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1. Ultrasound waves are generated by send current through what crystals
1. piezoelectric crystals
1. Anechoic (no-echo) appear?
2. Hyperechoic waves appear?
1. What is the spacial pulse length?
1. number of cycles (1-2) x wavelength
How does sound travel through bone, liquids, air?
- 4080 m/s
- liquids/fat/muscle 1540m/s
- Air 330m/s
What is Attenuation?
- - the loss of US power through
- 1 Reflection
- 2 Scatter
- 3 Refraction
- 4 Absorption
1. What frequency is used for deep tissue visualization?
2. What frequency is used to visualize shallow?
- higher frequency gives a better or worse pic?
1. Less echogenic = hypoechoic and more echogenic = hyperechoic?
what is Isoechoic?
Same echogenicity as surrounding tissue.
- How do nerves appear?
- How do peripheral nerves appear?
- 1. Both Hypoechoic center and surrounded by Hyperechoic perimeter
- 2. honeycomb
- 3. not compressable
- how do muscles appear?
1. short axis view is what plane?
1. transverse plane - ex. arteries are round
Longitudinal plane appears?
- anechoic and tubular
- Round, regular, and pulsatile
- Oval, irregular, compressible, ^with valsalva, and expand with trendelenburg
How does Fat appear?
- dark - unless there is a tumor
- highly reflective
1. Artifact will always come back from bone and air. Why?
1. bc machine is calibrated for speed of 1540 m/s and bone is much faster... Gas much slower.
Artifacts can help confirm structures
- Dirty shadow
High attenuating tissues diminish posterior shadow while low attenuating tissue enhance echos posteriorly
What is Anisotropy
the change from hypo to hyperachoic based on transducer angle
What is Ultrasound?
- Ultrasound beam is the result of creating an
- electrical field across piezoelectric crystals
- on the transducers surface
- • Piezoelectricity - the ability of a material to
- generate an electrical potential following
- the application of mechanical stress
linear array attributes?
- 1:1 between contact surface area and image
- 1mm - credit card thin 2D
1. Blue and red denote what direction of flow?
2. Color doppler can be seen when placing the probe perpendicularly to the body?
- Red = towards transducer
- Blue = Away from transducer
What are the planes of needle introduction?
- 1. In plane = short axis
- 2. out of plane = long axis
What is the sliding technique?
Start transducer as close to needle as possible. slide transducer forward as you advance needle.
T/F short axis or transverse axis is used for needle insertion while longitudinal view to confirm catheter is inside the vessel?
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