Final answer:
A Doppler ultrasound is particularly useful for confirming blockage in the case of an arterial ulcer, as it reveals the blood flow and velocity in arteries, which is critical for diagnosing arterial blockages.
Step-by-step explanation:
You should perform a Doppler ultrasound to confirm blockage in the case of an arterial ulcer. An arterial ulcer is caused by inadequate perfusion of blood to the tissue, commonly due to arterial blockage. A Doppler ultrasound will help determine the speed and volume of blood flow through arteries, revealing areas where blockage may be present and confirming if an arterial ulcer is indeed due to arterial insufficiency.
In a partially constricted artery, one would expect the blood speed to be greatest at or near the constriction. The two distinct causes of higher resistance in the constriction are the reduced cross-sectional area through which the blood must pass and the potential for increased turbulence as blood flows through the narrowed region.
Using Doppler-shifted ultrasonic imaging, medical professionals can visually assess the change in blood speed, depicted with colors: red indicating the highest velocities and blue the lowest, as depicted in FIGURE 17.49 by Arning C, Grzyska U.