Experience with a dynamic inexpensive video-conferencing system for frozen section telepathology

To evaluate the feasibility of an inexpensive, generally applicable video-conferencing system for frozen section telepathology (TP).

A commercially widely available PC-based dynamic video-conferencing system (Picture-Tel LIVE, model PCS 100) has been evaluated, using two, four and six ISDN channels (128-384 kilobits per second (kbs)) bandwidths. 129 frozen sections have been analyzed which were classified by TP as benign, uncertain (the remark probably benign, or probably malignant was allowed), malignant, or not acceptable image quality. The TP results were compared with the original frozen section diagnosis and final paraffin diagnosis.

Only 384 kbs (3 ISDN-2 lines) resulted in acceptable speed and quality of microscope images, and synchronous image/speech transfer. In one of the frozen section cases (0.7%), TP image quality was classified as not acceptable, leaving 128 frozen sections for the analysis. Five of these cases were uncertain by TP, and also deferred by frozen section procedure (FS). One more benign and three malignant FS cases were classified as uncertain by TP. Three additional cases were uncertain by FS, but benign according to TP (in agreement with the final diagnosis). In one case, FS diagnosis was uncertain but TP was malignant (in agreement with the final diagnosis). Thus, test efficiency (i.e., cases with complete agreement) was 120/128 (93.8%, Kappa = 0.88) between FS and TP. Sensitivity was 93.5%, specificity 98.6%, positive and negative predictive values were 97.7% and 96.0%. Between TP and final diagnosis agreement was even higher. More importantly, there was not a single discrepancy as to benign-malignant. Moreover, there was a clear learning effect: 5 of the 8 FS/TP discrepancies occurred in the first 42 cases (5/42 = 11.9%), the remaining 3 in the following 86 cases (3/86 = 3.5%).

The results are encouraging. However, TP evaluation is time-consuming (5-15 min for one case instead of 2-4 min although speed went up with more experience) and is more tiring. The system has the following technical drawbacks: no possibility to point at objects or areas of interest in the life image at the other end, resolution (rarely) may become suboptimal (blocky), storage of images evaluated (which is essential for legal reasons) is not easy and no direct control of a remote motorized microscope. Yet, all users were positive about the system both for telepathology and personal contact by video-conferencing.

With a relatively simple videoconferencing system, accurate dynamic telepathology frozen section diagnosis can be obtained without false positive or negative results, although a limited number of uncertain cases will have to be accepted.