Four years experience with teleneuropathology.

Between 2002 and 2005, we made 343 intraoperative frozen section diagnoses with a telepathology system, which connected a neurosurgical department to our department of pathology. An expert neuropathologist performed at least one brief gross examination, and this was followed by a smear preparation and a frozen section slide for each case. Frozen section diagnosis lasted on average 26.1 min, calculated from the beginning of gross examination until the surgeon was given the diagnosis. The majority of cases (283 or 83%) were diagnosed in 15-40 min. The mean time needed for macroscopic examination was 3.0 min, time for staining 4.2 min, smear diagnosis took 5.4 min and time for histological diagnosis 10.7 min. Telemicroscopy of a smear slide took 11 times longer compared with light microscopy, and telemicroscopy of a frozen section slide took 16 times longer than with light microscopy. In 6% of cases, the telepathology software posed technical problems, which delayed the time of diagnosis, but not by more than 4 min. We were able to render a diagnosis in all cases (system reliability 100%). After eliminating sampling errors (i.e. cases with no diagnostic material in the frozen section slides and/or in smear preparations), the diagnostic accuracy for telepathology was 97.9%.