MIDTERM Flashcards
A structure in an image which does not directly correlate with actual tissue being scanned
ULTRASOUND ARTIFACTS
any part of an image that does not accurately represent the anatomic structures present within the subject being evaluated
ULTRASOUND ARTIFACTS
other term for ULTRASOUND ARTIFACTS
pitfalls
This is the production of spurious (false) echoes due to repeated reflections between two interfaces with a high acoustic impedance mismatch.
reverberation
artifact that appear as a dense tapering V- shaped trail of echoes beyond strong reflectors
comet tail
short rapid reverberations
comet tail
similar to comet tail except that the bright artifact echoes are displayed in a much longer stream. The continuous echoes is seen deep to a strong reflector.
ring down
how to eliminate reverberation artifacts
- Increase the amount of gel used.
- Use a stand-off pad (such as commercially produced gel pad or bag of saline.
- Reduce gain
- Move the position of the transducer
This area appears as an area of low amplitude echoes (hypoechoic or anechoic) behind an area of strongly attenuating tissue
acoustic shadowing
shown best in calcifications
acoustic shadowing
This appears as a localized area of increased echo amplitude behind an area of low attenuation.
ACOUSTIC ENHANCEMENT
will appear as an area of increased brightness, and can commonly seen distal to the fluid filled structures such as the urinary bladder, the gallbladder or cyst.
ACOUSTIC ENHANCEMENT
A combination of refraction and reflection occurring at the edges of rounded structures and when the speed of sound is different from that surrounding tissue, it will result in an edge shadowing artifact
edge shadowing
. When an echo from such side lobe beam becomes strong enough and returns to the receiver, it is ‘assigned’ to the main beam and displayed at a false location
side lobes artifacts
these artifacts are usually seen in hypoechoic or echo-free structures and appear as bright and rounded line.
side lobes artifacts
They arise due to specular reflection of the beam at a large smooth interface.
mirror image artifact
Areas on the image showing no internal echoes
ANECHOIC OR SONOLUCENT
black or dark on the image.
ANECHOIC OR SONOLUCENT
Areas on the image with more reflected echoes
ECHOGENIC OR HYPERECHOIC
brighter than surrounding tissue.
ECHOGENIC OR HYPERECHOIC
Areas on the image with fewer reflected echoes
HYPOECHOIC
darker than the surrounding tissue.
HYPOECHOIC
Area on the image showing a level of reflected echoes similar to that of surrounding tissue
ISOECHOIC
For Two adjacent organs
ISOECHOIC
The arrangement of reflected echoes as “dots” on the image is referred to as
textures
B-mode scanning, the amplitudes of the returning signals are displayed on a gray scale from white (strong echo) to black (no echo perceived) and in between shades of gray
ultrasound textures
Organ parenchyma is UNIFORM in echogenicity
HOMOGENOUS
Organ parenchyma is NOT uniform in echogenicity
INHOMOGENOUS or
HETEROGENOUS
