Doppler Ultrasound Calibration: Instrumentation and Protocols for Quality Assurance
James C. Conti
Just as ultrasound imaging modalities became quantitative with the use of appropriate phantoms and protocols, Doppler ultrasound studies can now be implemented as quantitative tools by the use of a reliable flow phantom and appropriate procedures. The need for equipment to calibrate Doppler ultrasound instrumentation has been properly noted in scientific literature and textbooks.1-2 In addition, the design characteristics of an ideal flow phantom have been defined.1 A device and simple protocol have been evaluated that allows a Doppler user to assure, at the 97% confidence level, that the peak velocities determined from any particular patient are accurate. At the same time, the volume flow accuracy can be assured at the 99% confidence level. Protocols and instrumentation have been designed to generate a patient-unique calibration curve in less than one minute. Ease of implementation in the clinical setting was a prime consideration in protocol design. The information is stored in permanent form along with the patient records so that post evaluation of the data or long term patient tracking is possible. Evaluation of the flow field of the phantom and considerations required to properly implement the calibration step in the clinical environment will be presented. Ramifications for patient safety and cost containment will be discussed.
1 Evans DH, McDicken WN, Skidmore R, Woodcock JP, (1989) Doppler
Ultrasound, John Wiley & Sons, Chichester.
2 AIUM Doppler Standards Subcommittee, Performance Criteria and
Measurements For Doppler Ultrasound Devices (1993).
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