ARDMS (American Registry for Diagnostic Medical Sonography) Practice Test

When would a sonographer NOT expect to see spectral broadening?

1. When measuring the velocity within a patent internal carotid artery

2. When sampling the velocity distal to a tight stenosis of the external carotid artery

3. When sampling the velocity at the bifurcation of the carotid artery

4. When sampling the velocity within a tight stenosis of the internal carotid artery

The correct answer is: When measuring the velocity within a patent internal carotid artery

Spectral broadening is a phenomenon seen in the Doppler waveform when there is a broad range of velocities present within the sample volume. In this context, when measuring the velocity within a patent internal carotid artery where the blood flow is normal and undisturbed, spectral broadening would not be expected. In the other scenarios mentioned: - When sampling the velocity distal to a tight stenosis of the external carotid artery or within a tight stenosis of the internal carotid artery, spectral broadening would be expected due to disturbed flow patterns and turbulence caused by the stenosis. - When sampling the velocity at the bifurcation of the carotid artery, spectral broadening may also be seen due to the change in flow dynamics at the branching point. Therefore, the correct answer is A because under normal conditions in a patent internal carotid artery, spectral broadening would not be observed.