What causes an axial artifact and how to fix it?
poor axial resolution, and increase frequency
what does axial artifact show?
the inability to distinguish two small or closely positioned structures
what causes lateral resolution artifact and how do you fix it?
poor lateral resolution and adjust focal zones, use multiple focuses, increase frequency, or utilize dynamic receive focusing
what is lateral resolution artifact showing?
aberrant signals from adjacent structures, possible lateral blurring of larger structures
what is elevational resolution artifact and how do you fix it?
poor elevational resolution and you fix it by adjusting focal zones, utilizing multiple focal zones, and use a 2-D array
what does elevational artifact show?
possible echoes with a hypo-echoic or anechoic structure
what is off axis side lobes/grating lobes artifact? and how do you fix it?
signals from outside the primary beam are reflected and displayed and use of harmonic imaging, adjust gain, alter acoustic window, and/or angle of insonation
what does off axis artifact show?
echoes in hypo-echoic or anechoic structures
what is a reverberation artifact and how do you fix it?
reflections between 2 highly reflective parallel interfaces and you fix it by use of harmonic imaging, adjust gain, change acoustic window or change angle of insonation
what is ring down artifact and how do you fix it?
resonant vibrations within gas bubbles and use of spatial compounding
what is comet tail artifact and how do fix it?
reverberations between 2 strong closely spaced reflectors and use spatial compounding
what is mirror image artifact and how do you fix it?
reflections from a strong reflecting interface and you fix it by adjusting your gain, change your acoustic window or adjust angle of insonation
what is multi-path artifact and how do you fix it?
low amplitude of off-axis signal form either transmission or reflection, change acoustic window or angle of insonation
what is refraction artifact and how do you fix it?
refraction of the energy at oblique angles of incidence, change acoustic window or angle of insonation
what is considered an refraction artifact?
mis-registration, ghosting, edge shadowing
what is speed error artifact and how do you fix it?
variability in the propagation speed from the assumed 1540m/s, some modern transducers allow for manual correction in sound speed
what is range ambiguity artifact and how do we fix it?
signals deeper than the depth of field are depicted within the next pulse, minimize by reducing PRF, reducing the # of focal zones, or increasing imaging depth
what are considered attenuation artifacts?
enhancement/increased through transmission, and acoustic shadowing
what is enhancement/increased through transmission artifact and how do you fix it?
increased amplitudes (intensity) of signals below a low attenuating structure, use of harmonic imaging or spatial compounding
what is acoustic shadowing artifact and how to fix it?
reduced or (no) amplitude (intensity) below a highly attenuating structure, decrease frequency, adjustment of focal zone, change acoustic window or angle of insonation
how do you fix cross talk artifact?
decrease gain
change angle from 90 degrees
what does focal banding look like and how do you fix it?
a horizontal beam
adjust TGC’s, move focus, decrease foci
how do you improve twinkle artifact
decrease PRF, decrease color write, move focus, increase 2D gray scale
How do you fix flash artifact?
Decrease your gain, increase your scale (PRF)
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Doppler44
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Optimizing doppler images22
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Imaging processing & display53
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Doppler shift*15
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Inspiration vs Expiration venous blood flow6
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Apply doppler48
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Lateral resolution*11
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Coded excitation*5
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Wall filter8
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Ergonomics6
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Dynamic range8
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Temporal resolution*16
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Artifacts25
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Mock 466
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Mock 363
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Mock 236
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Pulse repetition frequency*15
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Duty factor *7
