Introduction to Digital Pathology from Historical Perspectives to Emerging Pathomics

The discipline of pathology spans the basic sciences, clinical medicine, and laboratory testing with the goals of studying the causes and effects of diseases. Whole slide imaging and virtual microscopy have led to the establishment of digital pathology as a new and exciting frontier to further study the pathobiology of a wide spectrum of diseases by providing access to high-resolution digital images of tissue samples. The interactive exploration of whole slide images (WSIs) of tissues has transcended the confinement of tissue samples to glass slides by providing access to virtual tissue samples at our fingertips to facilitate the expansion of our understanding about the causes, progression, and effects of diseases. Alongside this unprecedented access to virtual tissue samples without the need for physical light microscopes, large multidisciplinary research efforts have developed a wide range of methods to perform computational image analysis to harvest Pathomics data from WSIs. Nowadays, digital pathology represents a vibrant ecosystem of clinical, scientific, and engineering collaborative research efforts that spans the development of digital slide scanners to advances in computational hardware, framework, software, data management, image analysis, and machine learning. The goal of this chapter is to introduce the fundamental concepts and principles in digital pathology that underpin smooth and interactive viewing of WSIs in all modern software systems that led to advances in computational image analysis. We also introduce how Pathomics is positioned to impact healthcare through correlative analyses with clinical, laboratory, radiologic, genomic, and treatment response data through modern deep learning computer visions applications. In less than 20 years of development, digital pathology has been deployed for clinical use through telepathology while being actively enlisted as a powerful tool for clinical research to help discover patterns, relationships, and novel biomarkers to improve patient care and treatment. This chapter will describe the paradigm shift caused by virtual microscopy and provide insight into how digital pathology in transforming modern medicine.