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What are common color maps used in Doppler imaging?
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Common color maps in Doppler imaging are variance and velocity.
Define the frame rate necessary for the human eye to perceive without flicker.
The frame rate must be at least 30 frames per second for the human eye to perceive without flicker.
What modification should be made to enhance deep flow visibility in color Doppler?
Decrease the ultrasound frequency to enhance deep flow visibility in color Doppler.
How can frame rate be calculated in terms of time to create an image?
Frame rate is the reciprocal of the time taken to create an image; for example, 1/20th of a second results in a frame rate of 20 Hz.
What is Reynolds number and its importance in ultrasound?
Reynolds number predicts the presence of turbulent flow in the ultrasound image.
What effect does line density have on an ultrasound image?
Line density refers to the number of scan lines per centimeter and affects image resolution.
What is the limitation of Power Doppler in ultrasound imaging?
Power Doppler cannot determine the direction of blood flow; it only indicates the presence of flow.
What should a sonographer do if a patient refuses an examination?
The sonographer should immediately stop the examination if the patient refuses.
What is the implication of using binary numbers in ultrasound imaging systems?
Binary numbers, consisting of ones and zeros, are fundamental for digital processing in imaging systems.
What is the focus in terms of ultrasound beam characteristics?
The focus is the narrowest part of the ultrasound beam.
Describe an acoustic speckle and its cause.
Acoustic speckle is a noise artifact caused by interference of small amplitude sound waves.
How can axial resolution be improved in ultrasound imaging?
Axial resolution can be improved by increasing the bandwidth.
How can temporal resolution be maximized in ultrasound imaging?
Temporal resolution is maximized by decreasing depth and reducing the number of scan lines.
How does frequency shift relate to the Doppler equation in ultrasound?
Frequency shift increases with higher transmit frequency according to the Doppler equation.
Why are 4 bits required for displaying 15 different shades of gray?
4 bits are required because 2^4 = 16, which is sufficient to encode 15 different shades.
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