Color Doppler
Can color doppler be heard
No
What is the receiver responsible for
receiving and processing echo information
How many shades of gray in 4 bits
16
Flow that is its normal physiologic state is
Laminar / Parabolic
What angle do you get at a 90 degrees
Minimum doppler shift
What color is displayed with flow moving towards the transducer
Typically red, but whatever color is on the top of the color map
What are the 5 functions of the receiver
Amplification
Compensation
Compression
Demodulation
Rejection
What is the relationship between pixel density and spatial resolution
Directly
What factors produce resistance to flow
Viscosity
Friction
Inertia
What is the relationship between frequency and doppler shift
Diretly
What color represents a higher velocity
Brighter, lighter colors
What functions can be controlled by the sonographer
All except demodulation
What does using a higher persistence do to the image
Appears smoother
What does Poiseuille's predict
Volume flow rate
What is the difference between speed and velocity
Speed- rate of speed
Velocity- rate of speed and direction
What color is displayed that indicates turbulent flow on the variance map
Green
How can the sonographer compensate for attenuation
TGC's
What is fill in interpolation
filling technique of missing pixels
What is hemodynamics
Physical principles that govern the flow of blood
What is aliasing
Improper representation of a positive shift as a negative
Why is the angle not important in color doppler
It is qualitative information and does not provide exact velocities
What is rectification
Turs negative signals into positive signals
What are the benefits of Write zoom
Better spatial resolution
Image looks smoother
What is the most important pressure source
The heart
What information is given on the x axis and the y axis
x axis- time
y axis - velocity