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Basics of Ultrasound (2), AMIRUL HAKIMI BIN JAMIL A17SC0284 - Coggle…
Basics of Ultrasound (2)
Attenuation
deeper wave travels in the body, weaker it becomes
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absorption
longer it travels, more less its resolution
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attenuation coeffecient
gas/fluid: low coefficient (allow wave to pass), bones: high coefficient (blocks the wave).
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acoustic impedance
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when u/s beam encounters at 2 region at diff a.imp, beam is reflected/absorbed. (cannot totally penetrate; soft tissue & bone interface)
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types of resolution
axial
specifies how close of 2 together can be along axis of beam, yet still detected as 2 separate objects. (frequency affects the resolution)
lateral
ability to resolve 2 adjacent object that perpendicular to beam axis as separate objects. (beamwidth)
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temporal
ability to accurately locate position of moving structures at particular instants in time (frame rate), important in cardiology
image on monitor
amplitude: dot, dot position: depth echo received, dot brightness: strength of returning echoes
reflected echoes
strong: white dot (pericardium,diaphragm), weaker: grey (liver, myocardium), zero: black (gall bladder, intra cardiac cavities
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