Doppler Mode

Doppler assess a frequency change in the returning ultrasound signal. If a signal impacts a moving object; it returns to the transducer at a different frequency.

  • Movement towards the transducer INCREASES the frequency of the return signal
  • Movement away from the transducer DECREASES the frequency of the return signal
  • The amount of Doppler shift is related to the velocity of movement (higher velocity flow; more Doppler shift)
  • In “regular” Doppler, the moving object is blood flowing. However, in tissue Doppler Imaging the moving object is the tissue itself

Pulsed Wave Doppler (PWD) (Figure 1)

  • Pulsed signal allows listening at a specific point. However, it will alias at high flows (Figure 2)
  • A grey value (white to black) is assigned to the Doppler shift
  • Along a Time (sec) X-axis vs. Distance (cm, or m) Y-axis to display velocity (cm/sec)
  • X-axis is called the baseline
  • Used to assess stroke volume and hepatic and portal venous flow (Figure 1)

Continuous Wave Doppler (CWD) (Figure 3)

  • One crystal continuously sends and another on one receives the signal
  • It listens along the entire cursor, not a specific spot, and it does not alias.
  • It measures high flow jets
  • A grey value (white to black) is assigned to the Doppler shift
  • Displayed on distance vs time axis
  • Used to assess for elevated systolic pulmonary artery pressure, and to grade/assess aortic stenosis (Figure 3)

Color Flow Doppler (CFD) and Duplex Doppler (Figure 4)

  • Type of pulsed wave Doppler (will alias at high flows)
  • A color value is assigned to positive and negative Doppler shift
  • The CFD is overlaid onto a 2D image to create Duplex Doppler
  • Used to identify location of normal blood flow, identify pathologic blood flow (i.e. ventricular septal defect), and assess valvular function

Tissue Doppler Imaging (TDI) (Figure 5)

  • Type of pulsed wave Doppler
  • Measures tissue movement
  • Most commonly the left ventricle at the mitral annulus
  • Used to asses diastolic function


In color Doppler, by convention flow towards the transducer is red, flow away is blue. This is not related to arterial or venous flow


Figure 1 - Pulsed Wave Doppler

Figure 2 - Aliasing at high flows

Figure 3 - Continuous Wave Doppler

Figure 4 - Color Flow Doppler

Figure 5 - Tissue Doppler


Chan, Vincent, and Anahi Perlas. “Basics of ultrasound imaging.” Atlas of ultrasound-guided procedures in interventional pain management. Springer, New York, NY, 2011. 13-19.