Among the limitations of continuous-wave Doppler, what cannot be determined?

Continuous-wave Doppler ultrasound technology is notable for its ability to measure the velocity of blood flow, but it has certain limitations, particularly concerning the specificities of the data it can provide. One of these significant limitations is that it does not offer depth information regarding the location of blood flow.

When using continuous-wave Doppler, the system continuously sends and receives ultrasound waves, capturing signals from all moving reflectors (such as red blood cells) along the entire length of the beam. This means that the device provides an average flow velocity without specific localization; hence, the depth from which the signals are coming cannot be discerned. In contrast, pulsed-wave Doppler can determine the depth of the sample volume, allowing for more precise localization of blood flow within a specific vessel segment.

The inability to ascertain depth information limits the ability to differentiate between signals from different vessels that may be situated at varying depths along the ultrasound beam. Understanding this limitation is essential for vascular specialists when interpreting Doppler studies, as it directly impacts the assessment of vascular conditions and planning for interventions.