 or HL 7 including history and previous examinations, information of image display hardware and software, of image resolution and fields of view, of relation between sizes of biological objects and image sizes, and of access to archives and retrieval. Technological aspects should deal with image acquisition systems (resolution, colour temperature, focus, brightness, and quality evaluation procedures), display resolution data, implemented image formats, storage, cycle frequency, backup procedures, operation system, and external system accessibility. The lowest third level describes the permitted limits and threshold in detail. At present, an applicable standard including all mentioned features does not exist to our knowledge; some aspects can be taken from radiological standards (PACS, DICOM 3); others require specific solutions or are not covered yet.

Conclusion

The progress in virtual microscopy and application of artificial intelligence (AI) in tissue-based diagnosis demands fast preparation and implementation of an internationally acceptable standard. The described hierarchic order as well as analytic investigation in all potentially necessary aspects and details offers an appropriate tool to specifically determine standardized requirements.

How to implement grid technology in tissue-based diagnosis: diagnostic surgical pathology

BACKGROUND

Tissue-based diagnosis or diagnostic surgical pathology is a highly accurate, sensitive and specific medical diagnostic technique that has expanded rapidly in using both molecular biology and computer technology.

OBJECTIVE

The objective is to analyze the present stage and potential influence of distributed data acquisition, analysis and presentation in tissue-based diagnosis by using recently developed standardized network systems such as grids.

METHODS

Interpretation of medical data is often based upon specialized examination, visual information acquisition and transfer as well as upon data collected from various sources. Efficient and accurate diagnostics require standardized data and transfer modes, which can be provided by a grid environment. The medical requirements, construction of an adequate grid environment, practical experiences in various medical disciplines and potential use in tissue-based diagnosis are described.

CONCLUSIONS

Grid technology is probably a useful tool to meet the conditions of tissue-based diagnosis in the near future, and will probably play a significant role in its further development.

Grid technology in tissue-based diagnosis: fundamentals and potential developments

Tissue-based diagnosis still remains the most reliable and specific diagnostic medical procedure. It is involved in all technological developments in medicine and biology and incorporates tools of quite different applications. These range from molecular genetics to image acquisition and recognition algorithms (for image analysis), or from tissue culture to electronic communication services. Grid technology seems to possess all features to efficiently target specific constellations of an individual patient in order to obtain a detailed and accurate diagnosis in providing all relevant information and references. Grid technology can be briefly explained by so-called nodes that are linked together and share certain communication rules in using open standards. The number of nodes can vary as well as their functionality, depending on the needs of a specific user at a given point in time. In the beginning of grid technology, the nodes were used as supercomputers in combining and enhancing the computation power. At present, at least five different Grid functions can be distinguished, that comprise 1) computation services, 2) data services, 3) application services, 4) information services, and 5) knowledge services. The general structures and functions of a Grid are described, and their potential implementation into virtual tissue-based diagnosis is analyzed. As a result Grid technology offers a new dimension to access distributed information and knowledge and to improving the quality in tissue-based diagnosis and therefore improving the medical quality.

Diagnostic and prognostic use of DNA image cytometry in cervical squamous intraepithelial lesions and invasive carcinoma

In the fight against cervical malignancy and its precursors, several adjuvant diagnostic methods have been proposed to increase the accuracy of cytologic and histologic diagnoses. Because chromosomal aneuploidy has been accepted as an early key event in tumorigenesis caused by genetic instability, the cytometric equivalent of chromosomal aneuploidy detected by DNA image cytometry (DNA-ICM) may serve as a marker of neoplasia. During the last decade, the appearance of a new generation of hardware with high processing and storage capacities, together with the development of appropriate software, has facilitated the development of high-performance DNA-ICM systems. International consensus on the clinical application of DNA-ICM has been reached. According to the statements of Task Force 8 of the International Consensus Conference on the Fight Against Cervical Cancer, indications for DNA-ICM include the identification of prospectively malignant cells in squamous intraepithelial lesions (SILs) and atypical squamous cells of undetermined significance (ASCUS). The European Society of Analytical Cellular Pathology consensus reports on DNA-ICM have provided standardized technical details on performance, terms, and algorithms for diagnostic data interpretation and quality-assurance procedures. Increasing biologic evidence and clinical data have confirmed the utility of DNA-ICM as an adjuvant method suitable for determining the diagnosis and prognosis of cervical intraepithelial lesions and invasive carcinoma. Patients with ASCUS and low-grade SIL diagnoses that reveal DNA euploidy may return for normal screening intervals, whereas the detection of DNA aneuploidy indicates that these lesions should be removed. Formerly a research tool, today, standardized DNA-ICM has become a useful and low-cost laboratory method to establish objectively and reproducibly an early diagnosis of prospectively progressive cervical intraepithelial lesions at a high-quality level. DNA-ICM may further contribute to the monitoring of treatment in patients with invasive cervical malignancies.

[Atopic keratoconjunctivitis: probably a risk factor for the development of conjuntival carcinoma]

BACKGROUND

Almost half of the patients with atopic dermatitis experience chronic inflammation of the eyelids, the conjunctiva and the cornea. Chronic inflammation is a possible cause for the development of malignancies, especially if associated with some kind of immunological defect as in atopic patients. So far, a correlation between atopic conjunctivitis and conjunctival malignancies has not yet been reported. Here, we present 7 atopic patients with conjunctival carcinoma or carcinoma in situ detected between February 2000 and August 2001.

PATIENTS

All 7 patients had a long history of atopic dermatitis and chronic of inflammation of the conjunctiva and cornea. In all patients smears were examined by cytology and DNA cytometry. Furthermore, in 6 of the 7 patients a histopathological examination of conjunctival biopsies was performed.

RESULTS

In 4 of the 7 patients invasive conjunctival carcinoma and in 2 carcinoma in situ were detected. Cytology and cytometry revealed conjunctival carcinoma or carcinoma in situ in the remaining patient. Histopathological examination could not be performed since the patient refused to have a conjunctival biopsy.

CONCLUSIONS

These results suggest that atopic keratoconjunctivitis might be a risk factor for the development of conjunctival carcinoma.

Telepathology: current status and future prospects in diagnostic histopathology

Telepathology is the process of diagnostic histopathology performed on digital images viewed on a display screen rather than by conventional glass slide light microscopy. The technology of telepathology has radically improved over the past 5 years so that it is no longer the limiting factor in the diagnostic process. This review looks at the resources needed for dynamic and static telepathology, including image quality, computers and software interfaces, means of transmission and human resources. It critically analyses 32 published trials of telepathology, including some large prospective studies, in all areas of diagnostic histopathology including intraoperative frozen sections, routine and referral cases. New developments, including internet solutions and virtual microscopy, are described and there is analysis of the economics of telepathology within health care systems. The review concludes that all the necessary technology for telepathology is available, there is strong published evidence for a diagnostic accuracy comparable with glass slide diagnosis, in many contexts there is a clear-cut economic argument in favour of telepathology, and that the technique should now be integrated into mainstream diagnostic histopathology.