VT Diagnostic Imaging Techniques 3

Question 1

On a spectral Doppler waveform, spectral broadening refers to:

Accepted Answer

Filling in of the spectral window due to turbulent or disturbed flow

Answer

Spectral broadening occurs when a range of velocities are present simultaneously, filling the normally clear spectral window, indicating disturbed or turbulent flow.

Question 2

Which parameter best distinguishes a high-resistance arterial waveform from a low-resistance one?

Accepted Answer

Pulsatility index

Answer

Pulsatility index (PI = [PSV − EDV] / mean velocity) quantifies resistance; high PI indicates high resistance (e.g., fasting mesenteric arteries), low PI indicates low resistance (e.g., renal arteries).

Question 3

Which artifact causes a vessel to appear duplicated when imaging near a highly reflective surface such as the pleura?

Accepted Answer

Mirror-image artifact

Answer

Mirror-image artifact occurs when the ultrasound beam reflects off a strong reflector (e.g., pleura), creating a duplicate image of the vessel on the other side of the reflector.

Question 4

Computed tomography angiography (CTA) of the lower extremities is performed with a scan direction that is:

Accepted Answer

Caudal to cranial to follow contrast bolus

Answer

For run-off CTA, scanning proceeds caudal to cranial (feet to pelvis) so the table moves counter to contrast flow, maximizing arterial enhancement throughout.

Question 5

In duplex imaging of the carotid artery, an increased internal carotid artery (ICA) to common carotid artery (CCA) PSV ratio above 2.0 suggests:

Accepted Answer

70% or greater stenosis

Answer

An ICA/CCA PSV ratio ≥ 2.0 correlates with hemodynamically significant stenosis of 70% or greater by the Society of Radiologists in Ultrasound consensus criteria.

(VT) Vascular Technician Certification Practice Test

(VT) Vascular Technician Certification Practice Test

VT Diagnostic Imaging Techniques 3