L10.2 Introduction to sonography Flashcards
1
Q
Feaatures of ultrasound
A
- Requires a medium for transmission
- Air/bone does not transmit US well
- >20,000Hz
- Speed of sound I biological tissues = 1540m/s (slight variability)
- Attenuated signals coming back to the transducer
2
Q
White/black colours on sonogram
A
- Strong reflection → white
- Bones don’t reflect → black
3
Q
3 different views/techniques for US
A
- Parasternal long axis view (diameter ish)
- Parasternal short axis view (rotated 90o)
- Apical 4 chamber view
4
Q
What is spontaneous contrast
A
- Spontaneous contrast (blood shown in different colour on sonogram) → only apparent in low flow states
5
Q
How is pericardial effusion shown on sonograms
A
- Pericardial effusion → black region and strands going outside of heart seen → may compress heart