11/15 Quiz Flashcards
In A-Mode the X- Axis represents:
In A-Mode the Y-Axis represents:
Depth
Amplitude
In B-Mode the X-Axis represents:
In B-Mode the Z-Axis Represents:
Depth
Amplitude
Your standard series of dots with varied brightness
B-Mode
In M-Mode the X-Axis represents
In M-Mode the Y-Axis represents
Time
Depth
CRT stands for
Cathode Ray Tube
Cathode also known as
Electron gun
What is an important component of CRT
Anode or focusing coil
The focusing coil of the CRT have what type of charge applied which then eliminates
Postitive charge
Eliminates stray electrons
Magnification is used to improve
Means that a portion of the image is
Visualization of a portion of an image
Enlarged to fill the entire screen
Selection of portion that is magnified
ROI - Region of interest
This is performed while the data is being read in, before stage in the scan converter
Write Magnification
What are the steps of write magnification
Scan
Convert A to D and store data in scan converter
Identify ROI - System discard data in scan converter
System rescans only region of interest and writes new data
Characteristics of Write Magnification:
Image used to -
Number of pixels or scan lines -
Increased number of
Used to identify ROI is discarded
In ROI image is greater than that of the ROI portion in original image
Pixels in ROI improves spatial resolution
Is performed after the image is stored in the scan converter
Read magnification
Steps for read magnification
Scan patient
Convert A to D; Store data in scan converter
Sonographer select ROI; System reads and displays only that info
Characteristics of read info:
Number of pixels in magnified images -
Spatial resolution -
Can be done on
Same as original
Does not change & pixels are larger in zoomed in image than original
Frozen image
What is shown to the sonographer by instrument
Display
What is recorded by the instrument for future reference
Storage
Draw diagram of CRT
Image on Ch. 6 Review
List the 4 characteristics of imaging
Normal incidence
High f - Improves resolution
PW Only
Min 1 crystal
List 4 Characteristics of Doppler
0-180
Low f - Avoids aliasing
CW & PW
Min 1 Pulse; 2 Continuous
Aliasing is increased with what 3 things
Faster blood flow velocity
Higher f transducers
Deep gates (Low PRF)
What are the 5 ways to clean up aliasing
Adjust scale max
Select new window with shallow sample volume
Use low f transducer
Use baseline shift
Use CW Doppler
When cleaning up aliasing with adjusting the scale to its max what does that cause
Increase Nyquist limit
When cleaning up aliasing with selecting a new window with shallow sample volume what does that cause
Increase Nyquist limit
When cleaning up aliasing with using a lower frequency transducer what does that cause
Decreases Doppler shift
When cleaning up aliasing with using a baseline shift what does that cause
Display looks better
When cleaning up aliasing with using CW Doppler what does that cause
No aliasing but range ambiguity
What are the equations for Doppler shift
DS = Reflected frequency - Transmitted frequency
fD = 2fovcos0/c
A-Mode has no
Image
What is A-Mode
Amplitude Mode
When using A-Mode when you have a higher amplitude what does that cause
Lightening of the image
What is B-Mode
Brightness mode
What mode do you use in general U/S
B-Mode
What type of image does B-Mode produce
3-D
What is M-Mode
Motion Mode
What mode is used in echo U/S
M-Mode
M-Mode makes
Wave forms
In the Doppler shift drawing (in your notes) which has the greatest positive shift?
A, B, C, D, or E
A
In the Doppler shift drawing (in your notes) which has the greatest frequency
A, B, C, D, or E
A & B
In the Doppler shift drawing (in your notes) which has the same frequency as the transducer
A, B, C, D, or E
C
In the Doppler shift drawing (in your notes) which has the lower frequency
A, B, C, D, or E
D & E
In the Doppler shift drawing (in your notes) which has the greatest negative Doppler shift
A, B, C, D, or E
E
With binary number which side do you start with ?
Right
How many shades of gray are there that the human eye can distinguish
256
What does SOG stand for
Shades of gray
If the computer gives you IOII what is the SOG
2^0 + 2^1 + 2^3
1 + 2 + 8 = 11th SOG
Draw an example of B-Mode
Sag Right Liver w/ Kidney Interface Image
Draw an example of M-Mode
Image box with pulse waves under for HR
The phosphors in the CRT diagram does what
Activated GRB generates color
The focusing coil in the CRT diagram is a ____ anode does what
Positice anode
Collects stray electrons
