Basics of Ultrasound Imaging Flashcards
1
Q
Describe ultrasound
A
- Portable, non-zoning, low cost = widely available
- Point of care/bedside
- 2-Dimensional slices of internal structures: transverse, sagittal, coronal, oblique
- Real time image capture
2
Q
Describe the production of an ultrasound image
A
- Transducer in US probe emits high-frequency sound pulses
- Pulses travel across body surface into patient’s body
- Encounter tissues with varying acoustic properties
- Some sound energy reflects back to the transducer (echo)
- Some energy continues to penetrate deeper tissues (through transmission)
- Echo signals processed & combined
- Generates an image of the scanned slice
3
Q
What are the different transducer types
A
- Abdominal (Convex or Curved Array) Probes
- Cardiac (Sector Array) Probes
- Linear (Linear Array) Probes
4
Q
Describe an abdominal probe
A
- Frequency: 2-5 MHz
- Used for general abdominal imaging, trans abdominal pelvic imaging, obstetrical imaging, & some musculoskeletal imaging
- Allows imaging up to depths of 20 cm
- Wide angle field of view for large deeper structures
5
Q
Describe a cardiac probe
A
- Frequency: 1.5-4.5 MHz
- Produce a triangular sector image
- Suited for imaging large, non-superficial structures through narrow sonographic windows
- Not ideal for imaging superficial structures
6
Q
Describe a linear probe
A
- Frequency: 8-15 MHz
- Offer the best image detail but limited depth penetration (5-6 cm max from skin surface)
- Used foe musculoskeletal, peripheral nerves, thyroid gland, breast, & superficial vascular imaging
- Produce rectangular shaped imaging with constant width from probe face to deepest part
7
Q
Describe how to control and manipulating the probe
A
- “Drop an anchor”
- Manipulate pressure, stabilization, adjust angle, rotation, tilt (think of the US beam as a flashlight
- All probes have an orientation marker that corresponds to the display: scans along longitudinal axis the marker is oriented cranially; scans along the transverse axis the marker is oriented to the patients right; & structures near the top of the image are superficial
8
Q
Define echogenicity
A
- Reflectivity of tissue in relation to surroundings
- Visible contrast in brightness at tissue interfaces
9
Q
Describe the appearance of tissues on US image
A
- Hyperechoic (White): high reflectivity (ex. bone)
- Hypoechoic (Gray): moderate reflectivity (ex. muscle)
- Anechoic (Black): little to non reflectivity (ex. fat)
10
Q
What do nerves look like on ultrasound
A
- Transverse view: hyperechoic surface with hypoechoic nerve fascicles (honeycomb appearance)
- Longitudinal view: hypoechoic stripes parallel to eve’s long axis (bundle of straws appearance)
11
Q
What do blood vessels look like on ultrasound
A
- Blood is anechoic, vessel walls are hyperechoic
- Arteries have circular profile in transverse view, thicker walls than veins
- Veins are readily compressible, arteries require substantial pressure
12
Q
What does skin look like on ultrasound
A
- smooth & bright (hyperechoic)
- epidermis & dermis differentiation requires specialized high-resolution ultrasound
- subcutaneous layer appears generally hypo echoic with fat & connective tissue septae
13
Q
What does skeletal muscle look like on ultrasound
A
- Transverse view: anechoic/hypoechoic with hyperechoic lines (starry sky appearance)
- Longitudinal view: anechoic/hypoechoic with elongated hyperechoic lines revealing fascicular architecture
14
Q
What do tendons look like on ultrasound
A
- Longitudinal view: fibrillar appearance with hyperechoic border
- Transverse view: Bristle-brush appearance with distinct hyperechoic surface
15
Q
What does bone look like on ultrasound
A
- hyperechoic surfaces with acoustic shadowing deep to the bone surface
