artifacts classified as Propagation, Attenuation, or and/or Doppler

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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