ARDMS (American Registry for Diagnostic Medical Sonography) Practice Test

If a sonographer measures the peak systolic velocity (PSV) from the ICA and the spectral window appears filled in with blood moving in various directions, what does this indicate?

1. Spectral broadening

2. Patent ICA

3. The gain is set too high.

4. Laminar flow

The correct answer is: Spectral broadening

When a sonographer measures the peak systolic velocity (PSV) from the ICA and the spectral window appears filled in with blood moving in various directions, it indicates spectral broadening. Spectral broadening refers to the widening or filling in of the spectral window due to the presence of turbulent or disturbed flow within the vessel. This can occur in areas of stenosis or turbulence, resulting in a non-homogeneous flow pattern. In this case, the turbulent flow causes the red blood cells to move at different velocities, leading to a heterogeneous appearance in the spectral waveform. This is an important finding as it can indicate underlying pathology such as stenosis or occlusion in the vessel being evaluated. Option B (Patent ICA) is incorrect because a patent ICA would typically show a normal laminar flow pattern without spectral broadening. Option C (The gain is set too high) is incorrect because adjusting the gain settings would primarily affect the overall brightness of the image rather than the appearance of spectral broadening in the Doppler waveform. Option D (Laminar flow) is incorrect in this context as the presence of spectral broadening indicates disturbed or turbulent flow rather than the smooth, laminar flow seen in healthy vessels.