Artifacts in Echocardiography

1. Artifacts in Echo
Dr Dilzith

2. Contents
• Artifacts
• In 2D Echo
• In Doppler
• In Colour flow
• In TEE

4. Artifacts
1. Extraneous US signal that results in appearance of structures that
are not actually present
2. Failure to visualize structures that are present
3. An image of a structure that differs in size or shape or both from its
actual appearance

5. 2-D Echo

7. Suboptimal Imaging
• Cause is poor ultrasound tissue penetration
• Body habitus with interposition of high attenuation tissue. (Lung,
Bone)
• Increased distance ( Adipose tissue)
• THI can improve the image quality
• TEE may be required

9. Acoustic Shadowing
• Reflection of entire US signal by a
strong specular reflector
• Ex:
• prosthetic valves.
• Heavily calcified Native structures
• Contrast containing blood also
produces shadowing.
• Try alternate acoustic window or
different transthoracic view
• TEE may be required

10. Reverberations
• Multiple linear high amplitude
echo signals originating from two
strong specular reflectors
• Results in back and forth reflection
• Typically, a reverberation artifact
that originates from a fixed
reflector will not move with the
motion of the heart.

11. Beam Width
• Superimposition of structures within the beam profile (Including side
lobes) into a single tomographic image
• Can be due to strong reflectors at the edge of a larger beam will be
superimposed on structures in central zone.
• Can be due to consequences of varying lateral resolution

12. Range Ambiguity
• Echo from previous pulse reaches transducer on next cycle.
• Results in appearance of deep structures closer to the transducer than their actual
location
• Second type of range ambiguity is a double image on the vertical axis
• Echoes being re-reflected by a structure close to the transducer (ex. Rib)
• Results in signal received twice normal and can form double image.
• Range ambiguity can be eliminated by decreasing depth or adjusting the transducer
position

13. Refraction
• Deviation of US signal from a
straight path along the scan line.
• Appearance of side-by-side
double image
• Commonly seen in parasternal
short axis view

14. Near Field clutter
• Also called as “Ringdown artefact”
• Arises from high amplitude oscillations
of the piezoelectric elements.
• The artifact is troublesome when trying
to identify structures that are
particularly close to the transducer
• Greatly reduced in modern day systems

15. Doppler Artifacts

17. Velocity Underestimation
• Due to non-parallel intercept angle between the US beam and
direction of blood flow

18. Signal Aliasing
• Inability to measure maximum
velocity
• Can be due to non-laminar
disturbed flow and high velocity
laminar flow
• Can be controlled by using low-
frequency, change Nyquist limit
and use of CW doppler

19. Beam width
• Superimposition of Doppler signals from adjacent
flows
• Beam width artifacts in Doppler imaging can be
clinically useful.
• beam width artifact often has less desirable effects.
Ex: a large sample volume may hinder
one's ability to distinguish aortic stenosis from mitral
regurgitation.

20. Range ambiguity
• It’s a speed of sound artefact
• Doppler signals from more than one depth along the US
beam are recorded.
1.misregistration of targets
2.distortion of interfaces
3.errors in size and
4.defocusing of the ultrasound beam.
• It can be reduced by decreasing the depth or width to the
minimum required

21. Mirror Imaging
• Also called as “Cross Talk”
• Such mirror images are usually less
intense but similar in most other
features to the actual signal.
• can be reduced by decreasing the
power output or gain and optimizing
the alignment of the Doppler beam
with the flow direction.

22. Transit Time Effect
• Change in the velocity of the US wave as it passes through a moving
medium results in overestimation of Doppler shifts
• Results in broadening of the velocity range at a given time point.
(Blurring on the vertical axis)

23. Colour Doppler

25. Shadowing and Ghosting
Shadowing:-
• may occur, masking color flow information beyond strong reflectors.
Ghosting:-
• is a phenomenon in which brief patterns of color are painted over
large regions of the image.
• Ghosts are usually a solid color (either red or blue) and bleed into the
tissue area of the image.
• These are produced by the motion of strong reflectors such as
prosthetic valves.

26. Background Noise
• Also called as Gain setting artifacts
• Too much gain can create a mosaic distribution of color signals
throughout the image.
• Too little gain eliminates all but the strongest Doppler signals and
may lead to significant underestimation.
• Gain level just below the random background noise can optimize the
flow signal

27. Other artifacts..
• Intercept angle: Change in
colour (or absence at 90
degrees) due to angle between
flowstream and US beam
• Aliasing: On colour flow results
in “wraparound” of the velocity
signal.
• Electronic interference:
Instrument dependent

28. In TEE

30. Multiple reflections

31. Misplaced reflections

32. Thank You!!