Ultrasounds Flashcards
importance of US
examine parenchymal and fluid filled organs
principles of US
sound waves with prequency too high for humans to hear
how are US images made
by sending a pulse of US into a tissue using a transducer/probe
what does the sound do
reflects ehcoes from the tissues and a part of them will be reflected to the probe.
what frequency is used
1-18megahertz
what is a sound wave produced by
piezoelectric transducer
fluid on US
no echoes will be reflected - black on screen
how is echo formed
sound wave encounters the border of 2 neighbouring materials with different densities and part of the wave is reflected back to the probe
acoustic impendance
density x acoustic velocity
what is the depth
the time taken for the echo to travel bacl to the probe
2 types of transducers
linear
sector
2 modes
M mode - 1D
doppler - 2D
red colour on doppler
flow is towards the probe
blue colour on doppler
blood flow is away from transducer
the more sound waves are reflected
the brighter the image
