ARDMS (American Registry for Diagnostic Medical Sonography) Practice Test

When a vibrating string or fluid pump is used for system testing, which parameter is being evaluated?

1. Contrast resolution

2. Doppler velocities

3. Grayscale sensitivity

4. Dead zone

The correct answer is: Doppler velocities

When a vibrating string or fluid pump is used for system testing, the parameter being evaluated is Doppler velocities. Doppler ultrasound is a technique used to assess the velocity of blood flow or movement of tissues within the body. By analyzing the frequencies of the echoes produced when sound waves interact with moving blood or tissue, Doppler ultrasound can provide valuable information about the direction and speed of flow. By testing the system with a vibrating string or fluid pump, sonographers can assess how well the system is able to accurately detect and measure these Doppler velocities. Contrast resolution refers to the ability of the system to distinguish between different shades of gray, which is not the parameter being evaluated in this scenario. Grayscale sensitivity is related to the system's ability to display different shades of gray, and the dead zone refers to the region near the transducer where accurate imaging is not possible due to artifact formation.