Review of imaging solutions for integrated quantitative immunohistochemistry in the Pathology daily practice.

Immunohistochemistry (IHC) plays an essential role in Pathology. In order to improve reproducibility and standardization of the results interpretation, IHC quantification methods have been developed. IHC interpretation based in whole slide imaging or virtual microscopy is of special interest. The objective of this work is to review the different computer-based programs for automatic immunohistochemistry and Fluorescence In Situ Hybridization (FISH) evaluation. Scanning solutions and image analysis software in immunohistochemistry were studied, focusing especially on systems based in virtual slides. Integrated scanning and image analysis systems are available (Bacus TMAScore, Dako ACIS III, Genetix Ariol, Aperio Image Analysis, 3DHistech Mirax HistoQuant, Bioimagene Pathiam). Other image analysis software systems (Definiens TissueMap, SlidePath Tissue Image Analysis) can be applied to several virtual slide formats. Fluorescence is the preferred approach in HistoRx AQUA, since it allows for a better compartmentalization of signals. Multispectral imaging using CRi Nuance allows multiple antibodies immunohistochemistry, and different stain unmixing. Most current popular automated image analysis solutions are aimed to brightfield immunohistochemistry, but fluorescence and FISH solutions may become more important in the near future. Automated quantitative tissue microarrays (TMA) analysis is essential to provide high-throughput analysis. Medical informatics standards in images (DICOM) and workflow (IHE) under development will foster the use of image analysis in Pathology Departments

Tissue Phenomics for prognostic biomarker discovery in low- and intermediate-risk prostate cancer

Tissue Phenomics is the discipline of mining tissue images to identify patterns that are related to clinical outcome providing potential prognostic and predictive value. This involves the discovery process from assay development, image analysis, and data mining to the final interpretation and validation of the findings. Importantly, this process is not linear but allows backward steps and optimization loops over multiple sub-processes. We provide a detailed description of the Tissue Phenomics methodology while exemplifying each step on the application of prostate cancer recurrence prediction. In particular, we automatically identified tissue-based biomarkers having significant prognostic value for low-and intermediate-risk prostate cancer patients (Gleason scores 6-7b) after radical prostatectomy. We found that promising phenes were related to CD8(+) and CD68(+) cells in the microenvironment of cancerous glands in combination with the local micro-vascularization. Recurrence prediction based on the selected phenes yielded accuracies up to 83% thereby clearly outperforming prediction based on the Gleason score. Moreover, we compared different machine learning algorithms to combine the most relevant phenes resulting in increased accuracies of 88% for tumor progression prediction. These findings will be of potential use for future prognostic tests for prostate cancer patients and provide a proof-of-principle of the Tissue Phenomics approach

Histopathological image analysis : a review

Over the past decade, dramatic increases in computational power and improvement in image analysis algorithms have allowed the development of powerful computer-assisted analytical approaches to radiological data. With the recent advent of whole slide digital scanners, tissue histopathology slides can now be digitized and stored in digital image form. Consequently, digitized tissue histopathology has now become amenable to the application of computerized image analysis and machine learning techniques. Analogous to the role of computer-assisted diagnosis (CAD) algorithms in medical imaging to complement the opinion of a radiologist, CAD algorithms have begun to be developed for disease detection, diagnosis, and prognosis prediction to complement the opinion of the pathologist. In this paper, we review the recent state of the art CAD technology for digitized histopathology. This paper also briefly describes the development and application of novel image analysis technology for a few specific histopathology related problems being pursued in the United States and Europe

A Method for Unsupervised Semi-Quantification of Inmunohistochemical Staining with Beta Divergences

In many research laboratories, it is essential to determine the relative expression levels of some proteins of interest in tissue samples. The semi-quantitative scoring of a set of images consists of establishing a scale of scores ranging from zero or one to a maximum number set by the researcher and assigning a score to each image that should represent some predefined characteristic of the IHC staining, such as its intensity. However, manual scoring depends on the judgment of an observer and therefore exposes the assessment to a certain level of bias. In this work, we present a fully automatic and unsupervised method for comparative biomarker quantification in histopathological brightfield images. The method relies on a color separation method that discriminates between two chromogens expressed as brown and blue colors robustly, independent of color variation or biomarker expression level. For this purpose, we have adopted a two-stage stain separation approach in the optical density space. First, a preliminary separation is performed using a deconvolution method in which the color vectors of the stains are determined after an eigendecomposition of the data. Then, we adjust the separation using the non-negative matrix factorization method with beta divergences, initializing the algorithm with the matrices resulting from the previous step. After that, a feature vector of each image based on the intensity of the two chromogens is determined. Finally, the images are annotated using a systematically initialized k-means clustering algorithm with beta divergences. The method clearly defines the initial boundaries of the categories, although some flexibility is added. Experiments for the semi-quantitative scoring of images in five categories have been carried out by comparing the results with the scores of four expert researchers yielding accuracies that range between 76.60% and 94.58%. These results show that the proposed automatic scoring system, which is definable and reproducible, produces consistent results.FEDER / Junta de Andalucía-Consejería de Economía y Conocimiento US-1264994Fondo de Desarrollo (FEDER). Unión Europea PGC2018-096244-B-I00, SAF2016-75442-RMinisterio de Economía, Industria y Competitividad (MINECO). España TEC2017- 82807-

A Colour Wheel to Rule them All: Analysing Colour & Geometry in Medical Microscopy

Personalized medicine is a rapidly growing field in healthcare that aims to customize medical treatments and preventive measures based on each patient’s unique characteristics, such as their genes, environment, and lifestyle factors. This approach acknowledges that people with the same medical condition may respond differently to therapies and seeks to optimize patient outcomes while minimizing the risk of adverse effects. To achieve these goals, personalized medicine relies on advanced technologies, such as genomics, proteomics, metabolomics, and medical imaging. Digital histopathology, a crucial aspect of medical imaging, provides clinicians with valuable insights into tissue structure and function at the cellular and molecular levels. By analyzing small tissue samples obtained through minimally invasive techniques, such as biopsy or aspirate, doctors can gather extensive data to evaluate potential diagnoses and clinical decisions. However, digital analysis of histology images presents unique challenges, including the loss of 3D information and stain variability, which is further complicated by sample variability. Limited access to data exacerbates these challenges, making it difficult to develop accurate computational models for research and clinical use in digital histology. Deep learning (DL) algorithms have shown significant potential for improving the accuracy of Computer-Aided Diagnosis (CAD) and personalized treatment models, particularly in medical microscopy. However, factors such as limited generability, lack of interpretability, and bias sometimes hinder their clinical impact. Furthermore, the inherent variability of histology images complicates the development of robust DL methods. Thus, this thesis focuses on developing new tools to address these issues. Our essential objective is to create transparent, accessible, and efficient methods based on classical principles from various disciplines, including histology, medical imaging, mathematics, and art, to tackle microscopy image registration and colour analysis successfully. These methods can contribute significantly to the advancement of personalized medicine, particularly in studying the tumour microenvironment for diagnosis and therapy research. First, we introduce a novel automatic method for colour analysis and non-rigid histology registration, enabling the study of heterogeneity morphology in tumour biopsies. This method achieves accurate tissue cut registration, drastically reducing landmark distance and excellent border overlap. Second, we introduce ABANICCO, a novel colour analysis method that combines geometric analysis, colour theory, fuzzy colour spaces, and multi-label systems for automatically classifying pixels into a set of conventional colour categories. ABANICCO outperforms benchmark methods in accuracy and simplicity. It is computationally straightforward, making it useful in scenarios involving changing objects, limited data, unclear boundaries, or when users lack prior knowledge of the image or colour theory. Moreover, results can be modified to match each particular task. Third, we apply the acquired knowledge to create a novel pipeline of rigid histology registration and ABANICCO colour analysis for the in-depth study of triple-negative breast cancer biopsies. The resulting heterogeneity map and tumour score provide valuable insights into the composition and behaviour of the tumour, informing clinical decision-making and guiding treatment strategies. Finally, we consolidate the developed ideas into an efficient pipeline for tissue reconstruction and multi-modality data integration on Tuberculosis infection data. This enables accurate element distribution analysis to understand better interactions between bacteria, host cells, and the immune system during the course of infection. The methods proposed in this thesis represent a transparent approach to computational pathology, addressing the needs of medical microscopy registration and colour analysis while bridging the gap between clinical practice and computational research. Moreover, our contributions can help develop and train better, more robust DL methods.En una época en la que la medicina personalizada está revolucionando la asistencia sanitaria, cada vez es más importante adaptar los tratamientos y las medidas preventivas a la composición genética, el entorno y el estilo de vida de cada paciente. Mediante el empleo de tecnologías avanzadas, como la genómica, la proteómica, la metabolómica y la imagen médica, la medicina personalizada se esfuerza por racionalizar el tratamiento para mejorar los resultados y reducir los efectos secundarios. La microscopía médica, un aspecto crucial de la medicina personalizada, permite a los médicos recopilar y analizar grandes cantidades de datos a partir de pequeñas muestras de tejido. Esto es especialmente relevante en oncología, donde las terapias contra el cáncer se pueden optimizar en función de la apariencia tisular específica de cada tumor. La patología computacional, un subcampo de la visión por ordenador, trata de crear algoritmos para el análisis digital de biopsias. Sin embargo, antes de que un ordenador pueda analizar imágenes de microscopía médica, hay que seguir varios pasos para conseguir las imágenes de las muestras. La primera etapa consiste en recoger y preparar una muestra de tejido del paciente. Para que esta pueda observarse fácilmente al microscopio, se corta en secciones ultrafinas. Sin embargo, este delicado procedimiento no está exento de dificultades. Los frágiles tejidos pueden distorsionarse, desgarrarse o agujerearse, poniendo en peligro la integridad general de la muestra. Una vez que el tejido está debidamente preparado, suele tratarse con tintes de colores característicos. Estos tintes acentúan diferentes tipos de células y tejidos con colores específicos, lo que facilita a los profesionales médicos la identificación de características particulares. Sin embargo, esta mejora en visualización tiene un alto coste. En ocasiones, los tintes pueden dificultar el análisis informático de las imágenes al mezclarse de forma inadecuada, traspasarse al fondo o alterar el contraste entre los distintos elementos. El último paso del proceso consiste en digitalizar la muestra. Se toman imágenes de alta resolución del tejido con distintos aumentos, lo que permite su análisis por ordenador. Esta etapa también tiene sus obstáculos. Factores como una calibración incorrecta de la cámara o unas condiciones de iluminación inadecuadas pueden distorsionar o hacer borrosas las imágenes. Además, las imágenes de porta completo obtenidas so de tamaño considerable, complicando aún más el análisis. En general, si bien la preparación, la tinción y la digitalización de las muestras de microscopía médica son fundamentales para el análisis digital, cada uno de estos pasos puede introducir retos adicionales que deben abordarse para garantizar un análisis preciso. Además, convertir un volumen de tejido completo en unas pocas secciones teñidas reduce drásticamente la información 3D disponible e introduce una gran incertidumbre. Las soluciones de aprendizaje profundo (deep learning, DL) son muy prometedoras en el ámbito de la medicina personalizada, pero su impacto clínico a veces se ve obstaculizado por factores como la limitada generalizabilidad, el sobreajuste, la opacidad y la falta de interpretabilidad, además de las preocupaciones éticas y en algunos casos, los incentivos privados. Por otro lado, la variabilidad de las imágenes histológicas complica el desarrollo de métodos robustos de DL. Para superar estos retos, esta tesis presenta una serie de métodos altamente robustos e interpretables basados en principios clásicos de histología, imagen médica, matemáticas y arte, para alinear secciones de microscopía y analizar sus colores. Nuestra primera contribución es ABANICCO, un innovador método de análisis de color que ofrece una segmentación de colores objectiva y no supervisada y permite su posterior refinamiento mediante herramientas fáciles de usar. Se ha demostrado que la precisión y la eficacia de ABANICCO son superiores a las de los métodos existentes de clasificación y segmentación del color, e incluso destaca en la detección y segmentación de objetos completos. ABANICCO puede aplicarse a imágenes de microscopía para detectar áreas teñidas para la cuantificación de biopsias, un aspecto crucial de la investigación de cáncer. La segunda contribución es un método automático y no supervisado de segmentación de tejidos que identifica y elimina el fondo y los artefactos de las imágenes de microscopía, mejorando así el rendimiento de técnicas más sofisticadas de análisis de imagen. Este método es robusto frente a diversas imágenes, tinciones y protocolos de adquisición, y no requiere entrenamiento. La tercera contribución consiste en el desarrollo de métodos novedosos para registrar imágenes histopatológicas de forma eficaz, logrando el equilibrio adecuado entre un registro preciso y la preservación de la morfología local, en función de la aplicación prevista. Como cuarta contribución, los tres métodos mencionados se combinan para crear procedimientos eficientes para la integración completa de datos volumétricos, creando visualizaciones altamente interpretables de toda la información presente en secciones consecutivas de biopsia de tejidos. Esta integración de datos puede tener una gran repercusión en el diagnóstico y el tratamiento de diversas enfermedades, en particular el cáncer de mama, al permitir la detección precoz, la realización de pruebas clínicas precisas, la selección eficaz de tratamientos y la mejora en la comunicación el compromiso con los pacientes. Por último, aplicamos nuestros hallazgos a la integración multimodal de datos y la reconstrucción de tejidos para el análisis preciso de la distribución de elementos químicos en tuberculosis, lo que arroja luz sobre las complejas interacciones entre las bacterias, las células huésped y el sistema inmunitario durante la infección tuberculosa. Este método también aborda problemas como el daño por adquisición, típico de muchas modalidades de imagen. En resumen, esta tesis muestra la aplicación de métodos clásicos de visión por ordenador en el registro de microscopía médica y el análisis de color para abordar los retos únicos de este campo, haciendo hincapié en la visualización eficaz y fácil de datos complejos. Aspiramos a seguir perfeccionando nuestro trabajo con una amplia validación técnica y un mejor análisis de los datos. Los métodos presentados en esta tesis se caracterizan por su claridad, accesibilidad, visualización eficaz de los datos, objetividad y transparencia. Estas características los hacen perfectos para tender puentes robustos entre los investigadores de inteligencia artificial y los clínicos e impulsar así la patología computacional en la práctica y la investigación médicas.Programa de Doctorado en Ciencia y Tecnología Biomédica por la Universidad Carlos III de MadridPresidenta: María Jesús Ledesma Carbayo.- Secretario: Gonzalo Ricardo Ríos Muñoz.- Vocal: Estíbaliz Gómez de Marisca

A guide to integrating immunohistochemistry and chemical imaging

© 2018 The Royal Society of Chemistry. Chemical imaging provides new insight into the fundamental atomic, molecular, and biochemical composition of tissue and how they are interrelated in normal physiology. Visualising and quantifying products of pathogenic reactions long before structural changes become apparent also adds a new dimension to understanding disease pathogenesis. While chemical imaging in isolation is somewhat limited by the nature of information it can provide (e.g. peptides, metals, lipids, or functional groups), integrating immunohistochemistry allows simultaneous, targeted imaging of biomolecules while also mapping tissue composition. Together, this approach can provide invaluable information on the inner workings of the cell and the molecular basis of diseases