What is the primary function of Doppler ultrasound?

Doppler ultrasound primarily focuses on evaluating blood flow and measuring the velocity of moving blood cells. This technique utilizes the Doppler effect, which describes how the frequency of sound waves changes in relation to the motion of a sound source, such as red blood cells within blood vessels. When applied in sonography, it allows healthcare professionals to assess both the direction and speed of blood flow, which is crucial in diagnosing various cardiovascular conditions.

The other options, while related to ultrasound technology, do not represent the primary function of Doppler ultrasound. Measuring tissue density pertains more to standard imaging techniques rather than Doppler-specific principles, assessing organ size involves basic anatomical imaging, and capturing 3D images pertains to advanced imaging modalities that are not the primary objective of Doppler ultrasound. Instead, Doppler's unique capability to analyze blood dynamics directly supports its designated role in clinical practice.