| 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 |
or...
