Infographics / Ultrasound Physics

B-mode imaging artefacts

Five schematic panels of ultrasound artefacts named in the questions. Slice-thickness (partial volume): a finite-width beam averages adjacent tissue into a small cyst, adding spurious low-level echoes. Reverberation: comet-tail shows discrete equally spaced bands between two close reflectors while ring-down shows a continuous streak from trapped-gas resonance. Acoustic shadowing: a strongly reflecting calculus leaves a clean anechoic shadow deep to it. Mirror-image: specular reflection at the diaphragm duplicates the liver deep to the reflector. Clutter: off-axis side or grating lobes place spurious echoes along the main beam, filling fluid.

Ultrasound imaging artefacts and their causes Five schematic panels of ultrasound artefacts named in the questions. Slice-thickness (partial volume): a finite-width beam averages adjacent tissue into a small cyst, adding spurious low-level echoes. Reverberation: comet-tail shows discrete equally spaced bands between two close reflectors while ring-down shows a continuous streak from trapped-gas resonance. Acoustic shadowing: a strongly reflecting calculus leaves a clean anechoic shadow deep to it. Mirror-image: specular reflection at the diaphragm duplicates the liver deep to the reflector. Clutter: off-axis side or grating lobes place spurious echoes along the main beam, filling fluid. Ultrasound imaging artefacts and their cause Slice-thickness (partial volume) elevational slice thickness false echoes A finite beam samples a volume, averaging adjacent tissueinto a small cyst and adding spurious low-level echoes. Reverberation: comet-tail vs ring-down comet-tail ring-down Both are reverberation. Comet-tail: discrete equally spacedbands (spacing d = c t / 2). Ring-down: continuous streakfrom trapped-gas resonance. Acoustic shadowing (calculus) acoustic shadow A strong reflector transmits little sound, leaving aclean anechoic shadow deep to the stone. Mirror-image artefact true liver diaphragm mirror liver Specular reflection at the diaphragm duplicates the liverdeep to it; the scanner assumes a straight-line path. Clutter from side / grating lobes main beam side lobes off-axis gas fluid (anechoic) Off-axis lobe echoes are displayed along the main beam,filling fluid with low-level clutter (a near-field effect).
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