Color Flow Doppler in Echocardiography:
Color Doppler imaging displays blood flow direction and velocity within the heart. By convention:
🔴Red = Flow toward the transducer
🔵Blue = Flow away from the transducer
(BART rule: Blue Away, Red Toward)
The color velocity scale (shown on side) indicates flow speeds brighter hues = higher velocities.
The Nyquist limit (e.g., 69 cm/s here) defines the max velocity measurable without aliasing. Exceeding this limit causes aliasing: an apparent "color wraparound" mimicking reversed flow.
Limitations:
- Aliasing at high velocities
- Angle dependency: inaccurate if Doppler angle isn't aligned with flow
- Lower spatial resolution compared to 2D imaging
Clinical Significance:
Essential for detecting valve regurgitation, stenosis, septal defects, and abnormal shunts. Vital in assessing intracardiac flow patterns and diagnosing cardiac diseases early.
(Ref: Bulwer BE, Rivero JM. Echocardiography Pocket Guide, Jones & Bartlett, 2011, 2013)