The scale present on color flow ultrasonography exams does indicate the instantaneous speed at all locations on the plane defined by a cross-cut of the vessel. Duplex ultrasound outputs a time->velocity signal, but only focused on a single point. The traditional technique to estimate flow uses duplex, but is imprecise (~30% flow volume error, at best) and hindered by a lot of manual manipulations making it not reproducible along time and machine users.

Both techniques have disadvantages, making it difficult to obtain a good flow estimate. In the clinics, color flow Doppler is used as a mere location and speed rough indicator. I tried to solve this by including the vessel shape in a mathematical model, which makes the automated method surprisingly practical and efficient on those preliminary tests.