artifacts classified as Propagation, Attenuation, or and/or Doppler
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
Help!
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| Axial resolution | Propagation | ↑ frequency
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| Lateral resolution | Propagation | ↑ frequency
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| Section thickness | Propagation | ↓ gain and/or TGC OR ↑ z axis (3rd dimension) focus
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| Acoustic Speckle | Propagation | ↓ gain or ↓ frequency
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| Reverberation | Propagation | multiple matching layers
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| Refraction | Propagation | change angulation of transducer
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| Multipath | Propagation | change angulation of transducer
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| Mirror image | Propagation / Doppler | change angulation of transducer
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| Side lobe | Propagation | inherent within the transducer ↓ gain
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| Grating lobe | Propagation | inherent within the transducer ↓ gain
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| Comet tail | Propagation | inherent within the tissue
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| Ring-down | Propagation | inherent within the tissue
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| Speed error | Propagation | inherent within the tissue
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| Range ambiguity | Propagation / Doppler | PROPAGATION: ↓ PRF (↑PRP) by ↑ imaging depth
DOPPLER: Need to ↑ PRF to decrease aliasing, but this can cause range ambiguity artifact
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| Main bang | Propagation | • Multiple matching layers
• Electronic focusing
• ↑ Frequency
• ↓ Near gain
• Stand-off pad
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| Shadowing | Attenuation / Doppler | inherent within the tissue
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| Enhancement | Attenuation | inherent within the tissue
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| Refraction (edge) shadowing | Attenuation | inherent within the tissue
• Change angulation of transducer so it is perpendicular to anatomy
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| Focal enhancement | Attenuation | inherent within the transducer
• ↓ gain in mid field (or wherever the focal zone is – use TGC to adjust)
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| Aliasing | Doppler | • Adjust baseline
• Adjust scale
• ↑ PRF
• ↑ Doppler angle (only if bad to begin with – must remain between 45° and 60°)
• ↓ transducer frequency
• ↓ sample volume depth
• Use CW Doppler
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| Speckle (noise) | Doppler | ↓ gain
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| Doppler angle effects | Doppler | use “angle correct” control or change Doppler angle
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| Clutter | Doppler | ↑ wall filter
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Created by:
lefut
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