What are the 5 components of ultrasound imaging?
Pulser, transducer, receiver, memory, display
and the 6th one that coordinates the other?
Master synchronizer
What is the goal of the complements?
To image
How many PZT elements does a continuous wave use?
2
Which component controls PRF, PRF, amplitude of pulse, frequency for CW, & firing pattern for array transducer?
Pluse wave
What is the rule concerning power and gain?
Minimize power and max gain
Another name for acoustic power?
output power, transmit, outgain
Which components converts ultrasound to electrical voltage and sends it to the receiver?
crystal aka transducer
In correct order, what are the 5 functions of the receiver?
Which receiver function for the user have NO control over?
Demodulation
Which receiver function makes up for echo information that is decreased due to attenuation of sound?
Compensation
Which receiver function squeezes the signal amplitude into a narrower range?
compression
Which receiver function eliminates the smallest amplitude voltages?
Rejection
Which receiver function boosts the signal?
Amplification
What receiver function handles smoothing and rectification?
Demodulation
What does smoothing do?
avg out the signal
What does rectification do?
Turn neg signal to positive
Between higher and lower dynamic ranges which has the higher contrast?
Lower
What helps to reduce noise?
Rejection
What 2 functions control the brightness of the image on screen?
gain, power
Another name for the scan converter is
Memory
Random acess memory
digital
silicon wafer
analog
8 bits is equal to 1
Byte
What are the two possible bits
0=off and 1=on
What is the term pixel short for
picture element
What happens to spatial resolution if the number of pixels increase
Increases
A 5 bit system will have how many shades of grey
2^5
On a newer machine, like a logic 9, are TGC’s pre or post processing?
Both
On a logic 9, is gain pre or post processing?
Both
On a logic 9, is write zoom pre or post processing?
Pre
On logic 9, is labeling pre or post processing?
Both
On a logic 9, are the calipers pre or post processing?
Post
On a logic 9, is depth pre or post processing?
pre
What does the edge button do?
smooth out the edge
Low persistence us for__ moving structures like the ______
fast, heart
Frame averaging is also known as ________
persistence
What is the filling in technique called the fills in a missing pixels brightness based on average brightness of the surrounding pixels?
Interpolation
What another name for an old school tv monitor?
CRT (cather ray tube)
Electronic beam direction in fixed pattern of horizontal sweeps across screen (left to right and top to bottom) what is the pattern called?
Raster scan
A bean if electronics is directed at a light emitting phosphor on a screen and causes the screen to change frequency?
False
In diagnostic imaging, how many frames per second for a flicker free image?
30
What kind of display writes the odds lines and the evn lines second?
Innerlaced
What kind of display wires the line in sequences?
non-interlaced
What is the difference between HD and Standard display monitors?
Better Special resolution, more lines more pixles
What adjusts the screen brightness level?
brightness
What adjusts the range of echo brightness to darkness (black and white)
contrast
What kind of printer uses heat sensitive paper to preserve the image and may degrade with time?
thermo printer
PACS is an acronym for
picture archiving and communication system
When Frame Per Sec increase in temporal resolution better or worse?
better
Name 4 factors competing for time
SMIL: sector size, multiple focal zone, image depth and line density
What 2. things are needed for blood to flow?
Path to travel and pressure of gradient
In the body pressure is created by what?
Heart, gravity, calf( second heart)
What variable do we use for flow volume rate?
Q
Resistance to motion because of two moving objects touching each other is?
Friction
The fluid’s thickness or stickiness is?
Viscocity
The tendency of an object to maintain its “status quo” is
enurtia
What kind of flow do we need to use poiseuille’s equation?
laminar
If you increase resistance
flow rate decreaes
Define each variable
P1, P2= pressure gradiant, prox and dist.
r=radius
L=length
N= viscosity
Write poiseuille equation and what does it predict?
Q=P/R; it predicts laminar flow(parabolic is another name)
Diaphragm descends and lower extremity venous flow decreases
inspiration
The weight of the column of blood from the heart to the point where the pressure is measured is
Hydrostatic pressure( it’s just gravity)
At how many frames can a human eye detect?
<16
What regulates PACS and what it is overall good for?
DICOM and teleradiology
When we use a doppler instrument in US, what is the source of sound, the receiver of sound, and the reflector of sound?
Transducer, transducer and red blood cells
Write the 2 equations we have for the doppler shift( short)
Reflected frequency- Transmit frequency
In US, what does a negative doppler shift mean? positive shift?
Moving away from source; moving towards
What is the difference between speed and velocity?
rate at which an object is moving along a path, while velocity is the rate and direction of an object's movement.
Cosine of 90 degrees=
Cosine of 0 degrees=
Cosine of 60 degrees=
Cosine of 180 degrees=
0 no shit
+1
1/2
-1 or 1
The max doppler shift will occur at what degree
0 or 180
No shift will occur at what degree
90
How do you know if you have positive shift on a color doppler and pulse doppler?
What is a disadvantage of CONTINUOUS WAVE?
Range ambiguity
What’s a disadvantage of pulsed wave?
aliasing
What is another US Doppler instrument not already mentioned?
Color doppler, power doppler
What is the nyquist limit?
1/2 PRF; is limit at which alising will occur
What is aliasing
Machine will represent positive shift as negative shift
How do you know if you have a positive shift on a color doppler and pulse doppler?
What are the 5 ways to eliminate aliasing?
Chose shallower sampling depth
increase velocity scale
adjust baseline shift
Choose lower frequency transducer
Use CW instead
What’s the name of the complex mathematical process analyzes the signal and provides quantitative data on different reflector velocities making up the signal?
FFT
Name 3 types information PULSED DOPPLER can provide:
Velocity of flow
direction of flow
range of frequencies
How to calculate Pulsatility and Resistivity Index
PI= max velocity-min velocity/ mean velocity
RI= Max-min/Max
Axes table
What is superimposed on a two dimensional grayscale image presenting flow information?
Color doppler
If nothing has been inverted, what does the color red represent?
Positive shift
The color blue?
Negative shift
What refers to the number of ultrasound pulses per line of color?
Packet size
Which packet size has better temporal resolution?
smaller
Scan converter
aka memory
What is a bit? 8 bits is__
A binary #, One byte
(0,1,0,0,1,0)
6 bit
Image is made of pixels, and pixels are bit
True
The more pixles=
the better the spacial resolution
More bits=
More shades of gray, more contrast
As more pixel is present
Pixel density increases
PREPROCESSING
PREPROCESSOR ALLOWS CHANGE, ALTERATION, OR MANIPULATION OF ECHO SIGNALS PRIOR TO BEING STORED IN COMPUTER MEMORY
Low persistence for fast moving structures (heart)
High persistence for slow moving structure (testes)
true
PERSISTENCE
A TYPE OF FRAME AVERAGING USED TO MAKE THE IMAGE APPEAR SMOOTHER
fill in trepollation
If there is pixel missing from a image the machine avg out all the surrounding pixel to fill in the image