Virtual microscopy and public-key cryptography for Internet telepathology

The Internet is a potentially inexpensive, widely available medium for tele pathology, 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, 2 4 bit/pixel resolution. The image files were saved in JPEG format at medium compression, attached to text files with patient information, encrypted fo r security in the S/MIME format using a digital signature and digital envel ope, and transmitted by email. Received email files were decrypted automati cally 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 telep athology 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 publ ic-key cryptography offers an effective and relatively inexpensive method o f telepathology consultation. The method is best suited for the diagnosis o f small biopsy specimens that require the transmission of only a few digita l images that represent the majority of the biopsy materials.