COLOR VELOCITY FLOW MEASUREMENT - IN-VITRO VALIDATION AND APPLICATIONTO HUMAN CAROTID ARTERIES

Ultrasound measurement of volume blood flow is potentially useful for many clinical situations, yet practical implementation and use are res tricted by the many instrumentation and blood flow limitations that ca n arise. Colour velocity imaging offers a number of theoretical advant ages over methods based on duplex imaging. We evaluated a colour veloc ity flow measurement system (CVI-Q, Philips) both in a flow phantom an d in vivo in the extracranial carotid arteries of normal volunteers. O ver a range of constant (50-1200 ml/min) and pulsatile (92-366 ml/min) flows and using both steered and unsteered beams with beam angles of 30 degrees and 40 degrees, errors usually within 5% were obtained for constant flow and within 10% for pulsatile flow. However, with a beam angle of 70 degrees, higher errors of 20% were obtained for pulsatile flow. The reproducibility of flow measurements made using both anterio r and posterior-lateral scanning approaches was determined in the comm on (CCA), internal (ICA) and external carotid (EGA) arteries of 18 vol unteers. A greater reproducibility was found using the posterior-later al approach (CCA 6.27%; ICA 9.8%), and mean (SD) flow values were 376 ml/min in the CCA and 255 ml/min in the ICA. The ratio of (ICA + ECA)/ CCA flow calculated for each subject individually was mean (SD) 0.95 ( 0.11). Insonation from an anterior approach resulted in lower reproduc ibility and lower flow values. In conclusion, colour flow velocity ima ging allows repeatable reproducible measurements of CCA and ICA flow, but results are optimal if a posterior-lateral scanning approach is us ed. (C) 1997 World Federation for Ultrasound in Medicine & Biology.