Spectral broadening indicates which type of flow?

• A. Turbulent flow
• B. High resistance flow
• C. Slow heart rate
• D. Tachycardia

Answer: (A)

Spectral broadening reflects a wide range of velocities within the sampled tissue or vessel. In laminar flow, velocities are evenly distributed across the cross-section, so the Doppler spectrum is narrow and well-defined. When flow becomes turbulent, chaotic eddies create many different velocity vectors at once, spreading Doppler frequencies over a broad range. This broad, smeared spectrum is a hallmark of turbulent flow and is often seen where flow is disturbed, such as near a stenosis or other obstruction. The other options don’t inherently produce this velocity spread: high resistance affects waveform shape rather than velocity distribution; slow heart rate or tachycardia change timing and peak velocity rather than the range of velocities within the sample volume.