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17 Cards in this Set
- Front
- Back
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Artifacts
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- not real
- not seen on image -incorrect shape or size, position, and/or brightness |
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Causes of Artifacts
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- violation of assumptions
- equipment malfunction or poor design - the physics of ultrasound -operator error |
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Hyperechoic
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Portions of an image that are brighter than surrounding tissues
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Hypoechoic
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Portions of an image that are not as bright as the surrounding tissue
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Anechoic
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An extreme form of hypoechoic, echo free, fluid filled structure
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Isoechoic
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Structures with equal echo brightness
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Homogeneous
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A portion of tissue or an image that has similar characteristics throughout
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Heterogenous
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A portion of tissue or an image that has differing echo characteristics throughout
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Six Assumptions of Imaging Systems
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Reverberation
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-locational artifact
- located parallel to sound beams main axis, at ever increasing depths -resemble venetian blinds |
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Comet tail
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-Locational artifact
- appears as a single long hyperechoic echo - located parallel to the sound beams main axis - appears mostly due to metallic objects or calcifications |
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Ring down artifact
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-Locational artifact
- appears as a single long hyperechoic echo - located parallel to the sound beams main axis -appears due to gas bubbles |
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Shadowing
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-appears as hypoechoic or anechoic region extending downward
- result of too much attenuation -shadows may provide valuable diagnostic info that helps characterize the tissue |
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Edge shadow
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- hypoechoic or anechoic
- results when beam spreads after striking a curved reflector -extends downward from curved reflector edge - prevents visualization of true anatomy on the scan |
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Enhancement
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- occurs when the sound beam travels through a region of lower attenuation than surrounding tissue
- is the opposite of shadowing - clinically useful in diagnosing - Hyperechoic |
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Focal enhancement
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- Hyperechoic side to side region (appears the same as the foreground color)
- results from an increased intensity at the focus |
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Mirror image
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-second copy of a true reflector
- artifact appears deeper than true reflector - the mirror lies on a straight line between the artifact and the transducer - true reflector and artifact are equal distances from the mirror |
