Real-time transmission of full-motion echocardiography over a high-speed data network: Impact of data rate and network quality of service

With high-resolution network transmission required for telemedicine, educat ion, and guided-image acquisition, the impact of errors and transmission ra tes on image quality needs evaluation. Methods: We transmitted clinical echocardiograms from 2 National Aeronautic s and Space Administration (NASA) research centers with the use of Motion P icture Expert Group-2 (MPEG-2) encoding and asynchronous transmission mode (ATM) network protocol over the NASA Research and Education Network. Data r ates and network quality (cell losses [CLR], errors [CER], and delay variab ility [CVD]) were altered and image quality was judged. Results: At speeds of 3 to 5 megabits per second (Mbps), digital images wer e superior to those on videotape; at 2 Mbps, images were equivalent. Increa sing CLR caused occasional brief pauses. Extreme CER and CDV increases stil l yielded high-quality images. Conclusions: Real-time echocardiographic acquisition, guidance, and transmi ssion Is feasible with the use of MPEG-2 and ATM with broadcast quality see n above 3 Mbps, even with severe network quality degradation. These techniq ues can be applied to telemedicine and used for planned echocardiography ab oard the International Space Station.