Virtual Microscopy (VM) is the technique of digitizing a glass microscope slide with commonly used objective magnifications producing a digital virtual microscope slide.  A virtual microscope slide is equivalent to the original glass slide on a microscope and will provide diagnostic image quality.

Biopathology Process for Digitizing Slides

The goal of the Biopathology Center (BPC) is to fully-utilize its virtual microscopy technology and equipment by scanning all new slides as they arrive for processing.  The process for digitizing the glass slides would require that a staff member perform the following daily operations (see table below):

1. Each morning slides scanned the day prior will be quality reviewed by biopathology staff.
2. Any slides with the poor quality will be rescanned as necessary to obtain an acceptable image.
3. The BPC staff will routinely load slides utilizing the 120-slide autoloader each afternoon.
4. To reduce the risk of data loss, all images will be stored on drives that are backed up daily.
5. As slides are successfully digitized, they will be made available either via a local area network (LAN) or through the Internet.

Virtual Microscopy Process Flow

More information about Virtual Microscopy

Past Success with Virtual Microscopy

Tissue Microarray (TMA) Project

VM has been successfully utilized for scanning, viewing, and annotating slides for a Tissue Microarray (TMA) project.  The slides were scanned using an Aperio Technologies ScanScope and made available for annotation via the Internet to selected pathologists.  Each pathologist was assigned three cases and sent instructions for viewing those three cases.  While viewing the digital slides with the Aperio ImageScope software, each pathologist was asked to annotate the desirable areas from which the cores were to be taken. Since the BPC typically prepares four blocks for each review, each pathologist was asked to prioritize the areas from which the cores were taken. A minimum of 4 - 1.0mm cores (ideally 12 cores) are needed for accurate diagnosis. When finished making annotations, the pathologist would save the work by clicking on the ‘Save’ icon in the annotation window, naming the file as the original file name, saving the file as an extensible markup language (.xml) file, and then emailing the newly created file to the BPC where the cores were taken.

Each pathologist participating in the TMA project was asked to download and install ImageScope, available free from Aperio Technologies, to view and annotate the images made available via the Internet.  After being viewed and annotated, a new file was created and emailed to the BPC where annotations were reviewed, marked, and cored as requested.

Pathology Review of Difficult Cases

VM has also been utilized by the COG Pathology Committee, at the semi-annual COG meetings, for the pathology review of difficult cases.  These cases were scanned, digitized, stored, annotated, and reviewed using a laptop personal computer and a LCD projector.

Future Plans for Virtual Microscopy

As with any new technology, it is necessary to explore potential uses for Virtual Microscopy (VM) and the BPC is currently working with the COG and GOG pathology committees to explore additional uses.  While factoring in logistical issues related to shipping glass slides, many opportunities and suggestions have been mentioned concerning VM.

Web-based Review of Rhabdomyosarcoma Cases

The pathology review process could be more efficient by utilizing virtual microscopy and allowing for web-based pathology review to confirm eligibility as required per protocol.  Current initiatives at the BPC include digitizing all slides received related to rhabdomyosarcoma cases and making these slides available for web-based pathology review.  As with any new technology, a quality review is also being performed by each reviewer. For this review, the glass slides are viewed and compared to the digitized images.

Neurblastoma Image Analysis Project

The BPC is also collaborating with Dr. Hiroyuki Shimada, Children’s Hospital – Los Angeles, and the Ohio State University on a neurblastoma image analysis project.  The two primary objectives of the collaboration will consist of virtual slide review and automated image analysis.  With neuroblastoma having a well-established decision structure, the goal is to provide automated quantification of neuroblastoma cases. However, this will require the quantification to be studied, implemented and validated.

Conclusion

Virtual Microscopy (VM) will facilitate translational research in the pediatric cancer by providing both a web-based pathology review and a digital archive documentation of the original pathology material. This will allow for a retrievable database of submitted material for confirmation of eligibility criteria.  VM can also enhance the selection of research material by providing an on-line review of original material prior to an investigator selecting or requesting tissue.