What is virtual microscopy?
“Virtual microscopy” is the software-assisted manipulation of high-definition digital images of tissue sections, to simulate the experience of examining glass slides under a standard optical microscope. Magnifications of up to × 40 can be achieved.
Why use virtual microscopy?
The advantages of using digital images for microscopic examination of pathology specimens are that they are easily duplicated and do not deteriorate. In addition, they can be stored, catalogued and managed with relative ease.
How can virtual microscopy be used?
Teaching, testing and e-learning
Computers are now readily available in educational institutions and are cheaper than microscopes.
- Virtual microscopy makes it possible to provide students or residents with access to slides from rare cases that they would not traditionally see, and without the risk of breaking valuable glass slides.
- All of the participants can view the same slide, ensuring that they benefit from exposure to the correct information.
- Software allowing 360-degree rotation of images allows them to be reviewed in any orientation including orienting the epidermis at the top of dermatopathological slides; this was not possible in the past and was problematic when using slides for teaching.
- With suitable software, it is possible to incorporate annotations, such as circles and arrows, clinical photographs, images of pathological morphology or radiology. By attaching a discussion, multimedia, web links and references, the usefulness of the images as teaching tools can be enhanced further.
- Virtual microscopy is useful for independent study (e-learning) and, with additional software, can provide instant real-time feedback, allowing learners to assess their own performance. Once the images and ancillary material are online, they can be accessed for review and further study at any time of day.
Continuing Medical Education and External Quality Assurance
Virtual microscopy is also useful in continuing medical education (CME) or continuing professional development (CPD) and external quality assurance (EQA).
- The incorporation of examinations with integrated multiple-choice questions, makes it possible to accrue CME credit online. Accruing CME credit is becoming increasingly important for specialists. In some countries it provides higher salaries, as is currently the case in Europe. In other countries, it is necessary for renewal of licensure and maintenance of specialty certification and is mandatory. The latter is already the case in the USA, along with mandatory certification examinations.
- Digital pathology has been proven globally as a strong tool for CME, CPD and EQA type programmes. Several key organizations, including the College of American Pathologists, the American Society for Clinical Pathology and the Royal College of Pathologists of Australasia, are already using digital pathology to deliver accredited CME exercises. The European Academy of Dermatology and Venereology offers a quarterly Clinco-Pathological Self-Assessment Module to their members and the American Society of Dermatopathology an interactive case study of the month to theirs, both of which use virtual dermatopathological images. In addition, a number of pathology subspecialty EQA programmes in the UK use digital pathology.
Consultation between pathologists and clinicians around the globe is easily manageable. Suitable software allows incorporation with the slide data of:
- Gross morphology
- Clinical photographs
- Radiological images
- Clinical information
Storage of scanned images
Some institutions use virtual pathology for filing purposes.
- With increasing lack of storage space for histopathological slides, scanning pertinent slides and then discarding the original glass slides, while keeping the blocks, has become an option. This also reduces salary costs for employees, who no longer need to retrieve glass slides from storage.
- Storage of large banks, or software including digital slides, can be most easily achieved in data centers (cloud-based or local), and individual collections can be stored or backed up on hard drives.
Disadvantages of virtual microscopy
Disadvantages of virtual microscopy may include:
- Not all centres have histopathology slide scanners, although these are now becoming more common. It is possible to send slides for scanning at commercial centers for a set fee.
- High speed Internet connection is necessary to view the large files (512 Kbps for the above image)
- Digital slides scanned by different brands of scanner and software used for viewing the images may be incompatible. Current software can accommodate most types of digital slides, regardless of origin.
- Software using FlashPlayer™ is currently incompatible with certain tablet computers, including the iPad™.
Research into the validity of virtual microscopy
Studies of diagnostic accuracy using virtual microscopy have been done comparing use of glass slides to digital slides as well as photomicrographs to digital slides. See references below. This is not a comprehensive list.