Spectral broadening on Doppler is most strongly associated with which finding?

• A. Aneurysm
• B. Varicosity
• C. Stenosis
• D. Normal flow

Answer: (C)

Spectral broadening reflects nonlaminar, turbulent flow with a range of velocities within the sampled volume. In a normal artery, flow is largely laminar, giving a narrow, well-defined Doppler envelope. When a narrowing occurs, the velocity must rise to preserve flow, creating a jet that disturbs laminar flow and generates turbulence that extends downstream. This turbulence broadens the spectrum, and the extent often tracks the severity of the stenosis. So, the strongest association is stenosis. Aneurysm or varicosity can alter flow patterns, but they don’t produce the characteristic, focal spectral broadening seen with arterial stenosis; normal flow shows minimal broadening.