SPI Exam Dumps : Sonography Principles and Instrumentation

According to Poiseuille's law, the flow rate of a fluid through a vessel is directly proportional to the fourth power of the vessel's radius. Therefore, a small change in the radius of the vessel has a much larger effect on blood flow compared to changes in pressure gradient, length of the vessel, or viscosity of the fluid.

ARDMS Sonography Principles and Instrumentation guidelines

Poiseuille's law in medical physics and hemodynamics literature.

Compression in ultrasound imaging adjusts the range of grayscale displayed, affecting the contrast resolution.

This function allows sonographers to enhance the differentiation between structures of varying echogenicities.

By modifying the contrast resolution, sonographers can better visualize subtle differences in tissue composition and improve the diagnostic quality of the images.

Increasing contrast resolution is particularly important in differentiating between fluid-filled cysts and solid masses.References:

ARDMS Sonography Principles and Instrumentation guidelines on image processing and contrast resolution.

Aliasing in color Doppler occurs when the velocity of blood flow exceeds the Nyquist limit, which is half the PRF. To reduce aliasing, the PRF must be increased. This raises the Nyquist limit, allowing higher velocities to be measured without wrapping around the baseline. Increasing PRF reduces the occurrence of aliasing artifacts by expanding the range of detectable velocities before aliasing occurs.