Ex Vivo Digital Microscopy Techniques in Surgical Pathology

Ex vivo digital microscopy uses light in the visible and adjacent spectra to obtain digital images of tissues. They are optical imaging techniques that allow the acquisition of digital images of tissues with minimal or no tissue preparation and are currently available for evaluation of fresh and/or fixed tissues. This review will provide an overview of the different types of ex vivo digital microscopy techniques, including confocal microscopy (CM), optical coherence tomography (OCT), stimulated Raman Spectroscopy (SRS), light sheet microscopy (LSM), microscopy with ultraviolet excitation (MUSE), structured illumination microscopy (SIM), and nonlinear microscopy (NLM). Except for OCT and SRS, all the other tissue imaging techniques require labeling of tissues with fluorescent dyes to obtain digital images. An advantage of several of these techniques, including fluorescence CM, SRS, LSM, MUSE, SIM, and NLM, is that they can produce hematoxylin and eosin-like images. The promising potential of ex vivo digital microscopy techniques in surgical pathology practice is supported by several retrospective and limited prospective studies. Applications of ex vivo digital microscopy techniques include real-time evaluation of fresh tissue at the bedside in clinics and radiology suites, as well as intraoperatively in pathology laboratories. These techniques have great potential for incorporation into standard-of-care surgical pathology practice.