81. ULTRASOUND: APPLICATIONS Flashcards
1
Q
- What is Doppler Imaging used to measure?
A
- it is used to measure Blood Flow
2
Q
- What are the 3 major types of display Ultrasound signals?
A
- A-MODE
- B-MODE
- M-MODE
- this is also known as T-M MODE
3
Q
- What were the earliest displays that were used?
A
- A-mode devices
4
Q
- What does the A-mode display?
A
- it displays the voltage
- this is produced across the transducer on an
Oscilloscope
IT SHOWS A GRAPH:
- of intensity vs. distance
5
Q
- What is the A-Mode?
A
- this is the Amplitude Mode
THE AMPLITUDE OF THE REFLECTED SOUND
- is shown by the height of the vertical deflection on the
Oscilloscope
6
Q
- This is an example of a sound wave being transmitted through the side of the head.
What can be interpreted?
A
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
7
Q
- This is an example of a sound wave being transmitted through the side of the head.
What can be said about the distinct peaks?
A
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
8
Q
- What does A-Mode accurately determine?
A
- 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
9
Q
- What is B-Mode?
A
- this is Brightness Mode
- it is the pillar of ultrasound imaging
10
Q
- What does B-Mode provide?
A
- provides a real-time display
- this is also gray-scale
11
Q
- What do the variations in intensity and brightness indicate when we use B-Mode?
A
- they indicate reflected signals of different amplitudes
12
Q
- What do Brighter parts indicate when we use
B-Mode?
A
- they indicate larger reflections of sound
ON A BLACK BACKGROUND:
- the signals of greatest intensity are white
13
Q
- How does the absence of echoes come across in the images when we use B-Mode?
A
- the absence of echoes are black
- they also have intermediate intensities that appear as
grey
14
Q
- What does the Ultrasound Transducer (source) generate?
A
- it generates a short pulse
- this propagates through the body at the speed of
Sound of soft tissue (1540 m/s)
15
Q
- What happens when the shirt pulse reaches an interface?
(when looking at B-Mode signals)
A
- a small fraction of the pulse is reflected back to the
Transducer - this is known as the Echo Signal
16
Q
- What are the Echo Signals displayed as?
(when looking at B-Mode signals)
A
- they are displayed as a function of time
- this is called an “A” Scan
17
Q
- What happens when the Transducer is coupled to an arm?
A
- the signals are displayed as bright spots
- these represent the tomographic image of the tissue
- the image is called a “B” scan
18
Q
- Does this image make sense?
A
- yes
19
Q
- What is M-Mode?
A
- this is Motion Mode
- it provides a one-dimensional view of moving objects
over time
20
Q
- When is M-Mode extremely useful?
A
- it is extremely useful in Echocardiography
21
Q
- What does M-Mode display in Echocardiography?
A
- it displays the echo amplitude from the beating heart
- it includes the motion of the heart valves
22
Q
- Where is the Transducer positioned when we look at M-Modes in Echocardiography?
A
- it is positioned over the heart
- it is kept stationary
- it records the returning echoes over the same plane
23
Q
- What changes in Echocardiography scans?
A
- the position of the heart wall
- the position of the heart valves
- they change from one moment to the next
24
Q
- What is a limitation of M-Mode?
A
- the difficulty in achieving consistent and accurate
beam placements - this is with regards to the standard measurements and
calculations
25
Q
- Does this image make sense?
A
- yes
