Study guide 3

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?

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