Local Applications of Digital Microscopy
Digital microscopic image capture and transmission is typically associated with telepathology (making anatomic pathology diagnoses at a distance). This association with remote diagnosis distracts us from those important applications of digital image capture unrelated to diagnosis at a distance. A few currently used applications of digitization of microscopic images are listed below:
Education: Typical and atypical cases of diseases can be collected and organized for review and teaching purposes. These images can be exported into printed documents (using a word processor), can be transferred to another computer in the laboratory for ready access by students as "typical" teaching cases or for use by technologists as a reference for "atypical" presentations of various diseases or typical presentations of rare diseases.
In our laboratory, images are collected for teaching sets in cytology and hematology. In cytology, one student's project is to create an interactive atlas of the Bethesda cytology classification system. In hematopathology, images are being collected for an interactive atlas of hematology to serve as a computerized and printer bench references.
Quality Assurance: Kodachrome slide-based survey materials from accrediting agencies, such as the College of American Pathologists, are regularly sent to small clinical laboratories for proficiency testing (PT). In our laboratory, these images are digitized and incorporated into an annotated reference that is updated with each PT cycle. Thus, each remote laboratory has access to a constantly evolving knowledge resource of the "minimum" knowledge requirements of the accrediting agencies. We are expanding our off-site laboratory PT program with review of selected peripheral blood smear slides from out patient population and will incorporate key images from these challenges in the printed reference book as well.
Convenience: Each pathologist learns that there are certain cases that certain clinicians want to review under the microscope. It is simpler to capture those images digitally at the time of initial examination than to scramble for the slides at a later time when the clinician shows up at an unexpected time.
Similarly, in pathology there are cases in which diagnostic microscopic fields are time-consuming to locate, such as malarial parasites in a blood smear. It is more efficient to capture an image of each parasite as it is encountered and then review the collected images with a colleague, instead of having the second (and possibly a third) pathologist take time to scan the blood smear again looking for a few diagnostic fields.
Serial Monitoring of Patient Samples: Patients with hematopoietic disease (such as acute leukemia) are likely to have a number of bone marrow examinations during the treatment of their disease. Stored images of these samples can provide a quick answer to questions of the initial bone marrow appearance and a simple means to evaluate changes in cellularity, proportion of normal and abnormal cells , and variation in cellular appearance without having to retrieve, scan, and re-file archived slides.
A Look Ahead: We should all be aware that our communication is rapidly evolving from physical storage of documents on-site to digital storage of documents at any site. If you use paper or other physical medium for information storage, it must be physically close to you for access. If you are accessing a digital document, it can be retrieved with nearly equivalent speed whether it is located at a computer on your desk or a mainframe computer around the world. Current image acquisition hardware and software are not yet suitable for economically storing all pathology images as of this writing, but digital image storage for gross and microscopic pathology soon will evolve to provide a viable alternative to nearby on-site storage of glass microscopic slides, thus freeing valuable floor space and saving manpower for consultation.
Harrison W. Pratt, DO