Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

imaging > Ultrasound > Flashcards

Ultrasound Flashcards

1
Q

What are sound waves measured in?

What is the frequency of ultrasounds?

A

Hertz

1-20 MHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Transducer (probe)
• how it works
• types

A

• Piezoelectric crystal

  • electrical energy –> sound energy
  • Echo returns as sound energy –> electrical energy (image)
  1. Linear Array
  2. Sector scanner
    • Curved Linear array
    • Phased array
    • Mechanical
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Attenuation

A

• Sound ↓ intensity as travels through tissue
- Scattered
- Absorbed
- Reflected
• Limited depth – can’t see past 30cm
• Amount of attenuation depends on frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Amount of attenuation depends on…?

A

Frequency

↑ frequency = ↑ attenuation

Time-Gain Compensator (TGC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Acoustic Impedance

A
  • Ability to impede sound
  • Depends on density & elasticity

• Varies slightly among most tissue
- Some reflection of sound & some transmission –> distinction btwn organ layers

• Different acoustic impedances produce reflective surfaces
- large variation –> ↑ sound waves reflected (air/bone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Frequency vs Patient depth

A

3 MHz – up to 35cm

5 MHz – up to 10 cm

7 MHz – up to 5cm

↑ frequency –> ↓ penetration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Resolution

• types

A

Ability to distinguish 2 adjacent objects

Lateral
• 2 objects next to each other

Axial
• 2 objects behind each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is important to determine lateral resolution?

A

Focal zone

– higher frequency = narrower focal zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Modalities of Ultrasound?

A
  1. A-mode
  2. B-mode
  3. M-mode
  4. Doppler- mode
    • Spectral
    • Color
    • Power
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe A-mode

A

• Spikes
- where precise length & depth measurements needed
–”ophthalmology”

• Some machines still have A–mode capability, but not used much anymore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe B-mode

A

Reflected echoes displayed as Gray dots
- can be given diff colors

• Black = No echoes
- anechoic
• White = LOTS of echoes
- hyperechoic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe M-mode

A

Motion mode
• Echocardiography

– creates a section thru the heart to look at wall thickness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe Doppler-mode

What can it tell you?

A

• Sounds reflected @ diff frequency from moving objects

  1. Quantify velocity
  2. Direction of flow
  3. Is the structure vascularized?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe Spectral Doppler mode

A
  1. Pulsed Wave doppler
    - same crystal
    - used w/ B-mode (duplex doppler)
    (++) identifies specific area
    (–) Limited velocity capability
  2. Continuous wave doppler
    - 2 crystals
    (++) Measures higher velocity = tells max velocity
    (–) measures all doppler shifts along the path of the sound wave
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

On a color doppler, what indicates the direction of flow?

A

Blue - Away

Red - Towards

BART

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe Power Doppler

A

aka Angio Mode

  • No direction or velocity
  • Tells you intensity of flow

Good for:

    • Low Flow States
    • Parenchymal perfusion
    • Small vessels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the 8 features that should be described when doing an echo

A
  1. Size
  2. Shape
  3. Number
  4. Location
  5. Margination
  6. Echogenicity
  7. Echotexture
  8. Through transmission
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What causes Hyperechoic image?

A

High intensity returning echoes

• Due to big acoustic impedance mismatch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does it mean to be Isoechoic?

A

Same number of returning echoes as adjacent tissue
• looks the same as surrounding tissue
• needs to be compared to something.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

List 3 possible “through transmissions” seen in ultrasound

A
  1. Shadow
  2. Enhancement
  3. Reverberation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Image description of Fluids

A
  • Anechoic
  • Cellular / crystalline content
  • Mobile
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Image description of Gas

A

• Free gas

  • hyperechoic w/ reverberation artifact
  • Cast “dirty shadows”

• Lungs
- Curtain sign

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Image description of Mineral

A

Hyperechoic w/ acoustic shadow
• Bone, calcification, calculi

Note: Cartilage = anechoic

24
Q

Image description of muscle

A

Striated pattern

25
Q

Image description of Metal Foreign Body

A

Hyperechoic w/ comet tail artifact

26
Q

Image description of Wooden Foreign body

A

Hyperechoic w/ acoustic shadowing

27
Q

Reasons for artifact

A
  1. Sound beam properties
  2. Transducer qualities
  3. Computer assumption
    • sound travels straight @ 1240 m/sec
  4. Machine adjustments
  5. Operator technique
28
Q

Useful artifacts

A
  1. Acoustic Shadow
  2. Acoustic Enhancement
  3. Edge shadowing
  4. Reverberation
  5. Ring down effect
  6. Comet-tail
  7. Mirror image
  8. Slice thickness
29
Q

Confusing Artifacts

A
  1. Propagation speed error
  2. Side lobe
  3. Operator induced
30
Q

Acoustic shadow

A

• Interface absorbs or reflects all sound
–> anechoic area beyond it.

• ex. FB w/in intestinal loop

31
Q

Acoustic enhancement

A

• Fluid structures w/ homogenous acoustic impedance attenuate less sound than surrounding structure
–> ↑ beam strength beyond this structure compared to adj tissue

32
Q

Edge shadowing

A

Round structure (ex. retained testes)

  • -> Refraction + Reflection
  • -> Narrow shadows on edges

Refraction
• differing speeds of sound in structure compared to surrounding tissue

Reflection
• Angled incident beam

33
Q

Reverberation artifact

A

Interface reflects all sound

  • -> reflected back into body by transducer
  • -> bouncing back and forth
  • -> multiple hyperechoic equidistant lines

Ex-?

34
Q

Ringdown artifact

A

Type of Reverberation artifact

• Bugle-shaped fluid trapped btwn 2 layers of gas
• continuous sound wave back to transducer
–> Solid echogenic streak or closely spaced echogenic lines

Ex ??

35
Q

Comet tail artifact

A

Big Z mismatch
–> regular reverberations
+ Internal reverberations
–> solid echogenic streak

Ex. Metallic objects

36
Q

Mirror image artifact

A

hyperechoic, curved surface –> Reflection of Initial sound further into body

  • -> Time delay of initial waves
  • -> object appears further away

Qualities surface needs to have:

  1. Lg difference in acoustic impedance
  2. Reflective surface
37
Q

Slice thickness

??

A

Curved anechoic structures adjacent to tissue
–> appears like sediment

Ex. Fat around bladder looks like sediment = Pseduosludge

38
Q

Pros & cons of positioning patient in Lateral Recumbency for ultrasound

A

Pros
• Animal likely to lie quietly
• Less tech assistance

Cons
• Animal must be flipped
• Organs change positions

39
Q

Pros & cons of positioning patient in Dorsal Recumbency for ultrasound

A

Pros
• 1 position for entire scan
• organs dont shift

Cons
• Animals don’t usually like being on their back
• post-nasal drip –> sneezing

40
Q

Explain orientation of a Lateral image

A 
Cranial = left screen
Caudal = right screen
Ventral = Top screen
Dorsal = bottom screen
41
Q

Explain orientation of a Transverse image

A 
Right = Left screen
Left = Right screen
Ventral = top screen
Dorsal = bottom screen
42
Q

Describe how to scan for Liver

A 
• Cranial abdomen
• Lateral recumb 
   - subcostal
   - intercostal 
• Dorsal recumb
   - subxiphoid
   - intercostal
43
Q

Normal appearance of Liver on ultrasound

A

• Texture:
- homogenous & course

• Echogenicity:

  • Hypoechoic to spleen
  • Iso/hypoechoic to kidney

• Vessels

  1. Portal vein
    • anechoic tube w/ echogenic walls
  2. Hepatic vein
    • Similar but less echogenic walls (blend w/ parenchyma)

• Gall bladder = anechoic

44
Q

If you see a “kiwi” shape in the liver, what is the most likely ddx?

A

Gall bladder mucocele

45
Q

Describe how to scan for Kidneys

A 
• Retro-peritoneal space
• Mid/cranial abdomen
   - R = more cranial
   - L = caudal to the last rib
• 2+ imaging planes
46
Q

Normal appearance of Kidney on Ultrasound

A

Cortex
• Homogenous
• Fine echotexture

Medulla
• Uniform
• hypoechoic relative to cortex

Hilar fat
Interlobar /arcuate vessels
• Hyperechoic

47
Q

Normal appearance of Urinary Bladder on Ultrasound

A

Caudoventral abdomen
• usually anechoic fluid
• Thickness <3mm

48
Q

Normal appearance of Spleen on Ultrasound

A
  • Homogenous
  • Fine echotexture

Hyperechoic to liver & cortex of kidney

49
Q

Describe how to scan for the Spleen

A 
Mostly on LEFT
• Head (fixed)
    - cranial to L Kidney
    - dorsolateral to fundus
• Body/tail ("Wanderer")
    - Left body wall
    - crossing ventrally toward R
50
Q

Layers of stomach wall

A 
5 layers
• Mucosal surface
     - hyper
• Mucosa
     - hypo
     - usually thickest
• Submucosa
     - hyper
• Muscularis
    - hypo
• Serosa
     - hyper
51
Q

Location of small bowel on ultrasound

A

Cranial-ventral abdomen
• Duodenum
- along R body wall from pyloric antrum

52
Q

Normal thickness of Small Bowel on Ultrasound

A

2-4 mm

• divided into 5 layers

53
Q

Describe how to scan for the Colon

A

Starts @ R cranial abdomen

  • -> crosses body to Left
  • -> caudally to pelvic inlet
54
Q

Normal thickness & appearance of the Colon

A

1-2 mm thick
• no wall layers seen

Very echogenic
- due to gas and feces

55
Q

Location of Uterus on ultrasound

A

Isoechoic small tubular structure

btwn bladder & descending colon

56
Q

Normal vs abnormal Thoracic cavity ultrasound image

A

Normal should see nothing

Pleural effusion
- can see the lung lobes

imaging (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions