The presentation highlights the artefacts in USG. The principle behind the formation of artefacts and ways to mitigate them.

1. Artifacts in USG
Dr Wangju Sumnyan MD
Professor & HOD, Department of Radiology & Imaging
TRIHMS

2. Objectives
• To define and identify artefacts in routine USG
• Techniques to reduce or minimize artefacts
• Exploit some artefacts for diagnostic utility

3. Artefacts in USG
• That does not correspond to or represent an actual anatomical or
pathological structure.
• an erroneous interpretation of a signal by the machine.

4. Artefacts
The ultrasound machine makes various assumptions in generating an
image. These include:
• The ultrasound beam only travels in a straight line in all body tissues
with a constant rate of attenuation.
with constant speed speed (1540m/s.)
as infinitely thin beam
with all echoes originating from its central axis.
• The depth of a reflector is accurately determined by the time
taken for sound to travel from the transducer to the reflector and
return.

5. Artefacts
1. Related to the instrument.
2. Technique related.
3. Artifacts due to sound reaction with various tissues.

6. Related to the instrument.
• Artifactual noise
• Main bang artefact
• Grating lobes
• Side lobes artifact
• Photographic artefact
• Motion artefact
• Calibration artefact

7. • Artifactual noise
Caused by electrical interference from nearby equipment /machine.

8. • Main bang artefact:
Disadvantages : The superficial lesions will be hidden.
Correction technique:
• Decrease the near gain
• Use a higher frequency transducer
• Use stand-off pads to evaluate superficial structures.

9. Grating lobes & Side lobes artifact
The ultrasound beam exits the transducer as a complex three-
dimensional bowtie shape with additional off-axis low-energy
beams.
These off axis beams also reflect corresponding to imaging
object and reach probe and so cause artefact.
Produce confusing echoes that arise from sound beams that lie
outside the main ultrasound beam.
Create impression of structures or debris in fluid filled
structures.
Eliminated by repositioning the transducer and proper
focusing.

10. Technique related.
• Noise
• TGC related artefacts
• Motion artefacts
• Operator scanning speed
• Operator pressure artifacts
• Contact artefact

11. TGC related artefacts

12. ARTIFACTS CAUSED BY MOVEMENT
• Breathing.
• Operator scanning speed.
• Operator pressure.

13. Artifacts due to sound interaction with
various tissues.
• Acoustic shadowing
• Acoustic enhancement
• Reverberation artefact
• Mirror image artefact
• Frezonal zone artefact
• Refraction / Split image artefact
• Slice thickness artefact
• Comet tail artefact
• Beam depth artefact
• Edge artefact

14. Reverbation artefact

17. Mirror image artefact

18. Mirror image artefact
Occurs when the US beam encounters a highly
reflective interface.
• Causes structures to be displayed twice
• One image is the mirror image of the other
• Commonly identified at the level of the
diaphragm
– liver parenchyma present in the expected location
of lung

19. Acoustic enhancement

20. SPLIT IMAGE/REFRACTION ARTIFACT
• Bending of the sound beam occurs so that target
not along the axis of transducer are insonated.
• There reflections are then detected and displayed
in the image.
• Structures that lie outside the volume appear in
the image.
• Example- vanishing twin phenomenon
• Correction is by Scanning from site other than
midline

21. Edge shadow artefact
US strikes circular objects and is scattered
and refracted
• Most marked at the edges
• Very little signal returns to the transducer
• Can lead to inaccuracy if measuring
structures in the transverse plane

22. Conclusion..
• Artifacts are common in USG.
• Artifacts are unavoidable and occur secondary to intrinsic physical
properties of the ultrasound beam.
• Recognition of these unavoidable artifacts is important because they
may be clues to tissue composition and aid in diagnosis.
• The ability to recognize and remedy potentially correctable artifacts is
important for image quality improvement.
• Exploit and use the artefacts to aid in diagnosis.

23. THANKS

24. Doppler related artefact
• Aliasing artefact
• Blooming artefact
• Twinkling artefact
• Spectral mirror image artefact

25. • noise