Doppler flow measurement using surface integration of velocity vectors (SIVV): in vitro validation.
Blood flow measurement using an improved surface integration of velocity vectors (SIVV) technique was tested in in vitro phantoms. SIVV was compared with true flow (12-116 mL/s) in a steady-state model using two angles of insonation (45 degrees and 60 degrees ) and two vessel sizes (internal diameter = 11 and 19 mm). Repeatability of the method was tested at various flow rates for each angle of insonation and vessel. In a univentricular pulsatile model, 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). There 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 11-mm vessel, a quadratic relationship was demonstrated between between SIVV and true flow (r(2) = 0.98-0.99), regardless of the angle of insonation. In the pulsatile system, good agreement and correlation were shown (r(2) = 0.94, mean +/- 2 SD = -4.7 +/- 10.1%). The coefficients of variation for repeated SIVV measurements ranged from 0.9% to 10.3%. This method demonstrates precision and repeatability, and is potentially useful for clinical measurements.
Chew
M S
MS
Department of Anaesthesia and Intensive Care, Aarhus, Denmark. skejmc@aau.dk
Brandberg
J
J
Canard
P
P
Sloth
E
E
Ask
P
P
Hasenkam
J M
JM
D001783:Blood Flow Velocity; D018619:Echocardiography, Doppler, Pulsed; D006801:Humans; D009200:Myocardial Contraction; D015588:Observer Variation; D019047:Phantoms, Imaging; D011673:Pulsatile Flow; D015203:Reproducibility of Results