A flat velocity profile in large vessels is termed plug flow, indicating that all or most of the blood is flowing at a single velocity per time unit.

See also Blood Flow Velocity.

Laminar flow is non turbulent flow in arteries with blood traveling in layers or laminae. In a straight vessel, the layer in the center flows at a greater speed with subsequent layers toward the vessel wall flowing at slower speeds.

See also Boundary Layer, and Half-Value Layer.

Biological flows vary throughout the cardiac cycle. The analog output can be filtered to give a pulsatile flow or mean flow signal.

(CFI) Color flow imaging is based on pulsed ultrasound Doppler technology. With this technique multiple sample volumes among multiple planes are detected and a color map for direction and velocity flow data is displayed.
Common mapping formats are BART (Blue Away, Red Towards) or RABT (Red Away, Blue Towards). Enhanced or variance flow maps show saturations and intensities that indicate higher velocities and turbulence or acceleration. Some maps utilize a third color (green) to indicate accelerating velocities and turbulence.
Color flow Doppler imaging is not as precise as conventional Doppler and is best used to scan a larger area and then use other Doppler modes to obtain more precise data.

See also Color Amplitude Imaging, Color Priority, and Color Saturation.

Bi-directional flow is measured in positive and negative directions.

See also Bi-directional Illumination, and Color Doppler Imaging.