lesson 9 Flashcards
(18 cards)
- the ability to reflect or transmit US waves in the context of surrounding tissues.
- is the ability to bounce an echo
ECHOGENICITY
- Echogenicity is higher when the surface bounces the sound echo reflecs
increased sound waves. - White on screen/ the structure appears brighter (more echogenic)
Hyperechoic
- Tissues with lower echogenicity.
- Gray on screen
Hypoechoic
- Echo-free, structure appears black,
- No internal echoes are produced (bounced) from the structure
Anechoic
- Same echogenicity in surrounding structures.
- structure exhibits the same brightness as its
surround structure
ISOECHOIC
Characterized by the apparent lack of signal
deep to an imaged tissue interface, due to all
(or nearly all) of the transmitted sound wave
being being reflected back to the transducer or
absorbed by the tissue.
ACOUSTIC SHADOWING
Refers to the increased echoes deep within structures that transmit sound exceptionally well.
- This is characteristic of fluid-filled structures such as cysts, the urinary bladder and the gallbladder.
ACOUSTIC ENHANCEMENT
- Occurs when an ultrasound beam encounters two strong parallel reflectors.
- When the ultrasound beam reflects back and forth between the reflectors
REVERBERATION ARTIFACT
- Abrupt mis-mapping of an object along the direction of the beam axis
- Cause: Variations of the speed of sound between beam projections.
SPEED
- A second inverted object appears beyond a highly reflective surface (eg, Diaphragm)
- Cause: Multiple beam reflections between the
object and the highly reflective surface
MIRROR ARTIFACT
- In color Doppler imaging mode, a region appears as a rapidly changing mix of colors.
- Cause: The presence of small, strongly reflective objects within the Doppler study
TWINKLING ARTIFACT
Phenomenon inherent to Doppler modalities, which utilize intermittent sampling in which an insufficient sampling rate results in an inability to record direction and velocity accurately
ALIASING
Type of artifact encountered in ultrasound-guided needle techniques, which results in the
apparent bending of the needle as it passes
into or adjacent to tissue with a different sound
transmission speeds
BAYONET ARTIFACT
occurs when the color signal indicating blood flow extends beyond its true boundaries, spreading into the adjacent regions with no actual flow
BLOOMING ARTIFACTS
or Color bleed artifact
Grey scale. Ultrasound findings are seen when small calcific/crystalline / highly reflective objects are interrogated, and are believed to be a special form of reverberation artifact
COMET TAIL ARTIFACTS
- Seen with color flow Doppler ultrasound.
- It occurs as a focus of alternating colors on Doppler signal behind a reflective object (such
as a calculus or air), which gives the appearance of turbulent blood flow
TWINKLING ARTIFACT
Artifacts in ultrasound imaging may result from
faults in the transducer itself or the transducer cable
TRANSDUCER-RELATED ARTIFACT
WHAT ARE THE PITFALLS OF ULTRASOUND
- Sound waves don’t travel through air or bone, so ultrasound isn’t effective at imaging body parts that have gas or are hidden by bone, such as the lungs or head.
- Ultrasound is unable to see objects that are located deep in the human body.
