Which feature is present in a Doppler spectral waveform?

Which feature is present in a Doppler spectral waveform?

• A. Spectral broadening
• B. Narrow velocity range
• C. Aliasing
• D. Mirror imaging

Answer: (A)

A Doppler spectral waveform shows the distribution of blood velocities within the sampled gate. When flow is smooth and uniform, most red blood cells share a similar velocity, producing a relatively narrow spectrum. If the flow is disturbed or turbulent, or if multiple velocity components coexist within the gate (such as downstream from a narrowing or near a bifurcation), a wide range of velocities is present, causing the spectrum to smear or broaden. This spectral broadening is the sign that a broader distribution of speeds exists inside the gate. Aliasing would show up as a wrap of high-velocity portions into the opposite side of the display, not as a broadening of the spectrum itself. Mirror imaging is an artifact where a duplicate appears on the opposite side or as a misleading copy of the waveform, not a normal feature of the Doppler spectrum. A very narrow velocity range would indicate the opposite of broadening, i.e., highly uniform laminar flow.

A Doppler spectral waveform shows the distribution of blood velocities within the sampled gate. When flow is smooth and uniform, most red blood cells share a similar velocity, producing a relatively narrow spectrum. If the flow is disturbed or turbulent, or if multiple velocity components coexist within the gate (such as downstream from a narrowing or near a bifurcation), a wide range of velocities is present, causing the spectrum to smear or broaden. This spectral broadening is the sign that a broader distribution of speeds exists inside the gate.

Aliasing would show up as a wrap of high-velocity portions into the opposite side of the display, not as a broadening of the spectrum itself. Mirror imaging is an artifact where a duplicate appears on the opposite side or as a misleading copy of the waveform, not a normal feature of the Doppler spectrum. A very narrow velocity range would indicate the opposite of broadening, i.e., highly uniform laminar flow.