Correlation-based blood-flow velocity estimation: effect of transverse spread of flow velocity and flow velocity gradients

In recent years, a new method to measure transverse blood flow, based on the decorrelation of the radio frequency (RF) signals has been introduced. We investigated the decorrelation characteristics of transverse blood flow using an intravascular ultrasound (IVUS) array catheter by means of computer modeling. Blood was simulated as a collection of randomly located point scatterers; moving this scattering medium transversally across the acoustical beam represented flow. Two velocity profiles were simulated: random spread of blood-flow velocity and a linear blood-flow velocity gradient. RF signals were used to calculate the decorrelation pattern. The results were compared to the ones for plug blood-flow showing a good agreement between them. This agreement suggests that the decorrelation properties of an IVUS array catheter for measuring quantitative transverse blood flow is not affected by different transverse blood-flow conditions.