A short presentation on 7 types of artifacts encountered in Ultrasonography

1. PRESENTED BY
Ms. DONISHA K JOHNSON
M.Sc. MEDICAL TECHNOLOGY
SEMESTER II
IMAGING SCIENES
IMAGING EQUIPMENT-
ULTRASONOGRAPHY
ULTRASOUND
ARTIFACTS

2. INTRODUCTION
•Artifacts in radiology refer to something
on an image that are not present in reality
appear due to a quirk of the modality itself.
•At times artifacts are welcome because
may be advantageous to the interpreter,
making anatomy/pathology easier to
appreciate
Ultrasound artifacts commonly encountered
are echoes that appear on the image but do
not have true correspondence to the
anatomical structure

3. TYPES OF ARTIFACTS
Beam width
artifact
Side lobe artifact
Speckle artifact
Inherent
Beam
characteristics
errors
Reverberation artifact
Comet tail artifact
Ring down artifact
Mirror image artifact
Multiple echo
errors
Acoustic
enhancement
Acoustic
shadowing
Attenuation
errors
Speed
displacement
artifact
Refraction artifact
Velocity
errors

4. BEAM WIDTH ARTIFACT
•OCCURRENCE :
•Distal beam may widen beyond the
actual width of the transducer this
results in poor lateral resolution
•REMEDIES:
•Adjusting the focal zone to the depth
level of interest
•By placing the transducer at the center
of the object being studied

5. • Appearance:
• there is lateral blurring of
the target anatomical
region along with
presence of echoes from
adjacent highly
echogenic object
• Clinical relevance:
• The reflections from
bowel generated by the
edge of the beam are
displayed inside the
sagittal view of the
urinary bladder where
the beam is centered

6. SIDE LOBE ARTIFACT
• OCCURRENCE:
•Echoes transmitted outside primary beam
are reflected back to transducer
•US assumes that all returning echoes arise
from the primary beam, the echoes are
falsely displayed within beam instead of at
their true location.
•REMEDIES: Can be reduced by
decreasing gain, using multiple windows,
advanced transducer design

7. A side lobe artifact (arrow) in the gallbladder lumen
causing a pseudosludge image , a finding that arises
from the adjacent echogenic wall.
•Appearance:
misplaces and
duplicates the
structures in an
anechoic or
hypoechoic
structures
•Clinical relevance:
mimicking debris in
anechoic structures
such as gall bladder
or urinary bladder

8. REVERBERATION ARTIFACT
• OCCURENCE
• The echo that returns to the transducer
after a single reflection will be displayed in
the proper location. The sequential echoes
will take longer to return to the transducer,
and the ultrasound processor will
erroneously place the delayed echoes at an
increased distance from the transducer.
• REMEDIES: Increase the amount of gel
used, decreasing gain, using multiple
windows

9. equally spaced echoes caused by the bouncing of the
sound wave between two strong reflectors (secular
reflectors) positioned parallel to the ultrasound beam.
•Appearance: Multiple
equidistantly spaced linear
reflections by production of
false echoes due to repeated
reflections between two
interfaces with a high
acoustic impedance
mismatch
•Clinical relevance: These
artifacts are often caused by
reflections between a
reflective interface and the
transducer or between
reflective interfaces, such as
metallic objects (e.g., bullet
fragments), calcified tissues,
or air pocket/partial liquid
areas of the anatomy.

10. COMET TAIL ARTIFACT
• OCCURRENCE
• Reverberations from closely spaced highly
reflective interfaces
• In this artifact, the two reflective interfaces and
thus sequential echoes are closely spaced.
• On the display, the sequential echoes may be
so close together that individual signals are not
perceivable
• REMEDIES:
• Decrease TGC near in the near gain
• Change beam angle / alternative window

11. Adenomyomatosis of the
gallbladder
•Appearance:
•Series of multiple, closely
spaced small bands of
echoes resembles a comet
tail, Comet tail artifact is a
form of reverberation.
•Clinical relevance:,
surgical clips, copper
intrauterine device,
ureteric calculi,
adenomyomatosis of the
gallbladder

12. REFRACTION ARTIFACT
• Occurrence: a change in velocity of
the ultrasound beam as it travels
through two adjacent tissues with
different density may produce a
refraction artifact.
•Remedies: varying AOI or imaging
window

13. Transverse US image of the liver
shows ghosting artifact of the aorta,
which appears in duplicate (arrows)
deep to the rectus abdominis
musculature
Appearance:
The ultrasound display
assumes that the beam
travels in a straight line and
thus misplaces the returning
echoes to the side of their
true location
Clinical relevance:
False position of lesions
during biopsy, can mimic
duplication of structures
(gestational sac, spinal cord,
aorta), cyst characterization
by using edge shadowing

14. ACOUSTIC ENHANCEMENT
• OCCURRENCE
• It is caused by the low level of
attenuation of the beam as it
passes through fluid.
• Increased intensity of echoes
distal to a low-attenuating
structure
•Remedies: May be increased
by using TH

15. • Appearance: This artifact
appears as a localized area of
increased echo amplitude
behind an area of low
attenuation.
• On a scan it will appears as an
area of increased brightness
• This artifact can often be an
useful diagnostic aid,
particularly when scanning a
soft-tissue mass or cyst
containing low level echoes.
• Clinical relevance:, and can
commonly be seen distal to fluid-
filled structures such as the urinary
bladder, GB or a cyst. Differentiation
of cystic from solid structures

16. ACOUSTIC SHADOWING
•OCCURRENCE:
•When the ultra- sound beam
encounters a strongly attenuating or
highly reflective structure, the
amplitude of the beam distal to this
structure is diminished
• Remedies: Increases with increased
frequency and THI; decreases with
inappropriate FZ placement,
excessive beam width

17. •Appearance:
Reduction in echo
strength distal to a
highly attenuating or
reflective object, it is
recognized as a dark or
hypoechoic band
known as a “shadow”
deep to a highly
attenuating structure
•Clinical relevance:
Detection of stones,
calcification, and air

18. THANK
YOU