What is a significant limitation of continuous-wave Doppler?

The significant limitation of continuous-wave Doppler being the inability to define precise locations of flow patterns is rooted in the fundamental characteristics of how this Doppler method operates. Continuous-wave Doppler uses two transducer crystals: one continuously emits ultrasound waves while the other continuously receives the reflected signals. As a result, it captures reflections from all moving blood cells along the entire length of the beam, which can be quite broad. This means that while continuous-wave Doppler can accurately measure the velocity of blood flow, it cannot pinpoint the exact source of that flow data within a defined region or depth.

In contrast, other Doppler methods, such as pulsed-wave Doppler, allow for defined sampling volumes, giving clinicians the ability to assess flow in specific areas with finer resolution. The limitation of continuous-wave Doppler is particularly apparent in complex vascular systems where distinguishing between flow in different vessels or regions is critical for diagnosis and treatment planning.

This aspect of continuous-wave Doppler is what sets it apart and highlights the necessity for careful interpretation of its results in a clinical setting.