Pathology continues to implement innovations in digital technology solutions. Whole slide imaging uses glass slide scanning capabilities to produce digital images. Advanced technology in whole slide scanning hardware and software provide ready access for interpretations and consulting while also protecting patient data.
WSI, also known as virtual microscopy, facilitates data preservation and plays a crucial role in telepathology, preserving precious pathology data as digital files. Pathology regulatory organizations, including the College of American Pathologists, offer guidelines for clinical validation. WSI is also approved by the US Food and Drug Administration for primary diagnosis.
Between 250,000 to as many as 440,000 patients die as a result of a medical error in the U.S. each year. In fact, it is the third leading cause of death in America after heart disease and cancer. WSI helps reduce the risk of misdiagnosis due to deteriorating or lost patient data with improved preservation and storage methods.
What Is Whole Slide Imaging?
Whole slide imaging is a relatively new form of medical data preservation used in the digital pathology field. This technology allows pathologists to scan microscopy slides and convert them into high-resolution digital images using advanced software and hardware. WSIs are used in search histopathology as well as in cancer diagnoses.
WSI provides a valuable triage tool. It also expedites workflow with high-throughput scanners that can handle up to 400 slides. Feedback to the laboratory is also expedited in cases where samples require modification. Continuous technological advances also offer opportunities for specialized digitization of:
- Whole tissue mounts
- Larger glass slides
- Fluorescent-labeled sections
- Smear
How are Slides Preserved?
WSI uses a four-step sequential process:
- Image Acquisition
The hardware used for image acquisition includes image capture and image display. WSI digital scanners with a high-resolution camera capture sequential images via tiled or line-scanning and assemble or “stitch” the images into an exact replica of the glass slide to create the virtual slide (VS).
- Storage
WSI is stored in a pyramid format. Multiple magnification levels provide researchers and pathologists with different information. By zooming in and out of a WSI, they can determine what information they wish to gather before reaching a decision.
- Processing
WSI preprocessing is often used to facilitate human or machine analysis, including artifacts detection, color variation, and pathology-specific data augmentation. When histological tissues are digitized, it introduces artifacts and variations that can be addressed before tissue analysis.
- Visualization
The intended use of the VS dictates how they are viewed and managed. For internal purposes, locally installed image-viewing software is used, while collaborative software is stored on network servers for remote access. Many systems allow doctors to annotate the image and export them to various file formats, while others use finger touch annotation using an onscreen virtual keyboard.
Viewing devices include smartphones, XDesk, or Microsoft Surface. Interactive discussion capabilities allow for collaboration among teams using VS images viewed remotely. Another factor is VS resolution, determined by the magnification used during image acquisition. For example, suitable magnification for surgical pathology and immunohistochemistry requires × 20 magnification, while cases such as cervicovaginal cytology require higher diagnostic accuracy at × 40.
Why Whole Slide Imaging is Important
With the validation of WSI in the field of pathology, medical facilities and pathologists alike are seeing avenues opening for increased applications in routine practice. The many benefits of WS include the following:
Storage
The ever increasing demand for physical space to store glass slides is easily managed with WSI and VS. They enable safe digital archiving of routine H&E slides and preservation of special stains, immunochemistry, or fluorescent-labeled slides. Samples remain fresh and are converted free from artifacts. Once stored, data can be linked to the HIS, ready for review, along with a patient’s electronic health records. Permanent digital records can be shared for consultation, sent for further molecular testing, or used for medico-legal and forensic purposes. Examples are preserved without fear of deterioration, allowing specialists to draw their own conclusions without dependence on the review of initial findings.
Pathology Education
WSI helps standardize pathology education using identical slides viewed simultaneously by remote students or in the classroom. As a result, training in the interpretation of immunohistochemistry or electron microscopy offers exposure to students in areas that are in dire need of these specialized fields. Because the WSI images can also be annotated, it provides students with a holistic view of diagnostics. It also makes education in this critical field more cost-effective with reduced need for classrooms and costly equipment.
Reliable Results
WSI produces quick and reliable results with reduced waiting times. As well other diagnostic applications include intra-operative frozen section diagnosis through remote telepathology. As a result, consultation with experts for WSI-based frozen section and permanent section diagnosis is available both as on-site and remote interpretation to improve diagnosis on a range of pathologies. WSI also facilitates quality assurance in surgical pathology and cytopathology.
Research
WSI is also a critical tool in providing biomarkers for biotechnology and pharmaceutical research allowing for the assessment and scoring of biomarkers quickly and objectively. If biomarker heterogeneity occurs, fluorescent WSI or multispectral imaging facilitates multiplexed analysis, supporting the discovery of drugs or further biomarkers. It can also be used to develop oncologic biomarker strategies to help support drug discovery.
Cost Cutting
WSI can help cut costs across multiple areas, from education and training to staffing at medical facilities. It also eliminates transportation costs, while high-throughput scanners reduce the need for overtime and multiple scanners at labs. Further savings are realized through the freeing up of physical storage space for slides, allowing facilities to acquire additional space for patient care.
Secure Medical Data
Medical data is both highly sensitive and vulnerable to loss and damage. Reliable equipment and practices through WSI provide ease of access from secure storage with no risk of breakage, loss, or deterioration of staining quality.
With ongoing technological advances, WSI will continue to see improvements in digital scanner capabilities. Image visualization methods will also become more accurate, and pathologists and medical professionals can also expect to see the integration of artificial intelligence-derived algorithms. These advancements provide opportunities for new applications. Ease of access through the internet facilitates collaboration, decreasing the risk of mistakes and improving patient outcomes.
Specialist Direct offers a team of U.S., Board-Certified pathologists who interpret digital pathology studies within 1 hour, 24/7/365. This service is unique in that it accommodates STAT studies and after-hours cases. To learn more about telepathology, contact Specialist Direct.
