ECHO 2013 / Artifacts of Imaging and Doppler Know Your Physics
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Distinguishing Real from Artifact
Artifact
Color flow passes through true artifact
Clues: foreign materials
catheters, prosthetic valves, grafts (not always
in imaging plane)
Real Structure
Color flow respects structures and borders
Clues: associated findings
Intimal flaps associated with dilated aorta
Artifacts Classification: Physics of
Ultrasound
Resolution
Axial Resolution
Lateral Resolution
Elevational Resolution
Acoustic Speckle
Attenuation Artifacts
Shadowing
Enhancement
Focal enhancement
Refractory Shadowing
Propagation path
Reverberations
Ringdown
Multipath
Refraction
Mirror image
Side lobe and grating lobe
Miscellaneous
3D Artifacts
Comet-tail
Artifacts associated with electronic noise
Speed Error
Resolution Artifacts
Resolution
Axial: SPL/2, constant with depth
Lateral: far field beam widens,
Acoustic Speckle: occurs close to transducer and related to tissue scatter
Elevational: slice thickness/beam width artifact
Lateral Resolution Artifact: Beam
Width Varies with Depth
RV pacing wire from apical view
l D x f
θ1/D x f
Ultrasound property:
Lateral resolution varies directly with beam width
The greater the depth, the wider the beam
Artifact:
Displayed width of a point target varies with depth
Lateral Resolution Color Artifact
Ultrasound property:
Lateral resolution varies directly with beam width
The greater the depth, the wider the beam
Artifact:
May account for overestimation of mitral regurgitation severity
RV Foreign Object?
60 year old man, presents with palpitations and exertional chest pain
Ultrasound Property:
An ultrasound beam has measurable slice thickness
Beam Width Artifact
Strong reflecting anatomic structures (or side lobes) above and below the beam’s main axis may appear in the image
Slice Thickness
Artifact
Acoustic Speckle
Is the RV normal?
Speckle: unusual patterns of wave interference in the sound beam close to the surface of a tranducer which 
reduce image resolution.
Attenuation Artifacts
Attenuation occurs due to:
Absorption
Reflection
Scatter
Attenuation Artifacts
Shadowing
Enhancement
Attenuation Artifact: Acoustic Shadowing
Is there significant MR?
Ultrasound Property
Strong specular reflectors with marked impedance difference with reflect sound waves
Acoustic Shadowing
Absence of echoes beyond a strong reflecting surface
Correction
Change acoustic window
TEE