Doppler angle correction

Last revised by Benjamin Li Shun Chan on 24 Aug 2023

Doppler angle correction refers to an imaging post-processing method used to adjust for the effects of insonation angle on the Doppler shift.

Measurement of flow velocity with Doppler imaging is dependent on the angle between the ultrasound beam and the target (insonation angle), with the maximum and true velocity achieved at 0 degrees (parallel to the target). In most clinical scenarios, an insonation angle of 0 degrees is impractical and angle correction can still be applied to achieve an accurate velocity measurement 1. Angle correction is considered accurate for diagnostic purposes at insonation angles less than 60 degrees 1. At angles above 60 degrees, an error of up to 20-30% in calculated velocities can occur 2. If serially evaluating flow velocities in a vessel, it is recommended to maintain a similar Doppler angle between studies 3.

On most modern ultrasound machines, the user manually applies Doppler angle correction by aligning a cursor with the long axis of the vessel 1.

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