Standardization of Doppler Echocardiographic Signals
James C. Conti, Ph.D. and Elaine R. Strope, Ph.D., D. J. Rohde, C. L. Hanawalt,* R.D.M.S., K. Scott,* R.D.M.S
Dynatek Laboratories, Inc., Galena, MO, *St. John’s Hospital, Springfield, MO
A flow standard or phantom has been developed that allows the cardiologist, or other medical professional to assure that the flow velocity values they are obtaining are indeed reliable. Proven technologies have been utilized to fabricate a device that generates highly reproducible and reliable pulsatile flow up to 6 meters per second. Internationally recognized experts in the area of cardiovascular flow dynamics have contributed to this project. It is expected that this standard will be reproducible for at least 10 years although follow-up calibrations are planned.
After initial fabrication, the flow field of the EchoCal (Model CD) flow standard was mapped at the Laser Doppler Laboratory of Memphis State University. It was found that all regions within the flow field were accurate to approximately 1% with a pulse to pulse reproducibility of 1%.
The EchoCal flow phantom was then used to evaluate several clinical ultrasound machines at four medical centers. Results were mixed but did indicate that nearly 30% of all the devices evaluated were irreproducible or displayed Doppler velocity signals more than 25% in error.
Dynatek Laboratories, Inc., Fourth and Main, PO Box 254, Galena, MO 65656