Comprehensive and Detailed Explanation From Exact Extract:
A larger sample volume collects Doppler signals from a wider region, which can include multiple velocities and noise. This leads to a broader spectrum (spectral broadening) and may introduce additional noise into the signal.
According to sonography instrumentation reference:
"Increasing the sample volume size increases the likelihood of including multiple velocity components and noise, resulting in spectral broadening and reduced spectral clarity." Therefore, the correct answer is B: Increased noise.
-

Comprehensive and Detailed Explanation From Exact Extract:
Sensitivity measures the test's ability to correctly identify true positives. It is calculated using the formula:
Sensitivity = True Positives / (True Positives + False Negatives)
From the table:
True Positives (TP) = 32 (Noninvasive test positive & Gold Standard positive) False Negatives (FN) = 3 (Noninvasive test negative but Gold Standard positive) Thus:
Sensitivity = 32 / (32 + 3)
Sensitivity = 32 / 35
According to sonography instrumentation reference:
"Sensitivity represents the proportion of actual positive cases correctly identified by the test." Therefore, the correct answer is B: 32/35.

Damping in a pulsed-wave transducer primarily affects the pulse duration. Damping refers to the process of reducing the vibration of the transducer crystal after the initial excitation. When damping is applied, it shortens the length of the ultrasound pulse by quickly reducing the vibration. This results in a shorter pulse duration, which is important for improving axial resolution. Damping does not directly affect the pulse repetition frequency, beam focus, or beam penetration, although it can have indirect effects on image quality and resolution. Reference:
ARDMS Sonography Principles and Instrumentation guidelines
"Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau

Comprehensive and Detailed Explanation From Exact Extract:
As ultrasound travels through tissue, it experiences attenuation - a reduction in signal amplitude due to absorption, scattering, and reflection. The deeper the reflector, the greater the attenuation. Therefore, the signal from reflector B (deeper structure) is weaker than from reflector A (shallower structure) primarily due to attenuation.
According to Principles and Instrumentation:
"Attenuation is the reduction in ultrasound beam strength as it propagates through tissue, resulting in decreased signal amplitude from deeper structures." Elasticity affects stiffness but not amplitude directly.
Propagation speed differences cause refraction or displacement, not amplitude changes.
Acoustic impedance differences cause reflection strength variations at interfaces but do not account for depth-dependent amplitude reduction.
Therefore, the correct answer is A: Attenuation.

Temporal resolution refers to the ability of the ultrasound system to distinguish events occurring closely in time. In color flow imaging, temporal resolution is affected by the frame rate, which can be increased by decreasing the width of the color field of view. This is because a narrower color field requires fewer scan lines to be processed, allowing for more frames to be captured per second.
Reference:
ARDMS Sonography Principles and Instrumentation guidelines
Edelman, S. K. (2017). Understanding Ultrasound Physics.