Increased accuracy of echocardiographic measurement of flow using automated spherical integration of multiple plane velocity vectors

The calculation of blood flow in the heart by surface integration of veloci ty vectors (SIVV) using Doppler ultrasound is independent of the angle. Flo w is normally calculated from velocity in a spherical thick shell with its center located at the ultrasound transducer. In a numerical simulation, we have shown that the ratio between minor and major axes of an elliptic flow area substantially influences the accuracy of the estimation of flow in a s ingle scan plane. The accuracy of how measurements by SIVV can be improved by calculating the mean of the values from more than one scan plane. We hav e produced an automated computer program that includes an antialiasing proc edure. We confirmed an improvement of flow measurements in a pulsatile hydr aulic flow model, the 95% confidence interval for single estimations being reduced from 20% to 10% (p < 0.05) using the newly developed software. We t hink that the SIVV method has important implications for clinical transthor acic echocardiography, (C) 1999 World Federation for Ultrasound in Medicine & Biology.