Experiences with an International Digital Slide Based Telepathology System for Routine Sign-out between Sweden and Hungary

Digital microscopy combines the benefits of traditional optical microscopy and the advantages of computer sciences. Using digital whole slides in all areas of pathology is increasingly popular. Telepathology or long distance diagnosis is one such area. In our study we have evaluated digital slide based histopathology diagnosis in an international setting, between Sweden and Hungary. Routine cases from the Sundsvall County Hospital (Landstinget Vasternorrland) were collected. Glass slides were scanned using Pannoramic 250 Flash II. (3DHISTECH Ltd., Budapest, Hungary). During the first round of evaluation the glass slides were shipped to Hungary for primary diagnosis. Two pathologists from Hungary, reading glass slides and one pathologist from Sweden reading digital slides signed out 500 cases. Pathologists from Hungary reached the hospital information system with a secure connection. During the second round the pathologists in Hungary reevaluated 200 from the 500 cases using digital slides after three months washout period. Diagnostic accuracy was calculated and diagnostic errors was graded according to clinicopathological consequences. In 182/200 (91%) cases digital and optical diagnoses were in full agreement. Out of the remaining 18 cases, 1 (0.5%) critical error was identified. In this case the error had therapeutic and prognostic consequence and no uncertainty either because of case complexity or poor image quality was recorded by the pathologist. We think language and communication issues as well as differences in minimal data sets of pathological reports and in guidelines used in Sweden and in Hungary are factors potentially limiting the widespread use of digital slides in a teleconsultation service provided to Sweden from Hungary. We found the quality of digital slides in our study setting acceptable to reach correct primary diagnosis in routine, unselected, random cases of a small-to-medium sized pathology department in Sweden.