Virtual microscopy and public-key cryptography for Internet telepathology

The Internet is a potentially inexpensive, widely available medium for telepathology, but there are concerns about its reliability and security. Using a digital camera, 41 photomicrographs of transbronchial biopsies, at x 100 optical magnification, were captured and digitized at 2700 x 3400 pixel, 24 bit/pixel resolution. The image files were saved in JPEG format at medium compression, attached to text files with patient information, encrypted for security in the S/MIME format using a digital signature and digital envelope, and transmitted by email. Received email files were decrypted automatically and the images viewed with standard software. Telepathology diagnoses were compared with original interpretations. The images averaged 810 kByte in size. The encryption and decryption did not cause significant delays in overall transmission time and, together with transmission, did not produce noticeable image degradation. The received image files could be viewed in a manner that simulated light microscopy. There was agreement between telepathology and original diagnoses in 92% of the cases. All the discrepancies were due to inadequate area selection because the pathological features of interest were present in histological levels other than those photographed. The use of high-resolution digital photomicrography, the Internet and public-key cryptography offers an effective and relatively inexpensive method of telepathology consultation. The method is best suited for the diagnosis of small biopsy specimens that require the transmission of only a few digital images that represent the majority of the biopsy materials.