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.
Main
M L
ML
Cardiovascular Imaging Center, Department of Cardiology, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Foltz
D
D
Firstenberg
M S
MS
Bobinsky
E
E
Bailey
D
D
Frantz
B
B
Pleva
D
D
Baldizzi
M
M
Meyers
D P
DP
Jones
K
K
Spence
M C
MC
Freeman
K
K
Morehead
A
A
Thomas
J D
JD
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