New draft guidance issued by the US Food and Drug Administration (FDA) offers a high-level roadmap for developers of digital imaging devices known as digital pathology whole slide imaging devices.
As explained by FDA in the guidance and elsewhere on its website, the devices are used to convert analog microscope images into digital images, making it easier to diagnose patients without the use of a microscope. The devices generally consist of a larger system of devices (camera, scanner, computer, monitor and software).
FDA regulates imaging devices under 21 CFR 864.3600—FDA's regulatory code for microscopes and accessories—as Class I (low-risk) devices subject to "general controls" but otherwise exempt from FDA's premarket notification [510(k)] process.
But if the devices are exempt from most regulation, why is FDA taking the time to develop new guidance? As FDA explains, "Recent technological advances in digital microscopy, in particular the development of whole slide scanning systems, have accelerated the adoption of digital imaging in pathology, similar to the digital transformation that radiology departments have experienced over the last decade."
"Essential to the regulation of these systems is the understanding of the technical performance of the components in the imaging chain, from image acquisition to image display and their effect on pathologist’s diagnostic performance and workflow," FDA added.
FDA's draft guidance, Technical Performance Assessment of Digital Pathology Whole Slide Imaging Devices, is focused almost entirely on understanding the technical performance of each type of whole slide imaging (WSI) device, with an emphasis on the image acquisition and image display components of each device.
The guidance makes clear that FDA would like to see the interactions between a WSI device's various components using a block diagram. In addition, "Sponsors are encouraged to provide additional diagrams, illustrations, and photographs of their devices as part of their submissions," FDA says in its guidance.
In addition, information should be provided about each component of the device, such as the slide feeder, light source, imaging optics, mechanical scanner movement, digital imaging sensor, image processing software, image composition, image files formats, image review manipulation software, computer environment and display.
Other factors, including system-level assessments, spatial resolution, focusing tests, whole slide tissue coverage, stitching errors, user interface, labeling and quality control should also be assessed.
Comments on the guidance are due to FDA by 26 May 2015.
Technical Performance Assessment of Digital Pathology Whole Slide Imaging Devices (FR)