ARDMS SPI Dumps

The quality factor (Q-factor) is a dimensionless parameter that describes the efficiency of the transducer in terms of bandwidth and operating frequency. It is defined as the ratio of the operating frequency to the bandwidth. A higher Q-factor indicates a narrower bandwidth relative to the operating frequency, resulting in more precise frequency characteristics but potentially reduced axial resolution. Conversely, a lower Q-factor indicates a broader bandwidth, which improves axial resolution but may result in less precise frequency characteristics.

References:

ARDMS Sonography Principles & Instrumentation Guidelines

Kremkau FW. Sonography Principles and Instruments. 9th ed. Philadelphia, PA: Elsevier; 2016.

In a variance mode color map, the upper right side typically indicates higher velocity and turbulent flow with a positive Doppler shift. Variance mode maps are designed to display not only the mean velocity and direction of blood flow but also the presence of turbulence. The color green is often used in the upper right quadrant to represent areas of turbulence with positive Doppler shifts, which occur when the blood flow is moving towards the transducer at higher velocities and with increased chaotic motion. References:

ARDMS Sonography Principles and Instrumentation guidelines

"Diagnostic Ultrasound: Physics and Equipment" by Peter Hoskins, Kevin Martin, Abigail Thrush

The aperture of a transducer is the active area that emits and receives the ultrasound waves. In a linear array transducer, increasing the aperture (using more elements for transmission and reception) results in a deeper focus because the beam is more tightly focused over a longer distance. This improves lateral resolution at greater depths, as the ultrasound beam maintains a narrower width for a longer distance. It allows for better imaging of deeper structures without sacrificing resolution.

References:

American Registry for Diagnostic Medical Sonography (ARDMS). Sonography Principles and Instrumentation (SPI) Examination Review Guide.