week 1- textbook notes Flashcards
Interfaces between tissue where large difference in impedance occurs, ___ results
bright echoes (specular reflectors)
An area on the image that has no echo is termed
anechoic
An aread with weak or low echo is termed
hypoehoic
A structure is of equal echogenicity to adjacent soft tissue it is described as
isoechoic
Normal tendons appear as
hyperechoic with fiber or fibrillar echotexture
Best axis to image continuous tendon fibers
long axis (sagittal)
proximal is seen on the __ side of the image
left
distal is seen on the ___ side of the image
right
Normal muscle tissue appears as ___
hypoechoic
muscle tissue is separated by hyperechoic _____ which surrounds the hypoechoic muscle bundles
perimysium / fibroadipose septa
Surface of bone or calcification is typically very ____ with posterior ___
hyperechoic
acoustic shadow
what may appear if the bone is smooth and flat
posterior reverberation
Hyaline cartilage covering the articular surface or bone is ___ and uniform, whereas fibrocartilage is ____
- hypoechoic
- hyperechoic
Ligament appearance
hyperechoic, striated
ligaments are ___ (more/ less) compact than tendons
more
Ligaments connect two ___ structures
osseous (bones)
identifying feature of peripheral nerves in short axis
honeycomb
why do peripheral nerves appear both hyper and hypoechoic?
depends on their surrounding tissue
Individual nerve fascicles are ___ (hyper/ hypoechoic) and surrounded by ____ connetive tissue epineurium
HYPOechoic
HYPERechoic
epidermis and dermic appear
hyperechoic
Tendons become more ____(hyper/hypoechoic) with an increased insonation angle
hypoechoic
tissue is anisotropic if ____
properties change when measured from different directions.
Because abnormal tendons and ligaments may also appear hypoechoic, it is important to focus on that segment of tendon or ligament that is____ to the ultrasound beam
perpendicular
how to fix anisotrophy
angle along the long axis of the tendon/ ligament
t/f: Anisotrophy is always a bad thing
FALSE
-can help distinguish the tendon/ ligament from hyperechoic fat
what type of shadow is seen from objects with a small radius and rough surface
clean shadow
what type of shadow is seen from objects with a large radius and smooth surface
dirty shadow
what shadow may occur at the edge of a structure such as a torn achilles or patellar tendon
refractile
when does posterior acoustic enhancement/ increased through transmission occur
when imaging fluid
what artifact occurs when the surface is smooth and flat such as a metal object or surface of bone
posterior reverberation
how can beam width artifact be reduced
adjusting focal zone to be at levelof object of interest
what two artifacts are a form of posterior reverb
- comet tail
- ring down
what US technique is helpful in imaging an entire muscle from origin to insertion (measuring large abnormalities)
extended field of view
alternative technique to extended field of view
split screen
-joins two images on the display & double field of view
refractile shadowing common with ___ surfaces
curved
what artifact is caused by returning sound waves that are passed between 2 tissues with remarkably different speeds
time of flight artifact
if the speed of sound is less than the average in the tissue, the artifact will appear ___ the transducer
farther away from
if speed of sound is more than the average in tissue, the artifact will appear ____ the transducer
closer to
time of flight artifact occurs most often when imaging what type of pt and why
obese
-more fat-muscle interfaces
small calcifications are common with ___ type of artifact
beam width
heel-toe rocking of transducer fixes ___ artifact
anisotropy
stand off pad or changing the angle of incidence fixes ___ artifact
reverberation
compound imaging or use of harmonics helps to reduce or eliminate ___ artifact
refractile
changing the angle of incidence helps to fix ___ artifact
time of flight
beams produced at several angles and combined together forming one image
spatial compounding
advantage of spatial compounding
improves tissue plane definition
disadvantage of harmonics
- depth of penetration suffers
- lose grey matter (looks black & white)
t/f: harmonic signals are present during the transmission
FALSE`
harmonic signals are formed ___ tissue
within
harmonic signals ___(are/are not) linear sound propagations
not
harmonics improve what resolution
axial and lateral
hyperemic means
increased vascularity
significant advantage of US over other imaging methods
dynamic capabilities
