Doppler flow measurement using surface integration of velocity vectors (SIVV): In vitro validation

Blood flow measurement using an improved surface integration of velocity ve ctors (SIVV) technique was tested in in vitro phantoms, SIVV was compared w ith true how (12-116 mL/s) in a steady-state model using two angles of inso nation (45 degrees and 60 degrees) and two vessel sizes (internal diameter = 11 and 19 mm), Repeatability of the method was tested at various flow rat es for each angle of insonation and vessel. In a univentricular pulsatile m odel, SIVV flow measured at the mitral inlet was compared to true flow (29- 61 mL/s), Correlation was excellent for the 19-mm vessel (r(2) = 0.99). The re was a systematic bias but close limits of agreement (mean +/- 2 SD = -24 .1% +/- 7.6% at 45 degrees; +16.4% +/- 11.0% at 60 degrees), Using the Il-m m vessel, a quadratic relationship was demonstrated between between SIVV an d true flow (r(2) = 0.98-0.99), regardless of the angle of insonation, In t he pulsatile system, good agreement and correlation were shown (r(2) = 0.94 , mean +/- 2 SD = -4.7 +/- 10.1%), The coefficients of variation for repeat ed SIVV measurements ranged from 0.9% to 10.3%. This method demonstrates pr ecision and repeatability, and is potentially useful for clinical measureme nts. (C) 2000 World Federation for Ultrasound in Medicine & Biology.