81. ULTRASOUND: APPLICATIONS

Question 1

1. What is Doppler Imaging used to measure?

Answer 1

• it is used to measure Blood Flow

Question 2

2. What are the 3 major types of display Ultrasound signals?

Answer 2

1. A-MODE
2. B-MODE
3. M-MODE
   • this is also known as T-M MODE

Question 3

3. What were the earliest displays that were used?

Answer 3

• A-mode devices

Question 4

4. What does the A-mode display?

Answer 4

• it displays the voltage
• this is produced across the transducer on an
  Oscilloscope

IT SHOWS A GRAPH:
- of intensity vs. distance

Question 5

5. What is the A-Mode?

Answer 5

• this is the Amplitude Mode

THE AMPLITUDE OF THE REFLECTED SOUND
- is shown by the height of the vertical deflection on the
Oscilloscope

Question 6

6. This is an example of a sound wave being transmitted through the side of the head.
   What can be interpreted?

Answer 6

THE REFLECTED BEAM IS A LINE:
- it has 3 distinct peaks
- these are known as the Amplitudes
- they form where the sound is reflected off of 3 hard
formations

Question 7

7. This is an example of a sound wave being transmitted through the side of the head.
   What can be said about the distinct peaks?

Answer 7

THE FIRST PEAK:
- is the skull closest to the Transducer

THE SECOND PEAK:
- is the midline structure in the brain
- this is known as Flax Cerebril

THE THIRD PEAK:
- is formed from the skull bone on the opposite side of
the head

Question 8

8. What does A-Mode accurately determine?

Answer 8

• it accurately determines the depth of the reflectors
• this can show the width of the organs

IT IS USED EXTENSIVELY:
- in ophthalmology
- this is where accurate measurements are important

Question 9

9. What is B-Mode?

Answer 9

• this is Brightness Mode
• it is the pillar of ultrasound imaging

Question 10

10. What does B-Mode provide?

Answer 10

• provides a real-time display
• this is also gray-scale

Question 11

11. What do the variations in intensity and brightness indicate when we use B-Mode?

Answer 11

• they indicate reflected signals of different amplitudes

Question 12

12. What do Brighter parts indicate when we use
    B-Mode?

Answer 12

• they indicate larger reflections of sound

ON A BLACK BACKGROUND:
- the signals of greatest intensity are white

Question 13

13. How does the absence of echoes come across in the images when we use B-Mode?

Answer 13

• the absence of echoes are black
• they also have intermediate intensities that appear as
  grey

Question 14

14. What does the Ultrasound Transducer (source) generate?

Answer 14

• it generates a short pulse
• this propagates through the body at the speed of
  Sound of soft tissue (1540 m/s)

Question 15

15. What happens when the shirt pulse reaches an interface?
    (when looking at B-Mode signals)

Answer 15

• a small fraction of the pulse is reflected back to the
  Transducer
• this is known as the Echo Signal

Question 16

16. What are the Echo Signals displayed as?
    (when looking at B-Mode signals)

Answer 16

• they are displayed as a function of time
• this is called an “A” Scan

Question 17

17. What happens when the Transducer is coupled to an arm?

Answer 17

• the signals are displayed as bright spots
• these represent the tomographic image of the tissue
• the image is called a “B” scan

Question 18

18. Does this image make sense?

Answer 18

• yes

Question 19

19. What is M-Mode?

Answer 19

• this is Motion Mode
• it provides a one-dimensional view of moving objects
  over time

Question 20

20. When is M-Mode extremely useful?

Answer 20

• it is extremely useful in Echocardiography

Question 21

21. What does M-Mode display in Echocardiography?

Answer 21

• it displays the echo amplitude from the beating heart
• it includes the motion of the heart valves

Question 22

22. Where is the Transducer positioned when we look at M-Modes in Echocardiography?

Answer 22

• it is positioned over the heart
• it is kept stationary
• it records the returning echoes over the same plane

Question 23

23. What changes in Echocardiography scans?

Answer 23

• the position of the heart wall
• the position of the heart valves
• they change from one moment to the next

Question 24

24. What is a limitation of M-Mode?

Answer 24

• the difficulty in achieving consistent and accurate
  beam placements
• this is with regards to the standard measurements and
  calculations

Question 25

25. Does this image make sense?

Answer 25

• yes