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PHYS3 Artifacts Hangman

 
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Artifact: Group(s) Correct by:
Axial resolution  Propagation  ↑ frequency  
Lateral resolution  Propagation  ↑ frequency  
Section thickness  Propagation  ↓ gain and/or TGC OR ↑ z axis (3rd dimension) focus  
Acoustic Speckle  Propagation  ↓ gain or ↓ frequency  
Reverberation  Propagation  multiple matching layers  
Refraction  Propagation  change angulation of transducer  
Multipath  Propagation  change angulation of transducer  
Mirror image  Propagation / Doppler  change angulation of transducer  
Side lobe  Propagation  inherent within the transducer ↓ gain  
Grating lobe  Propagation  inherent within the transducer ↓ gain  
Comet tail  Propagation  inherent within the tissue  
Ring-down  Propagation  inherent within the tissue  
Speed error  Propagation  inherent within the tissue  
Range ambiguity  Propagation / Doppler  PROPAGATION: ↓ PRF (↑PRP) by ↑ imaging depth DOPPLER: Need to ↑ PRF to decrease aliasing, but this can cause range ambiguity artifact  
Main bang  Propagation  • Multiple matching layers • Electronic focusing • ↑ Frequency • ↓ Near gain • Stand-off pad  
Shadowing  Attenuation / Doppler  inherent within the tissue  
Enhancement  Attenuation  inherent within the tissue  
Refraction (edge) shadowing  Attenuation  inherent within the tissue • Change angulation of transducer so it is perpendicular to anatomy  
Focal enhancement  Attenuation  inherent within the transducer • ↓ gain in mid field (or wherever the focal zone is – use TGC to adjust)  
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  
Speckle (noise)  Doppler  ↓ gain  
Doppler angle effects  Doppler  use “angle correct” control or change Doppler angle  
Clutter  Doppler  ↑ wall filter