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, education, and guided-image acquisition, the impact of errors and transmission rates on image quality needs evaluation.


METHODS
We transmitted clinical echocardiograms from 2 National Aeronautics and Space Administration (NASA) research centers with the use of Motion Picture Expert Group-2 (MPEG-2) encoding and asynchronous transmission mode (ATM) network protocol over the NASA Research and Education Network. Data rates and network quality (cell losses [CLR], errors [CER], and delay variability [CVD]) were altered and image quality was judged.


RESULTS
At speeds of 3 to 5 megabits per second (Mbps), digital images were superior to those on videotape; at 2 Mbps, images were equivalent. Increasing CLR caused occasional, brief pauses. Extreme CER and CDV increases still yielded high-quality images.


CONCLUSIONS
Real-time echocardiographic acquisition, guidance, and transmission is feasible with the use of MPEG-2 and ATM with broadcast quality seen above 3 Mbps, even with severe network quality degradation. These techniques can be applied to telemedicine and used for planned echocardiography aboard the International Space Station.
Cardiovascular Imaging Center, Department of Cardiology, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
M L
ML
Main
D
D
Foltz
M S
MS
Firstenberg
E
E
Bobinsky
D
D
Bailey
B
B
Frantz
D
D
Pleva
M
M
Baldizzi
D P
DP
Meyers
K
K
Jones
M C
MC
Spence
K
K
Freeman
A
A
Morehead
J D
JD
Thomas
D016477:Artifacts; D004452:Echocardiography / Q000592:standards; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000592:standards*; D011786:Quality Control; D017216:Telemedicine / Q000592:standards*; D014481:United States; D018557:United States National Aeronautics and Space Administration