Levy D J, Westra S J, Sayre J, Kimme-Smith C
Department of Pediatrics, UCLA School of Medicine, USA.
Acad Radiol. 1996 May;3(5):383-8. doi: 10.1016/s1076-6332(05)80669-5.
Color velocity imaging-quantitative (CVI-Q) is a new sonographic technique designed to measure volume flow (VF) in blood vessels. We attempted to validate VF measurements with CVI-Q in an in vitro model of the circulation.
We validated CVI-Q in a flow phantom mimicking physiologic conditions by connecting isolated porcine arteries 4-14 mm in diameter to a calibrated perfusion roller pump generating pulsatile flow with porcine blood. Pump flow was varied stepwise from 0 to 1,000 ml/min. CVI-Q VF measurements were performed using a 7.5-MHz linear array transducer. VF results then were compared with pump flow calibration values through linear regression.
A good correlation (r2 = .98-.99, slope = 0.88-1.02) was obtained from 0 to 400-600 ml/min. The degree of correlation depended on vessel diameter, with linearity being maintained over a somewhat larger range in medium-sized vessels. At higher flows, variability increased significantly.
VF measurements with CVI-Q are accurate in a physiologic flow range. At supraphysiologic flow rates, as are encountered within arteriovenous fistulae, CVI-Q may give inaccurate results. Awareness of possible pitfalls and limitations of the technique is important for obtaining accurate and reproducible results.
